Normal ECG Normal variant ECG Incorrect electrode placement Artifact

Right atrial abnormality / enlargement Left atrial abnormality / enlargement

Sinus rhythm Sinus arrhythmia Sinus bradycardia (<60 BPM) Sinus tachycardia (>100 BPM) Sinus pause or arrest Sinoatrial (SA) exit block Atrial premature complex (APCs) Atrial tachycardia Multifocal atrial tachycardia (MAT) Supraventricular tachycardia (SVT) Atrial flutter Atrial fibrillation (AFIB)

AV junctional premature complex (JPCs) AV junctional escape complex(es) AV junctional rhythm/tachycardia

Ventricular premature complex (VPCs) Ventricular parasystole Ventricular tachycardia (≥ 3 successive VPCs) (VT) Accelerated idioventricular rhythm (AIVR) Ventricular escape complex(es)/rhythm Ventricular fibrillation (VF)

AV block, 1° AV block, 2° - Mobitz type I (Wenckebach) AV block, 2° - Mobitz type II AV block 2:1 AV block, 3° (complete heart block) Wolff-Parkinson-White pattern (WPW) AV dissociation

Low voltage, limb leads Low voltage, precordial leads Left axis deviation (< - 30°) Right axis deviation (> + 100°) Electrical alternans

Left ventricular hypertrophy (LVH) Right ventricular hypertrophy (RVH) Combined ventricular hypertrophy

Brugada syndrome Digitalis toxicity Torsades de Pointes Hyperkalemia Hypokalemia Hypercalcemia Hypocalcemia Dextrocardia, mirror image Acute cor pulmonale/pulmonary embolus Pericardial effusion Acute pericarditis Hypertrophic cardiomyopathy (HCM) Central nervous system (CNS) disorder Hypothermia

Right bundle branch block, complete (RBBB) Right bundle branch block, incomplete (iRBBB) Left posterior fascicular block (LPFB) Left Anterior Fascicular Block (LAFB) Left bundle branch block, complete (LBBB) Left bundle branch block, incomplete (iLBBB) Aberrant conduction (including rate-related) Nonspecific intraventricular conduction disturbance

Anterolateral MI (acute or recent) Anterolateral MI (old or age indeterminate) Anterior or anteroseptal MI (acute or recent) Anterior or anteroseptal MI (old or age indeterminate) Lateral MI (acute or recent) Lateral MI (old or age indeterminate) Inferior MI (acute or recent) Inferior MI (old or age indeterminate) Posterior MI (acute or recent) Posterior MI (old or age indeterminate)

Early repolarization, normal variant Juvenile T waves, normal variant Nonspecific ST-T abnormalities ST-T changes suggesting myocardial ischemia ST-T changes suggesting myocardial injury ST-T changes suggesting electrolyte disturbance ST-T changes secondary to hypertrophy Prolonged QT interval Prominent U wave(s)

Atrial pacing Ventricular demand pacemaker (VVI), normal Dual-chamber pacemaker (DDD), normal Pacemaker malfunction, failure to capture Pacemaker malfunction, sensing abnormality Biventricular pacing (cardiac resynchronization therapy)