Medical terminology and abbreviations

12-leadTWELV-leed

The standard diagnostic ECG recording twelve simultaneous leads, used to localize myocardial infarction and conduction abnormalities.

Plain: An ECG that watches the heart from twelve angles at once, which helps find exactly where a heart problem is.

The 12-lead is the standard diagnostic ECG. Because it looks at the heart from twelve angles, it can pinpoint which wall is starved of blood and confirm a STEMI.

15-leadfif-TEEN-leed

A 12-lead ECG with added right-sided and posterior leads (V4R, V8, V9) to detect right ventricular and posterior infarction the standard twelve can miss.

Plain: An ECG with three extra angles added so the team can also see the right side and back of the heart.

Adding right-sided and posterior leads to the usual twelve helps catch right ventricular and back-wall heart attacks that a plain 12-lead can hide.

Aberrancyuh-BAIR-un-see

Supraventricular conduction through a transiently refractory bundle branch, widening the QRS so it mimics a ventricular beat.

Plain: When a beat from the top of the heart travels down an odd path and looks wide, like a beat from the bottom.

Aberrant conduction happens when the electrical highways are briefly not ready, so a normal beat spreads slowly and looks wide. It can mimic ventricular tachycardia.

Accessory pathwayak-SESS-uh-ree PATH-way

An abnormal congenital conduction connection between atria and ventricles that bypasses the AV node, the substrate of WPW.

Plain: An extra electrical wire in the heart that lets the signal skip its normal checkpoint.

An accessory pathway is abnormal wiring that bypasses the AV node. It underlies WPW and can allow very fast, sometimes dangerous, rhythms to develop.

ACSay-see-ESS

Acute coronary syndrome: the spectrum of acute myocardial ischemia from unstable angina through NSTEMI to STEMI, caused by coronary plaque rupture and thrombosis.

Plain: A group name for sudden drops in blood flow to the heart, from warning chest pain up to a full heart attack.

Anginaan-JY-nuh

Chest pain from myocardial ischemia when oxygen demand outstrips supply; stable angina is exertional and eases with rest, unstable angina occurs at rest.

Plain: Chest pain or tightness that happens when the heart muscle is not getting enough blood, often during effort.

Angina is the warning symptom of a heart short on blood. Stable angina comes with effort and eases with rest; unstable angina appears at rest and signals a higher risk of heart attack.

Asystoleay-SISS-toh-lee

Absence of ventricular electrical activity, seen as a flat line; a non-shockable cardiac arrest rhythm confirmed in two leads.

Plain: The heart has no electrical activity at all and shows a flat line. A shock will not help this kind of cardiac arrest.

Asystole means the heart is electrically silent. It is confirmed in two leads, treated with CPR and epinephrine, and is not shockable. Fine VF must be ruled out first.

Atrial fibrillationAY-tree-ul fib-ril-AY-shun

A supraventricular arrhythmia with disorganized atrial activity, absent P waves, and an irregularly irregular ventricular response.

Plain: The top of the heart quivers instead of beating cleanly, giving a random, uneven pulse.

In atrial fibrillation there are no organized P waves, just a wavy baseline, and the beats come at random spacing. Blood can pool and clot, which raises the risk of stroke.

AV blockay-vee BLOK

Impaired conduction of the atrial impulse to the ventricles through the AV node or His-Purkinje system, graded first to third degree.

Plain: The electrical signal has trouble passing from the top of the heart to the bottom. It may be slowed or fully stopped.

AV block is graded by severity. First degree only slows the signal, second degree drops some beats, and third degree blocks all of them so the top and bottom beat independently.

AV nodeay-vee NOHD

The atrioventricular node, the normal conduction bridge from atria to ventricles, whose delay allows ventricular filling before contraction.

Plain: The electrical gate between the top and bottom of the heart. It briefly holds the signal before passing it down.

The atrioventricular node is the only normal electrical bridge from atria to ventricles. Its built-in delay lets the top chambers finish filling before the bottom ones squeeze.

Bradycardiabray-dee-KAR-dee-uh

A heart rate less than 60 beats per minute in an adult.

Plain: The heart is beating too slowly, under about 60 times a minute.

Bradycardia matters when the slow rate is too weak to supply the body, causing dizziness, low blood pressure, or a drop in alertness. Atropine and pacing are the usual first responses.

Bundle branch blockBUN-dul branch BLOK

A conduction delay or block in the right or left bundle branch, widening the QRS as one ventricle depolarizes late.

Plain: One of the two electrical wires to the bottom of the heart is blocked, which makes the ECG spike wider.

The signal normally splits down a right and a left branch. If one branch is blocked, that side depolarizes late through slower muscle, so the QRS becomes wide and altered.

Cardiac arrestKAR-dee-ak uh-REST

Sudden cessation of effective cardiac output, with no palpable pulse and absent or agonal breathing; the rhythm is VF, pulseless VT, asystole, or PEA.

Plain: The heart stops pumping blood, so the person has no pulse and stops breathing normally. It is an emergency.

Cardiac arrest can be caused by VF, VT, asystole, or PEA. Treatment is immediate high-quality CPR, and defibrillation if the rhythm is shockable.

Cardioembolic strokekar-dee-oh-em-BOL-ik STROHK

An ischemic stroke from a thrombus that forms in the heart (often in atrial fibrillation), embolizes, and occludes a cerebral artery.

Plain: A stroke caused by a clot that formed in the heart, broke loose, and traveled up to block an artery in the brain.

In atrial fibrillation blood can pool and clot in the heart. If a clot breaks free it can lodge in the brain, causing a cardioembolic stroke, which is why blood thinners are considered.

Delta waveDEL-tuh wayv

A slurred QRS upstroke from early ventricular activation over an accessory pathway, the hallmark of WPW pre-excitation.

Plain: A slurred, slanted start to the tall spike, caused by an extra electrical shortcut inside the heart.

A delta wave is the fingerprint of an accessory pathway. Because that extra route lets the signal reach the ventricles early, the upstroke of the QRS looks smeared instead of sharp.

Depolarizationdee-poh-lur-ih-ZAY-shun

The electrical discharge of cardiac cells that triggers contraction, inscribed as the P wave and QRS on the ECG.

Plain: The electrical firing that makes heart muscle squeeze. It shows up as the spikes on the ECG.

ECGee-see-JEE

A tracing of the heart's electrical activity, its depolarization and repolarization, displayed as a repeating waveform used to diagnose rhythms and ischemia.

Plain: A test that records the tiny electrical signals of your heartbeat as a wavy line, so the team can see how your heart is beating.

An ECG (also written EKG) picks up the small electrical signals that make the heart beat and traces them as a waveform. Reading the shape and timing of that wave is how rhythms and heart attacks are spotted.

EctopyEK-toh-pee

A beat arising from an ectopic focus outside the sinus node, firing off the expected sinus schedule.

Plain: An extra heartbeat that starts from an unusual spot instead of the heart's normal starting point.

Ectopic beats fire early from somewhere other than the sinus node. They are common and often harmless but can be a warning of an irritable heart.

Escape rhythmes-KAYP RITH-um

A subsidiary pacemaker (junctional or ventricular) that takes over when the sinus node fails or is blocked, sustaining a rhythm.

Plain: A backup heartbeat that kicks in when the heart's normal starter fails, keeping some beat going.

Fibrillationfib-ril-AY-shun

Rapid, disorganized, asynchronous contraction of cardiac muscle in place of a coordinated depolarization.

Plain: Heart muscle twitching in a fast, messy way instead of squeezing together as one.

Fibrillation describes muscle quivering out of sync. In the atria it is a common, survivable rhythm; in the ventricles it is a cardiac arrest that needs defibrillation.

First degree AV blockfurst-dih-GREE ay-vee BLOK

First degree AV block: prolonged AV conduction with a PR interval over 200 ms, but every atrial impulse still conducts to the ventricles.

Plain: The mildest kind of signal delay: every beat still gets through, it just takes a bit longer than normal.

Hyperacute T waveshy-per-uh-KEWT TEE

Tall, broad-based T waves that are the earliest ECG sign of an evolving STEMI, preceding ST elevation; mimicked by hyperkalemia.

Plain: Extra tall, wide T bumps that can be the very first ECG warning of a heart attack, even before other changes show up.

Hyperacute T waves are large and wide based. They are the earliest ECG sign of a developing STEMI, so catching them early can shorten the time to treatment. High potassium can mimic them.

Idioventricular rhythmid-ee-oh-ven-TRIK-yoo-lur

A ventricular escape rhythm (about 20 to 40 bpm) with wide QRS complexes, arising when higher pacemakers fail.

Plain: A slow backup heartbeat made by the bottom of the heart when the higher starters stop working.

An idioventricular rhythm is the last-resort pacemaker of the ventricles, usually 20 to 40 beats per minute with wide QRS complexes. It is slow and often unstable.

Infarctionin-FARK-shun

Necrosis of tissue caused by a sustained interruption of its blood supply; myocardial infarction is this process in heart muscle.

Plain: Tissue dies because its blood supply was cut off. A heart attack is this happening to heart muscle.

Infarction is the permanent damage that follows when ischemia is not relieved in time. A myocardial infarction, or heart attack, is death of heart muscle from a blocked coronary artery.

Ischemiaiss-KEE-mee-uh

Inadequate blood supply to tissue for its metabolic demand, causing hypoxia that is often reversible if perfusion is restored.

Plain: A body part is not getting enough blood and oxygen. It can often recover if blood flow comes back quickly.

Ischemia is starvation of oxygen from reduced blood flow. In the heart it causes chest pain and ECG changes; if it lasts too long, the tissue dies, which is infarction.

J wave (Osborn wave)JAY-wayv

A positive deflection at the QRS-ST junction (the J point), the Osborn wave characteristic of hypothermia, enlarging as the core cools.

Plain: A small hump on the ECG most often seen when a person is dangerously cold.

The J wave, also called the Osborn wave, sits at the junction between the QRS and the ST segment. It is a hallmark of hypothermia and grows larger as the body cools.

Junctional rhythmJUNK-shun-ul

A rhythm originating in the AV junction, often with an absent, inverted, or buried P wave and a rate near 40 to 60 bpm.

Plain: A backup heartbeat that starts near the middle of the heart when the normal starter fails or slows down.

A junctional rhythm arises from the AV junction. Because the signal starts lower than usual, the P wave may be missing, buried, or inverted, and the rate is often slow.

LBBBell-bee-bee-BEE

Left bundle branch block: delayed left ventricular conduction widening the QRS. A new LBBB with ischemic symptoms is a STEMI equivalent (Sgarbossa criteria).

Plain: A block in the left electrical wire of the heart. A brand new one with chest pain is treated like a heart attack.

Left bundle branch block widens the QRS and changes its shape. A brand new LBBB in a patient with chest pain is a STEMI equivalent, and the Sgarbossa criteria help judge it.

LeadLEED

One electrical view of the heart recorded between a defined set of electrodes; each lead records the myocardium from a different angle.

Plain: One camera angle on the heart's electrical signal. Each lead watches the heart from a different direction.

A lead is not just a wire. It is a specific viewpoint of the heart's electrical activity. Different leads face different walls of the heart, so comparing them shows where a problem sits.

MobitzMOH-bits

The two forms of second degree AV block (Mobitz I and II), in which some atrial impulses conduct to the ventricles and some are blocked.

Plain: A name for two kinds of partial signal block, where some beats reach the bottom of the heart and some get dropped.

Mobitz I and Mobitz II are the two forms of second degree AV block. Type I is usually harmless; type II is dangerous because beats drop without warning and it can worsen suddenly.

Mobitz IIMOH-bits TOO

Second degree AV block with constant PR intervals and intermittent non-conducted P waves; an infranodal block that may progress to complete block.

Plain: A partial block where beats are suddenly skipped with no warning. It can turn into a complete block.

In Mobitz II the conduction time stays constant and then a beat simply fails. Because the block is low in the system and unpredictable, it often needs a pacemaker.

Monomorphicmon-oh-MOR-fik

Describes QRS complexes of uniform morphology, as in classic monomorphic ventricular tachycardia.

Plain: When all the heartbeats look the same shape on the ECG.

Normal sinus rhythmSY-nus RITH-um

The normal rhythm originating in the sinoatrial node, regular at 60 to 100 bpm, with an upright P wave before every QRS.

Plain: The heart's normal, healthy beat: a steady 60 to 100 times a minute started by its own natural pacemaker.

Normal sinus rhythm is the baseline everything else is compared to. Each beat starts in the sinus node, so there is one upright P wave before every normal QRS.

NSTEMIen-STEM-ee

Non-ST-elevation myocardial infarction: subtotal coronary occlusion causing infarction without ST elevation, confirmed by a troponin rise.

Plain: A heart attack where the artery is only partly blocked. Blood tests confirm it because the ECG lift is not there.

In an NSTEMI the heart muscle is damaged but the ECG shows depression or T wave changes rather than clear elevation. Rising troponin blood levels confirm it.

P wavePEE-wayv

The ECG deflection produced by atrial depolarization; one upright P wave before each QRS indicates a sinus-origin beat.

Plain: A small bump on the ECG that happens when the top of the heart squeezes. Normally one shows up before each beat.

The P wave marks the electrical signal moving through the atria, the top chambers. A missing, extra, or oddly shaped P wave is a clue that the beat did not start in the usual place.

PACpee-ay-SEE

A premature atrial contraction: an early beat from an ectopic atrial focus, with an abnormal P wave and usually a narrow QRS.

Plain: An early, extra heartbeat that starts in the top of the heart.

PEApee-ee-AY

Pulseless electrical activity: an organized ECG rhythm without a palpable pulse or effective cardiac output; a non-shockable arrest.

Plain: The ECG shows a normal-looking beat, but the heart is not actually pumping any blood. It is a cardiac arrest.

In PEA the monitor looks like it should have a pulse, but there is none. It is a non-shockable arrest treated with CPR, epinephrine, and a hunt for the reversible cause.

Polymorphicpol-ee-MOR-fik

Describes QRS complexes of continuously varying morphology, as in torsades de pointes.

Plain: When the heartbeats keep changing shape on the ECG.

PR intervalpee-arr IN-ter-vul

The interval from atrial depolarization to the onset of ventricular depolarization (normally 120 to 200 ms), reflecting AV conduction time.

Plain: The short gap on the ECG between the top of the heart firing and the bottom firing. It shows how long the signal takes to travel down.

The PR interval measures how long the electrical signal takes to travel from the top chambers through the gatekeeper node to the bottom chambers. A long PR means slowed conduction.

Pre-excitationpree-ek-sy-TAY-shun

Early ventricular activation over an accessory pathway that bypasses the AV nodal delay, producing a short PR interval and a delta wave.

Plain: When part of the lower heart fires early because the signal took a shortcut instead of the normal path.

Pre-excitation is what the delta wave and short PR of WPW show: the ventricles are activated ahead of time through an accessory pathway, bypassing the AV node's built-in delay.

Precordial leadspree-KOR-dee-ul

The six chest electrodes V1 to V6 that record the heart in the horizontal plane, viewing the septal, anterior, and lateral walls.

Plain: The six ECG stickers placed across the front of the chest, right over the heart.

The precordial or chest leads sit directly over the heart and each one views a slightly different area, letting you follow how the electrical signal spreads across the front wall.

PVCpee-vee-SEE

A premature ventricular contraction: an early, wide-complex beat from an ectopic ventricular focus.

Plain: An early, extra heartbeat that starts in the bottom of the heart. Now and then these are common and usually harmless.

A premature ventricular contraction is an extra beat from the ventricles. Occasional PVCs are common and usually benign; frequent ones can signal an irritated heart.

QRS complexkew-arr-ESS

The ECG deflection of ventricular depolarization; a duration over 120 ms (wide) indicates abnormal conduction or a ventricular origin.

Plain: The tall spike on the ECG that happens when the main pumping part of the heart squeezes.

The QRS shows the ventricles firing. A narrow QRS (under 120 ms) means a normal fast path; a wide QRS means the signal spread slowly or started in the ventricles themselves.

QT intervalkew-tee IN-ter-vul

The interval spanning ventricular depolarization and repolarization; prolongation predisposes to torsades de pointes.

Plain: The time the heart's main chambers take to fire and then get ready again. If it lasts too long, a dangerous rhythm can start.

The QT interval covers depolarization and recovery of the ventricles. When it stretches too long, the heart can slip into torsades de pointes, so drugs and low electrolytes that prolong it matter.

R wave progressionarr-wayv proh-GRESH-un

The normal increase in R wave amplitude from V1 to V6; poor progression suggests anterior infarction or lead misplacement.

Plain: The way the tall ECG spike normally gets bigger across the chest leads. A poor pattern can hint at heart damage.

RBBBarr-bee-bee-BEE

Right bundle branch block: delayed right ventricular conduction widening the QRS, with an rSR' rabbit-ear pattern in V1.

Plain: A block in the right electrical wire of the heart. On its own it is often harmless.

Right bundle branch block is often harmless on its own. A brand new RBBB can point to a large clot in the lung, right heart strain, or a blockage high in the left coronary artery.

Reciprocal changesreh-SIP-ruh-kul CHAYN-jez

ST depression in leads opposite an infarcting wall, mirroring the ST elevation and raising confidence in a true STEMI.

Plain: Mirror-image ECG changes on the opposite side from a heart attack. They help prove the heart attack is real.

When one wall lifts its ST segment in a STEMI, leads looking at the opposite wall often show depression. These reciprocal changes strengthen the diagnosis.

Repolarizationree-poh-lur-ih-ZAY-shun

The electrical recovery of cardiac cells after depolarization, restoring readiness for the next beat, inscribed as the T wave.

Plain: The electrical reset of heart muscle after it fires, getting it ready for the next beat.

ROSCROSK

Return of spontaneous circulation: restoration of a palpable pulse and perfusion after cardiac arrest, often heralded by a rise in EtCO2.

Plain: The moment a person whose heart had stopped gets their own pulse back.

ROSC is the goal of resuscitation. A sudden jump in the exhaled CO2 reading during CPR is often the earliest sign it has happened, even before a pulse can be felt.

SA nodeess-ay NOHD

The sinoatrial node, the heart's dominant pacemaker in the right atrium, which initiates each normal sinus beat.

Plain: The heart's natural pacemaker, a small spot in the top of the heart that sets the beat.

The sinoatrial node fires the electrical signal that starts each normal beat. When it sets the pace, the rhythm is called sinus.

Sgarbossa criteriasgar-BOH-suh

ECG criteria for diagnosing acute myocardial infarction in the presence of a left bundle branch block or a ventricular paced rhythm.

Plain: A checklist that helps spot a heart attack on an ECG that already looks unusual from a left bundle block or pacemaker.

A left bundle branch block hides the usual heart attack signs. The Sgarbossa criteria give specific ST changes that still indicate a STEMI despite that baseline abnormality.

Sine wave patternSYNE-wayv

A broad, undulating waveform from loss of P waves and marked QRS widening, a pre-terminal sign of severe hyperkalemia.

Plain: A smooth, rolling ECG that has lost its normal spikes. It is a late, very dangerous sign of high potassium.

As potassium climbs to a life-threatening level, the P waves vanish and the QRS widens until the tracing looks like a rolling sine wave. It signals that cardiac arrest is close.

ST depressioness-tee dee-PRESH-un

Depression of the ST segment below baseline, indicating subendocardial ischemia or a reciprocal change opposite a STEMI.

Plain: When that flat part of the ECG dips lower than normal. It often means the heart is short of blood but not fully blocked.

ST depression points to the inner layer of heart muscle being starved of oxygen. It can also appear opposite a wall that is having a full heart attack, called a reciprocal change.

ST elevationess-tee el-uh-VAY-shun

Elevation of the ST segment above baseline, a marker of transmural myocardial injury from acute coronary occlusion (STEMI).

Plain: When that flat part of the ECG rides higher than normal. It warns that a heart artery may be fully blocked.

ST elevation in a group of leads that face the same wall usually means an artery is completely blocked and heart muscle is dying. It is the trigger for activating the cath lab.

ST segmentess-tee SEG-ment

The normally isoelectric segment between the QRS and T wave; deviation from baseline reflects myocardial injury or ischemia.

Plain: A flat part of the ECG just after the tall spike. Whether it sits level, high, or low tells the team about blood flow to the heart.

The ST segment normally sits on the baseline. Lifting it up or pushing it down is one of the most important signals of a heart attack or lack of blood flow to the muscle.

STEMISTEM-ee

ST-elevation myocardial infarction: complete coronary occlusion causing transmural infarction, with ST elevation in contiguous leads; a cath-lab emergency.

Plain: A major heart attack where a heart artery is fully blocked. The ECG shows a tell-tale lifted line.

A STEMI means a complete blockage of a heart artery is killing muscle. It is a time-critical emergency: the treatment is fast reopening of the artery in the cath lab, plus aspirin.

SVTess-vee-TEE

A regular narrow-complex tachycardia (commonly 150 to 250 bpm) arising above the ventricles, often from AV nodal re-entry.

Plain: A sudden very fast heartbeat that starts in the upper part of the heart, sometimes over 150 beats a minute.

Supraventricular tachycardia produces a fast, narrow, regular ECG. Vagal maneuvers and adenosine are tried first; if the patient is unstable, a timed electrical shock is used.

T waveTEE-wayv

The ECG deflection of ventricular repolarization; inversion, peaking, or hyperacute change flags ischemia and electrolyte disturbance.

Plain: A rounded bump after the tall spike, made as the heart's main chambers get ready for the next beat.

The T wave shows the ventricles resetting for the next beat. Inverted, peaked, or unusually tall T waves each point to different problems, from lack of blood flow to high potassium.

Tachycardiatak-ih-KAR-dee-uh

A heart rate greater than 100 beats per minute in an adult.

Plain: The heart is beating too fast, quicker than about 100 times a minute.

Tachycardia is a general term for a fast heart. Sinus tachycardia is usually the body responding to fever, pain, blood loss, or fear, while other fast rhythms come from electrical problems.

Third degree AV blockthurd-dih-GREE ay-vee BLOK

Third degree (complete) AV block: no atrial impulse conducts to the ventricles, so the atria and ventricles depolarize independently.

Plain: No signal gets from the top of the heart to the bottom, so the two halves beat on their own, out of step.

In complete AV block the atria and ventricles fire independently. The slow backup rhythm that keeps the patient alive is unreliable, so pacing is the priority.

Torsades de pointestor-SAHD duh PWANT

Polymorphic ventricular tachycardia with QRS complexes that twist around the baseline, arising on a prolonged QT interval.

Plain: A dangerous fast rhythm where the ECG spikes seem to twist around the line. It is linked to a long QT.

Torsades de pointes is a form of ventricular tachycardia tied to a prolonged QT. Magnesium is the treatment, along with correcting low potassium, and defibrillation if a pulse is lost.

TroponinTROH-poh-nin

A cardiac contractile protein released into the blood when myocardium is injured; a serial rise confirms myocardial infarction.

Plain: A substance that leaks into the blood when heart muscle is hurt. A rising level helps confirm a heart attack.

Troponin leaks from injured heart cells, so a blood test that shows it rising over time is a key way to confirm a heart attack, especially an NSTEMI.

U waveYEW-wayv

A small deflection following the T wave; prominent U waves are a classic sign of hypokalemia.

Plain: A tiny extra bump that sometimes follows the T bump. Clear U bumps are a common sign of low potassium.

V4Rvee-four-ARR

A right-sided precordial electrode mirroring V4, used to detect right ventricular infarction, usually in the setting of an inferior STEMI.

Plain: An extra sticker put on the right side of the chest to check if the right side of the heart is hurt during a heart attack.

In an inferior heart attack, V4R shows if the right ventricle is affected. That matters because those patients depend on filling pressure, so nitroglycerin can drop their blood pressure dangerously.

VFvee-EFF

Disorganized, chaotic ventricular electrical activity with no effective contraction or output; a shockable cardiac arrest rhythm.

Plain: The bottom of the heart quivers instead of pumping, so no blood moves. It is a cardiac arrest that needs a shock.

In ventricular fibrillation the ventricles twitch randomly instead of squeezing, so there is no blood flow. Immediate CPR and defibrillation are the treatment.

VTvee-TEE

A wide-complex tachycardia originating in the ventricles, occurring with or without a pulse; a life threat treated as an emergency.

Plain: A fast heartbeat coming from the bottom of the heart. It is an emergency and can be very dangerous.

Ventricular tachycardia is a wide, fast run of beats from the ventricles. The pulse check decides everything: a pulse means cardioversion or amiodarone, no pulse means CPR and defibrillation.

Wellens syndromeWELL-enz

Biphasic or deep symmetric T wave inversion in V2 to V3 signalling critical proximal left anterior descending artery stenosis.

Plain: A warning T-bump pattern in the front chest leads that points to a serious narrowing in a major heart artery.

Wellens shows deep or biphasic T wave changes in V2 and V3, often when the patient is pain free. It flags a critical blockage in the left anterior descending artery and needs urgent cardiology.

Wenckebach (Mobitz I)VENK-uh-bahk

Mobitz I second degree AV block: progressive PR prolongation until an atrial impulse is dropped, then the cycle repeats; usually AV nodal and benign.

Plain: A partial block where each beat takes a little longer to get through until one beat is skipped, then the pattern starts over.

In Wenckebach, or Mobitz I, the PR interval stretches beat by beat until a QRS is skipped. It is usually a benign block at the AV node and rarely needs treatment on its own.

WPWwoolf-PAR-kin-sun-WYTE

Wolff-Parkinson-White: a congenital accessory pathway causing ventricular pre-excitation (short PR, delta wave) and predisposing to re-entrant tachycardias.

Plain: A heart born with an extra electrical shortcut that can set off dangerously fast heartbeats.

In WPW an accessory pathway bypasses the normal gatekeeper node, showing a short PR and a delta wave. Standard AV-blocking drugs can be dangerous if the patient is also in atrial fibrillation.

Alveolar plateaual-VEE-oh-lur pla-TOH

Phase III of the capnogram, the near-flat segment of alveolar gas exhalation whose endpoint gives the EtCO2 value.

Plain: The flat top of the breathing wave, where air from deep in the lungs is measured.

The alveolar plateau is phase III of the capnogram. It slopes gently upward and its endpoint gives the end-tidal CO2. A steep, slurred plateau points to obstructed airways.

ApneaAP-nee-uh

Cessation of spontaneous respiration.

Plain: A pause or complete stop in breathing.

Auto-PEEPAW-toh peep

Air trapping (breath stacking) from incomplete exhalation before the next breath, raising intrathoracic pressure and impairing venous return.

Plain: Trapped air that builds up in the lungs when a person cannot fully breathe out before the next breath starts.

Auto-PEEP, or breath stacking, happens when expiration is cut short. The trapped gas raises pressure in the chest, which can lower blood pressure. The fix is more time to exhale.

BronchospasmBRONG-koh-spaz-um

Constriction of bronchial smooth muscle that narrows the airways, causing wheeze and prolonged expiration, as in asthma and anaphylaxis.

Plain: A sudden tightening of the muscles around the airways, which narrows them and makes it hard to breathe out.

Bronchospasm is the airway squeezing seen in asthma and anaphylaxis. On capnography it produces a shark-fin waveform, and it eases as bronchodilators take effect.

CapnogramKAP-noh-gram

The capnography waveform for a single breath; its morphology (a normal square wave, a shark-fin, a curare cleft) is as diagnostic as the numeric value.

Plain: The wavy line drawn for each breath. Its shape tells the team as much as the number does.

A normal capnogram looks like a box with four phases. A shark-fin shape means airway obstruction, and a notch in the plateau (curare cleft) means the patient is breathing against the machine.

Capnographykap-NOG-ruh-fee

Continuous measurement of exhaled carbon dioxide, displayed as a numeric value (EtCO2) and a waveform, reflecting ventilation, perfusion, and metabolism.

Plain: A way to measure the carbon dioxide a person breathes out, shown as both a number and a wavy line.

Capnography tracks exhaled CO2 breath by breath. The waveform and the number together reveal how well a patient is breathing, how well CPR is working, and whether a breathing tube is in place.

Carboxyhemoglobinkar-bok-see-HEE-muh-gloh-bin

Hemoglobin bound to carbon monoxide instead of oxygen; it cannot transport oxygen and is misread as oxyhemoglobin by a standard pulse oximeter.

Plain: The blood's oxygen carrier stuck to carbon monoxide instead of oxygen. It cannot carry oxygen and fools the finger clip.

In carbon monoxide poisoning, carboxyhemoglobin builds up. A standard pulse oximeter reads it as if it were oxygen, so the SpO2 can look normal while the patient is starved of oxygen.

CO-oximetrysee-oh-ok-SIM-uh-tree

Multi-wavelength oximetry that distinguishes oxyhemoglobin, carboxyhemoglobin, and methemoglobin, unlike a two-wavelength pulse oximeter.

Plain: A special oxygen sensor that can tell apart normal and damaged forms of the blood's oxygen carrier, unlike a basic finger clip.

COPDsee-oh-pee-DEE

Chronic obstructive pulmonary disease: progressive airflow limitation from chronic bronchitis and emphysema, with air trapping and CO2 retention.

Plain: A long-term lung disease that narrows the airways and traps air, making it slow and hard to breathe out.

Chronic obstructive pulmonary disease covers chronic bronchitis and emphysema. It gives a shark-fin capnogram from air trapping and a tendency to hold onto carbon dioxide.

Curare cleftkoo-RAR-ee KLEFT

A notch in the alveolar plateau of the capnogram from a spontaneous inspiratory effort against the ventilator as neuromuscular blockade wanes.

Plain: A notch in the flat top of the breathing wave, showing a sleepy patient taking a breath on their own through the machine.

A curare cleft appears when a paralytic drug is wearing off and the patient breathes against the ventilator. It is a cue to give more sedation before more paralytic.

Dead spaceDED-spays

The portion of each breath that fills the conducting airways and never reaches gas-exchanging alveoli, so it carries no CO2.

Plain: Air that fills the breathing tubes but never reaches the parts of the lungs that trade gases, so it carries no carbon dioxide.

Dead space is the volume of each breath that sits in the windpipe and larger airways. Because it does not take part in gas exchange, it explains the flat zero start of the capnogram.

DyspneaDISP-nee-uh

The subjective sensation of breathlessness or difficult, laboured breathing.

Plain: The feeling of being short of breath or not able to get enough air.

EtCO2ee-tee-see-oh-TOO

End-tidal carbon dioxide: the partial pressure of CO2 at the end of exhalation, normally 35 to 45 mmHg, reflecting ventilation and perfusion.

Plain: The amount of carbon dioxide in the last bit of air a person breathes out. It shows how well they are breathing.

End-tidal CO2 is the peak reading of exhaled carbon dioxide. It reflects breathing, circulation, and metabolism at once, so a sudden fall can mean a lost airway, poor CPR, or shock.

Hypercapniahy-per-KAP-nee-uh

An elevated arterial carbon dioxide level, usually from inadequate alveolar ventilation.

Plain: Too much carbon dioxide built up in the blood, usually because a person is not breathing enough.

Hypercapnia happens when carbon dioxide is not cleared fast enough, often from slow or shallow breathing. It causes drowsiness and, if severe, unconsciousness.

Hypoventilationhy-poh-ven-tih-LAY-shun

Alveolar ventilation insufficient to clear CO2, producing a rising arterial carbon dioxide level.

Plain: Breathing too slowly or too shallowly to clear enough carbon dioxide, so it builds up.

Hypoxiahy-POK-see-uh

Deficient oxygen at the tissue level (hypoxia) or in arterial blood (hypoxemia) relative to metabolic demand.

Plain: Not enough oxygen reaching the body's tissues.

Hypoxia means the tissues are short of oxygen. It shows as low SpO2, confusion, fast breathing, and eventually a blue tinge, and it is a common driver of many emergencies.

Methemoglobinmet-HEE-muh-gloh-bin

Hemoglobin with iron oxidized to the ferric state, which cannot bind oxygen and pins the pulse oximeter near 85 percent.

Plain: A changed form of the blood's oxygen carrier that cannot carry oxygen well and makes the finger clip stick near 85 percent.

Methemoglobinemia is a state where hemoglobin is chemically altered and cannot release oxygen properly. It makes the SpO2 stick around 85 percent no matter the true oxygen level.

Oxyhemoglobinok-see-HEE-muh-gloh-bin

Hemoglobin bound with oxygen, the form that transports oxygen in arterial blood.

Plain: The oxygen carrier in red blood cells when it is loaded up with oxygen.

PEEPPEEP

Positive end-expiratory pressure: airway pressure maintained at end-exhalation to keep alveoli open and improve oxygenation.

Plain: A small amount of pressure kept in the lungs at the end of each breath to hold the tiny air sacs open.

PlethPLETH

The plethysmographic waveform from the pulse oximeter tracking pulsatile blood flow; a strong, regular pleth validates the SpO2 reading.

Plain: The pulse wave from the oxygen finger clip. A strong, steady wave means the oxygen number can be trusted.

The pleth, short for plethysmograph, rises and falls with each heartbeat. Its height tracks blood flow, so a weak or flat pleth warns that the SpO2 number may be unreliable.

Pulse oximetrypuls ok-SIM-uh-tree

Non-invasive measurement of arterial oxygen saturation by light absorption through a digit, also yielding a pulse rate and a plethysmograph.

Plain: A painless finger clip that shines light through the finger to estimate the oxygen in the blood.

Pulse oximetry measures oxygen saturation without a needle. It also produces a waveform, the pleth, whose strength shows whether the reading can be trusted.

SpO2ess-pee-oh-TOO

Peripheral oxygen saturation: the percentage of hemoglobin bound with oxygen, measured by pulse oximetry; normal is about 95 to 100 percent.

Plain: The percent of the blood's oxygen spots that are filled, measured by a clip on the finger. Around 95 to 100 is normal.

SpO2 is the pulse oximeter reading of oxygen saturation. It is quick and useful but lags real time and can be fooled by cold fingers, poor circulation, or carbon monoxide.

Ventilationven-tih-LAY-shun

The bulk movement of air in and out of the lungs that eliminates carbon dioxide; distinct from oxygenation.

Plain: Moving air in and out of the lungs, which clears carbon dioxide from the body.

Ventilation is about moving air, mainly to remove carbon dioxide. It is separate from oxygenation, which is about getting oxygen into the blood.

AfterloadAF-ter-lohd

The resistance the ventricle must overcome to eject blood, determined largely by systemic vascular resistance.

Plain: How hard the heart has to push to force blood out into the body.

Afterload is the pressure the heart must overcome to eject blood, set mostly by how tight the arteries are. High afterload makes the heart work harder.

Altered mental statusAWL-terd MEN-tul STAT-us

Any deviation from a patient's baseline cognition or arousal, such as confusion, lethargy, or agitation; a nonspecific sign with many causes.

Plain: Any change from a person's normal alertness or thinking, like confusion, sleepiness, or being agitated.

Blood pressureBLUD PRESH-ur

The pressure exerted by circulating blood on the arterial walls, expressed as systolic over diastolic (for example 120/80 mmHg).

Plain: The push of blood against the artery walls, written as the squeeze number over the resting number, like 120 over 80.

Blood pressure has a top number, the pressure while the heart squeezes, and a bottom number, the pressure while it rests. It is a quick window on how well circulation is holding up.

Cardiac outputKAR-dee-ak OWT-poot

The volume of blood the heart pumps per minute, the product of heart rate and stroke volume.

Plain: How much blood the heart pumps each minute. It depends on how fast and how hard the heart beats.

Cardiac output is heart rate multiplied by the amount pumped per beat. Too fast, too slow, or too weak a heart all cut it, which drops blood pressure and perfusion.

Cardiogenic shockkar-dee-oh-JEN-ik SHOK

Shock from pump failure, an inadequate cardiac output despite adequate volume, most often after a large myocardial infarction.

Plain: Shock caused by the heart being too weak to pump enough blood, often after a big heart attack.

Compensatorykom-PEN-suh-tor-ee

Physiologic responses that maintain perfusion during an insult, such as tachycardia and vasoconstriction in early shock, before decompensation.

Plain: The body's automatic backup responses that keep it going when something is wrong, like a fast heartbeat during blood loss.

A compensatory response is the body propping itself up. Sinus tachycardia during shock is compensatory, which is why you treat the cause and not the fast rate itself.

Hemodynamichee-moh-dy-NAM-ik

Relating to blood flow and the pressures that drive it; a hemodynamically unstable patient has inadequate perfusion or blood pressure.

Plain: Having to do with blood flow and blood pressure. An unstable patient's blood flow is failing.

Hemodynamics is the study of blood moving through the body. When someone is called hemodynamically unstable, it means their blood pressure and circulation are not keeping up.

Hs and TsAYCH-ez and TEEZ

The reversible causes of cardiac arrest, grouped as the Hs (hypoxia, hypovolemia, acidosis, potassium, hypothermia) and Ts (thrombosis, tamponade, tension pneumothorax, toxins).

Plain: A memory list of the fixable causes of cardiac arrest to check for and correct while trying to restart the heart.

The Hs and Ts are the common treatable causes of cardiac arrest, such as low oxygen, low volume, high or low potassium, and clots. Working through them can find a fix that restarts the heart.

Hypoperfusionhy-poh-per-FYOO-zhun

Inadequate blood flow to the tissues, causing cellular oxygen debt; the defining derangement of shock.

Plain: Not enough blood reaching the tissues, so organs are starved of oxygen. It is the main problem in shock.

Hypotensionhy-poh-TEN-shun

An abnormally low arterial blood pressure that may compromise organ perfusion.

Plain: Blood pressure that is lower than normal, which can mean organs are not getting enough blood.

Hypovolemiahy-poh-voh-LEE-mee-uh

A reduced circulating blood or fluid volume, from hemorrhage or dehydration, that lowers preload and blood pressure.

Plain: Too little fluid or blood in the body, from bleeding or dehydration, which lowers blood pressure.

Level of consciousnessLEV-ul uv KON-shus-nes

A patient's degree of arousal and awareness, from alert to unresponsive; a declining level of consciousness is a critical neurological sign.

Plain: How awake and aware a person is, from fully alert down to not responding. A drop is an important warning sign.

Perfusionper-FYOO-zhun

The delivery of oxygenated blood to the capillary beds of the tissues; its adequacy defines the presence or absence of shock.

Plain: The delivery of blood, and the oxygen it carries, to the body's tissues.

Perfusion is whether blood is actually reaching the organs. Good perfusion shows as warm skin, a normal mental state, and steady blood pressure; poor perfusion is a hallmark of shock.

PreloadPREE-lohd

The ventricular wall stretch at end-diastole, set by venous return; right ventricular infarction is preload-dependent.

Plain: How full the heart's rooms are with blood just before they squeeze. It depends on the blood coming back to the heart.

Preload is the stretch on the heart from the blood filling it before a beat. Right ventricular heart attacks depend heavily on preload, which is why nitroglycerin can be dangerous in them.

SepsisSEP-sis

Life-threatening organ dysfunction caused by a dysregulated host response to infection, often with distributive shock.

Plain: A dangerous, whole-body reaction to an infection that can drop blood pressure and harm organs.

ShockSHOK

A life-threatening state of inadequate tissue perfusion in which oxygen delivery fails to meet cellular metabolic demand.

Plain: A life-threatening state where the body's tissues are not getting enough blood and oxygen to work.

Shock is the failure of circulation to meet the body's needs. It has many causes, from blood loss to infection to a failing heart, and it needs the underlying cause treated fast.

Unstableun-STAY-bul

A patient with signs of inadequate perfusion (hypotension, altered mental status, ischemic chest pain, or acute heart failure) requiring immediate treatment.

Plain: A patient whose vital signs are failing, with signs like very low blood pressure or fading alertness. It needs fast action.

In rhythm and shock management, unstable means the problem is actively starving the body: low blood pressure, altered mental status, chest pain, or signs of shock. It changes the treatment plan.

Vital signsVY-tul SYNES

The objective measures of physiologic function: heart rate, respiratory rate, blood pressure, temperature, and oxygen saturation.

Plain: The core body measurements: heart rate, breathing rate, blood pressure, temperature, and oxygen level.

Acetaminophenuh-SEE-tuh-MIN-oh-fen

A non-opioid analgesic and antipyretic for mild to moderate pain and fever, with little anti-inflammatory effect.

Plain: A common medicine that lowers fever and eases mild pain, sold as Tylenol.

Acetaminophen (paracetamol) is a first-line, over-the-counter analgesic and antipyretic. Unlike NSAIDs it does not reduce inflammation or thin the blood, and overdose can cause serious liver injury.

Activated charcoalAK-tih-vay-ted CHAR-kohl

An oral adsorbent that binds many ingested toxins in the gut, given for select poisonings soon after ingestion in an alert patient.

Plain: A black powder swallowed after some poisonings that soaks up the poison in the gut.

Adenosineuh-DEN-oh-seen

An ultra-short-acting AV nodal blocker given as a rapid IV push to interrupt AV nodal re-entry and terminate SVT.

Plain: A very fast-acting drug pushed in quickly to briefly pause the heart's electrical relay and stop a fast rhythm.

Adenosine momentarily blocks the AV node, which can reset SVT back to a normal rhythm. It is given as a rapid IV push and its effect lasts only seconds. It is avoided in WPW with atrial fibrillation.

Amiodaroneam-ee-OH-duh-rohn

A class III antiarrhythmic for ventricular arrhythmias (VT, VF) and some atrial arrhythmias; given in shockable arrest after defibrillation.

Plain: A drug used to calm dangerous fast rhythms coming from the bottom of the heart.

Amiodarone is an antiarrhythmic given in stable VT and in cardiac arrest from VF or pulseless VT after shocks. It steadies the heart's electrical activity.

AspirinASS-pih-rin

An antiplatelet agent that irreversibly inhibits platelet aggregation, given early in suspected acute coronary syndrome.

Plain: A drug that makes blood platelets less sticky, given early in a suspected heart attack to slow clotting.

Aspirin stops platelets from clumping, which helps keep a partly blocked coronary artery from closing off completely. It is a standard early treatment in a suspected heart attack.

AtropineAT-roh-peen

An anticholinergic that blocks vagal input at the SA and AV nodes to increase heart rate in symptomatic bradycardia.

Plain: A drug that speeds up a dangerously slow heart by blocking the signals that slow it down.

Atropine is the first drug for symptomatic bradycardia. It works at the AV node, so it helps less with blocks lower in the system, where pacing is needed instead.

Beta-blockerBAY-tuh BLOK-er

A drug class that blocks beta-adrenergic receptors, reducing heart rate, contractility, and blood pressure.

Plain: A group of drugs that slow the heart and lower blood pressure by blocking adrenaline's effect on the heart.

Bronchodilatorbrong-koh-DY-lay-tor

A drug class that relaxes bronchial smooth muscle to widen the airways in obstructive lung disease (beta-2 agonists, anticholinergics).

Plain: A drug that relaxes and widens the airways, making it easier to breathe in asthma and COPD.

CalciumKAL-see-um

An electrolyte that stabilizes the cardiac membrane in severe hyperkalemia and counters calcium-channel-blocker toxicity; it does not lower potassium.

Plain: A mineral given to protect the heart when potassium is dangerously high, and to reverse some drug effects.

In high potassium, calcium is given first to stabilize the heart muscle and buy time while other treatments lower the potassium. It does not lower potassium itself.

Dexamethasonedek-suh-METH-uh-sohn

A corticosteroid that reduces airway inflammation in asthma, COPD, croup, and anaphylaxis. Acts over hours, not minutes.

Plain: A strong steroid that calms inflammation in asthma flares, croup, and severe allergic reactions.

DextroseDEK-strohs

Intravenous glucose (for example D10 or D50) to correct hypoglycemia when oral intake is unsafe.

Plain: Sugar given into a vein to quickly raise dangerously low blood sugar.

Diazepamdy-AZ-uh-pam

A benzodiazepine for seizures, sedation, and muscle spasm.

Plain: A calming and anti-seizure medicine, sold as Valium.

Diltiazemdil-TY-uh-zem

A non-dihydropyridine calcium channel blocker that slows AV nodal conduction for rate control in atrial fibrillation and flutter.

Plain: A drug that slows the heart's electrical gate, used to bring down a fast rate in atrial fibrillation.

Dimenhydrinatedy-men-HY-druh-nate

An antihistamine antiemetic for nausea, vomiting, and motion sickness. Frequently sedating.

Plain: A medicine for nausea and motion sickness, sold as Gravol, that can cause drowsiness.

Diphenhydraminedy-fen-HY-druh-meen

A first-generation H1 antihistamine for allergic reactions and, alongside epinephrine, anaphylaxis. Sedating.

Plain: An allergy medicine that eases itching, hives, and swelling, and often causes drowsiness.

DopamineDOH-puh-meen

A catecholamine infusion that raises heart rate and blood pressure by stimulating adrenergic receptors, used in bradycardia and shock.

Plain: A drug given by drip to raise a low heart rate or low blood sugar.

Epinephrineep-ih-NEF-rin

An adrenergic agonist causing vasoconstriction and increased cardiac output; the vasopressor in cardiac arrest and first-line for anaphylaxis.

Plain: A powerful drug that tightens blood vessels and revs up the heart, used in cardiac arrest and severe allergic reactions.

Epinephrine, also called adrenaline, is given in cardiac arrest every 3 to 5 minutes and is the treatment for anaphylaxis. It raises blood pressure and supports the heart.

FentanylFEN-tuh-nil

A potent, fast-acting synthetic opioid analgesic. Favoured when rapid onset and stable blood pressure matter; reversed by naloxone.

Plain: A very strong, fast-acting painkiller, many times stronger than morphine.

Fentanyl is a synthetic opioid far more potent than morphine, with a fast onset and short duration. It causes less histamine release, so it tends to be more haemodynamically stable.

Furosemidefyoo-ROH-suh-myde

A loop diuretic that offloads excess fluid, used in fluid-overload states such as some pulmonary edema.

Plain: A water pill that makes the body pass extra fluid, used when fluid backs up in the lungs.

GlucagonGLOO-kuh-gon

A hormone that raises blood glucose by mobilizing hepatic glycogen, given for hypoglycemia without IV access; also used in beta-blocker overdose.

Plain: An injected hormone that tells the body to release stored sugar, used when a low-sugar patient cannot swallow.

HeparinHEP-uh-rin

An anticoagulant that prevents clot propagation in myocardial infarction and other thrombotic conditions. It does not dissolve existing clot.

Plain: A blood thinner that helps stop new clots from forming.

Hydroxocobalaminhy-DROK-so-koh-BAL-uh-min

A cyanide antidote that binds cyanide into vitamin B12, given for smoke-inhalation cyanide toxicity. Tints the skin and urine red.

Plain: An antidote for cyanide poisoning, which can happen after breathing thick smoke in a fire.

Hydroxocobalamin treats cyanide poisoning, a real risk in closed-space fire smoke. It binds cyanide into cyanocobalamin (vitamin B12), which is cleared in the urine, and often tints the skin and urine deep red.

Ibuprofeneye-byoo-PROH-fen

A nonsteroidal anti-inflammatory drug (NSAID) for pain, fever, and inflammation.

Plain: A common medicine for pain, fever, and swelling, sold as Advil or Motrin.

Ibuprofen is an over-the-counter NSAID that reduces pain, fever, and inflammation. It can irritate the stomach and affect the kidneys, so it is used with caution in some patients.

Ipratropiumip-ruh-TROH-pee-um

An inhaled anticholinergic bronchodilator, given with salbutamol to relieve bronchospasm in asthma and COPD.

Plain: An inhaled medicine that helps open the airways, often used together with salbutamol.

KetamineKEET-uh-meen

A dissociative analgesic and anaesthetic that tends to preserve airway reflexes and blood pressure; also used for agitation and severe asthma.

Plain: A drug that blocks pain and can sedate, while usually keeping breathing and blood pressure steady.

Ketamine produces dissociative analgesia and is used for pain, procedural sedation, severe agitation, and refractory asthma. It generally maintains respiratory drive and supports blood pressure, which is useful in trauma.

Ketorolackee-TOR-oh-lak

A parenteral NSAID for moderate to severe pain, an opioid-sparing analgesic that does not cause sedation or respiratory depression.

Plain: A strong anti-inflammatory painkiller given by needle, without the drowsiness of opioids.

Lorazepamlor-AZ-uh-pam

A benzodiazepine for seizures (status epilepticus) and agitation, longer-acting than midazolam.

Plain: A calming medicine used to stop seizures and ease severe anxiety.

Magnesiummag-NEE-zee-um

An electrolyte given intravenously to treat torsades de pointes, refractory bronchospasm, and eclampsia.

Plain: A mineral given as a drug to treat the twisting rhythm called torsades and severe asthma.

Magnesium is the specific treatment for torsades de pointes and is also used in eclampsia and severe asthma. Low magnesium often goes hand in hand with low potassium.

Methylprednisolonemeth-il-pred-NISS-oh-lohn

A parenteral corticosteroid for asthma and COPD exacerbations and anaphylaxis. Delayed onset, so it supports rather than replaces first-line care.

Plain: A steroid given to calm severe inflammation in asthma and allergic reactions.

Midazolammih-DAZ-oh-lam

A short-acting benzodiazepine for seizures, sedation, and agitation. Can depress respiration and blood pressure.

Plain: A fast, short-acting calming and anti-seizure medicine.

MorphineMOR-feen

An opioid analgesic for moderate to severe pain. Can cause hypotension and respiratory depression; reversed by naloxone.

Plain: A strong painkiller made from opium, used for severe pain.

Morphine is a benchmark opioid analgesic. It relieves severe pain but can cause respiratory depression, hypotension, and nausea, and its effects are reversed by naloxone.

Naloxonenuh-LOK-sohn

An opioid antagonist that reverses opioid-induced respiratory depression; its short duration may require repeat dosing.

Plain: A drug that reverses an opioid overdose, quickly bringing back normal breathing.

Naloxone blocks opioids at their receptors, reversing the slowed breathing of an overdose. Its effect can wear off before the opioid does, so the patient must be watched.

Nitroglycerinny-troh-GLIH-suh-rin

A nitrate vasodilator that lowers preload and myocardial oxygen demand to relieve ischemic chest pain; avoided in RV infarction and hypotension.

Plain: A drug that widens blood vessels to ease chest pain by lowering how hard the heart has to work.

Nitroglycerin relaxes blood vessels, easing cardiac chest pain. It is avoided in right ventricular heart attacks because those patients depend on filling, and it can drop their blood pressure.

Nitrous oxideNY-truss OK-syde

An inhaled analgesic gas, delivered as a self-administered 50/50 nitrous oxide and oxygen mix (Entonox) for short-term pain relief.

Plain: A breathe-in gas that dulls pain, sometimes called laughing gas.

Norepinephrinenor-ep-ih-NEF-rin

A vasopressor infusion that raises blood pressure by vasoconstriction, a first-line agent for shock in advanced and critical care scopes.

Plain: A powerful drip medicine that tightens blood vessels to raise dangerously low blood pressure.

Normal salineNOR-mul SAY-leen

0.9% sodium chloride, an isotonic crystalloid for volume replacement and to keep an IV line patent.

Plain: Salt water given into a vein to replace lost fluid and keep an IV line open.

Ondansetronon-DAN-suh-tron

A 5-HT3 receptor antagonist antiemetic for nausea and vomiting, with minimal sedation.

Plain: A medicine that stops nausea and vomiting, with little drowsiness.

Oral glucoseOR-ul GLOO-kohs

A fast-acting oral carbohydrate for conscious hypoglycemia in a patient able to protect their own airway.

Plain: A sugar gel or tablets given by mouth to bring up low blood sugar in someone awake enough to swallow.

OxygenOK-sih-jen

A medical gas given to correct hypoxia, titrated to oxygen saturation. It has indications and cautions, and is not given routinely to everyone.

Plain: Extra oxygen given to a patient who is not getting enough, through a mask or nasal prongs.

Procainamideproh-KAY-nuh-myde

A class Ia antiarrhythmic (sodium channel blocker) used for stable wide-complex tachycardias and atrial fibrillation in WPW.

Plain: A drug used for some wide, fast heart rhythms.

Rocuroniumroh-kyoo-ROH-nee-um

A non-depolarizing neuromuscular blocker (paralytic) for rapid sequence intubation. Mandates sedation and ventilation; a critical care skill.

Plain: A paralyzing drug that relaxes all muscles so a breathing tube can be placed.

Salbutamolsal-BYOO-tuh-mol

A short-acting beta-2 agonist bronchodilator that relaxes airway smooth muscle in asthma and COPD; also shifts potassium intracellularly.

Plain: An inhaled drug that relaxes tight airway muscles, opening the airways in asthma and COPD.

Salbutamol, known as albuterol in the United States, is a fast-acting bronchodilator. It is inhaled to relieve wheezing and is also used to help shift potassium in high-potassium states.

Sodium bicarbonateSOH-dee-um by-KAR-buh-nate

A buffer that raises blood pH, used in specific poisonings (tricyclic overdose), severe hyperkalemia, and some prolonged arrests.

Plain: A medicine that reduces acid in the blood, used in certain overdoses and long arrests.

Ticagrelorty-KAG-reh-lor

An antiplatelet (P2Y12 inhibitor) given with aspirin in acute coronary syndrome. Clopidogrel (Plavix) is a related agent.

Plain: A blood-thinning tablet given with aspirin in a heart attack to keep platelets from clumping.

Tranexamic acidtran-eks-AM-ik

An antifibrinolytic that stabilizes formed clots, given early in major traumatic hemorrhage and some severe bleeds.

Plain: A medicine that helps stop heavy bleeding by keeping clots from breaking down.

Alveolial-VEE-oh-ly

The terminal air sacs of the lungs where gas exchange occurs, oxygen diffusing into the blood and carbon dioxide out.

Plain: The tiny air sacs deep in the lungs where oxygen enters the blood and carbon dioxide leaves.

AtriumAY-tree-um

One of the two upper cardiac chambers that receive returning venous blood and deliver it to the ventricles.

Plain: One of the two upper rooms of the heart that collect returning blood and pass it down.

Circumflex arterySUR-kum-fleks

The left circumflex artery, a branch of the left main that wraps around to supply the lateral wall of the left ventricle.

Plain: An artery that curves around to feed the side wall of the heart.

Coronary arteryKOR-uh-nair-ee AR-tuh-ree

One of the epicardial arteries that perfuse the myocardium itself; atherosclerotic occlusion of one produces a myocardial infarction.

Plain: One of the blood vessels on the surface of the heart that feed the heart muscle itself with oxygen.

The heart cannot use the blood inside its chambers to feed its own muscle, so the coronary arteries wrap around it. A blockage in one is what causes a heart attack.

LADell-ay-DEE

The left anterior descending artery, supplying the anterior wall and septum; occlusion causes an anterior STEMI, the widowmaker when proximal.

Plain: A major artery down the front of the heart. A blockage here causes a front-wall heart attack.

Myocardiummy-oh-KAR-dee-um

The middle, muscular layer of the heart wall whose contraction pumps blood.

Plain: The muscle wall of the heart that squeezes to pump blood.

RCAarr-see-AY

The right coronary artery, supplying the inferior wall and, in most people, the SA and AV nodes; occlusion causes an inferior STEMI.

Plain: The artery that feeds the bottom of the heart. A blockage here causes a bottom-wall heart attack.

VentricleVEN-trih-kul

One of the two lower cardiac chambers; the right pumps to the pulmonary circulation, the left to the systemic circulation.

Plain: One of the two lower rooms of the heart. They do the main pumping to the lungs and the body.

Cardioversionkar-dee-oh-VER-zhun

Delivery of a shock synchronized to the R wave to convert an unstable organized tachyarrhythmia to sinus rhythm without inducing VF.

Plain: A shock timed to the heartbeat that turns an unstable fast rhythm back to normal.

Synchronized cardioversion times the shock to the R wave to avoid triggering a worse rhythm. It is used for unstable patients in rhythms like SVT, atrial fibrillation, and VT with a pulse.

Cath labKATH lab

The cardiac catheterization suite where coronary angiography and percutaneous intervention (angioplasty and stenting) reopen an occluded artery.

Plain: The hospital room where blocked heart arteries are found and reopened using thin tubes threaded through a blood vessel.

The cardiac catheterization lab is where a STEMI is definitively treated. A catheter is guided to the blocked artery and a balloon and stent reopen it, restoring blood flow.

CPRsee-pee-ARR

Cardiopulmonary resuscitation: external chest compressions and ventilations that maintain circulation and oxygenation during cardiac arrest.

Plain: Pushing on the chest and giving rescue breaths to keep blood and oxygen moving when the heart has stopped.

Cardiopulmonary resuscitation manually pumps the heart and supplies oxygen during cardiac arrest. High-quality compressions with minimal pauses are the core of survival.

Defibrillationdee-fib-ril-AY-shun

Delivery of an unsynchronized electrical shock to depolarize the myocardium and terminate a shockable arrest rhythm (VF or pulseless VT).

Plain: An electric shock that resets a chaotic, life-threatening heart rhythm like VF.

Defibrillation delivers a large shock to stop the heart's chaotic activity, giving its natural pacemaker a chance to restart an organized rhythm. It only works on VF and pulseless VT.

Extubationeks-too-BAY-shun

Removal of an endotracheal tube from the trachea; inadvertent extubation is signalled by an abrupt loss of the capnography waveform.

Plain: Taking a breathing tube out of the windpipe.

Intubationin-too-BAY-shun

Insertion of an endotracheal tube into the trachea to secure the airway and enable controlled ventilation; placement is confirmed by capnography.

Plain: Placing a breathing tube through the mouth into the windpipe to protect the airway and help a person breathe.

Intubation secures the airway with an endotracheal tube. Capnography is used to confirm the tube is in the windpipe and to keep watching that it stays there.

IVeye-VEE

Intravenous: administration of fluids or medication directly into a vein through a cannula, giving immediate systemic access.

Plain: A small tube placed in a vein to give fluids or medicine straight into the bloodstream.

Reperfusionree-per-FYOO-zhun

Restoration of blood flow to ischemic tissue, such as reopening an occluded coronary artery in a STEMI.

Plain: Bringing blood flow back to tissue that was cut off, like reopening a blocked heart artery.

Transcutaneous pacingtranz-kew-TAY-nee-us PAY-sing

External electrical stimulation through chest pads to capture and drive the ventricles in symptomatic bradycardia or high-grade AV block.

Plain: Using pads on the chest to send electrical pulses that drive the heart when it beats too slowly on its own.

Transcutaneous pacing sends timed impulses through the skin to force the heart to beat at a set rate. It is used for symptomatic bradycardia or high-grade heart block when drugs fail.

Vagal maneuverVAY-gul muh-NOO-ver

A technique such as the Valsalva maneuver that raises vagal tone to slow AV nodal conduction, the first-line attempt to terminate stable SVT.

Plain: A trick like bearing down hard that uses a nerve to slow the heart, tried first for a fast rhythm called SVT.

Acuteuh-KEWT

Of sudden onset and short duration, often severe; the opposite of chronic.

Plain: Coming on suddenly and often severe or short-lived, the opposite of long-lasting.

Asymptomaticay-simp-toh-MAT-ik

Producing no symptoms, even when a condition is demonstrable on examination or testing.

Plain: Showing no symptoms, even though a test or monitor finds a condition.

BaselineBAYS-lyne

The isoelectric reference line of a tracing between deflections, or a patient's usual physiologic state used for comparison.

Plain: The flat resting line on a monitor between waves, or a person's normal state used for comparison.

Baseline has two senses here. On the ECG it is the flat isoelectric line the waves rise from and return to; clinically it is the patient's usual condition before this problem.

Benignbih-NYNE

Not harmful or progressive; a benign finding carries little clinical threat.

Plain: Not harmful or dangerous. A benign finding does not need urgent treatment.

Bilateralby-LAT-uh-rul

Occurring on or affecting both sides of the body or a paired structure, such as both lungs.

Plain: Happening on both sides of the body, like both lungs or both arms.

ChronicKRON-ik

Persisting over a long period, months to years; the opposite of acute.

Plain: Lasting a long time, over months or years, the opposite of sudden.

Contraindicationkon-truh-in-dih-KAY-shun

A condition that makes a treatment inadvisable because its risk of harm outweighs the benefit in that patient.

Plain: A reason not to use a treatment because it could harm the patient in their situation.

A contraindication is a red flag against a treatment. For example, right ventricular heart attack is a contraindication to nitroglycerin because it can crash the blood pressure.

Edemauh-DEE-muh

Accumulation of excess fluid in the interstitial tissues, causing swelling, as in peripheral or pulmonary edema.

Plain: Swelling caused by fluid building up in the body, often in the legs or lungs.

Indicationin-dih-KAY-shun

A clinical circumstance that justifies the use of a particular test or treatment.

Plain: A reason to use a treatment: the situation where it is the right choice.

Occlusionuh-KLOO-zhun

Complete obstruction of a vessel or hollow structure; coronary occlusion produces a STEMI.

Plain: A complete blockage of a blood vessel or airway.

An occlusion is a full blockage. A coronary occlusion cuts blood flow to heart muscle and causes a STEMI, so time to reopening it is critical.

Refractoryrih-FRAK-tuh-ree

Resistant to standard treatment, requiring escalation or an alternative approach.

Plain: Not responding to the usual treatment, so a stronger or different one is needed.

Reversiblerih-VER-sih-bul

Capable of being corrected, such as a reversible cause of cardiac arrest that, once treated, can restore circulation.

Plain: Able to be undone or fixed, such as a cause of cardiac arrest that can be corrected to restart the heart.

Symptomaticsimp-toh-MAT-ik

Producing clinical symptoms, such as dizziness, chest pain, or dyspnea; symptomatic conditions generally warrant treatment.

Plain: Actually making the patient feel unwell, with things like dizziness, chest pain, or trouble breathing.

Symptomatic means the condition is producing complaints, which usually raises the urgency. A symptomatic bradycardia needs treatment, while an asymptomatic one may just be watched.

SyncopeSING-kuh-pee

A transient loss of consciousness from a brief fall in cerebral perfusion, with spontaneous recovery.

Plain: Fainting: a brief blackout caused by a short drop in blood flow to the brain.

Syncope is a passing faint from too little blood reaching the brain. Causes range from harmless to serious, including slow or fast heart rhythms.