DDs

Atrial fibrillation with slow ventricular response

• Severe AV nodal disease

• Hypothermia

• Medications: Digoxin toxicity, Calcium-channel blocker / beta-blocker toxicity

Tachydysrhythmias

Narrow-complex regular rhythm:

• Sinus tachycardia

• Supraventricular tachycardia

• Atrial flutter

Narrow-complex irregular rhythm:

• Atrial fibrillation

• Atrial flutter with variable block

• Multifocal atrial tachycardia

Wide-complex regular rhythm:

• Ventricular tachycardia

• Sinus tachycardia with aberrant conduction

• SVT with aberrant conduction

• Atrial flutter with aberrant conduction

Wide-complex irregular rhythm:

• Atrial fibrillation with aberrant conduction (for example bundle branch block)

• Atrial flutter with variable block and aberrant conduction

• Multifocal atrial tachycardia with aberrant conduction

• Atrial fibrillation with WPW

• Polymorphic ventricular tachycardia / Torsades de Pointes

Leftward axis

• Left anterior fascicular block

• Left bundle branch block

• Inferior myocardial infarction

• Left ventricular hypertrophy

• Ventricular ectopy

• Paced beats

• Wolff-Parkinson-White syndrome

Low voltage

• Myxoedema

• Large pericardial effusion

• Large pleural effusion

• End-stage dilated cardiomyopathy

• Severe chronic obstructive pulmonary disease

• Severe obesity

• Infiltrative myocardial diseases (i.e. restrictive cardiomyopathy)

• Constrictive pericarditis

• Prior massive MI

• Low gain settings on ECG machine

Increased QRS Duration

• Hypothermia

• Hyperkalaemia

• WPW

• Aberrant intraventricular conduction (for example bundle branch block)

• Ventricular ectopy

• Paced beats

• Drugs, particularly those with sodium-channel blocking effects

Increased QT-interval (and QTc-interval)

• Hypokalaemia

• Hypomagnesaemia

• Hypocalcaemia

• Myocardial ischemia

• Elevated intracranial pressure

• Sodium-channel blockers

• Hypothermia

• Congenital prolonged QT syndrome

• Hypokalemia — the actual QT-interval is normal; the QT-interval appears prolonged because of the presence of fusion of the T-wave with a U-wave (a “T-U fusion complex”)

Poor R-wave progression (PRWP)

• Prior anteroseptal MI

• LVH

• Abnormally high placement of the mid-precordial electrodes

• Normal variant

Prominent R-wave in lead V1 (R/S ratio >1)

• WPW

• Posterior MI

• RBBB (or incomplete RBBB)

• Ventricular ectopy

• RVH

• Acute right ventricular dilatation (right ventricular “strain,” e.g. massive PE)

• Hypertrophic cardiomyopathy

• Progressive muscular dystrophy

• Dextrocardia

• Misplaced precordial electrodes

• Paediatric ECG

• Normal variant (rare)

Prominent T-wave

• Acute myocardial ischemia (i.e. hyperacute STEMI)

• Hyperkalaemia

• Acute pericarditis

• LVH

• Benign early repolarization

• Bundle branch block (LBBB / RBBB)

• Preexcitation syndromes

Rightward axis

• Left posterior fascicular block (LPFB)

• Lateral myocardial infarction

• Right ventricular hypertrophy (RVH)

• Acute lung disease (e.g. Pulmonary Embolus)

• Chronic lung disease (e.g. COPD)

• Ventricular ectopy

• Hyperkalaemia

• Sodium-channel blocker toxicity

• Normal in children or thin adults with a horizontally positioned heart

ST-segment elevation

• Acute myocardial infarction (AMI)

• Coronary vasospasm (Printzmetal’s angina)

• Pericarditis and myocarditis

• Benign early repolarisation (BER)

• Left bundle branch block (LBBB)

• Left ventricular hypertrophy (LVH)

• Ventricular aneurysm

• Brugada syndrome

• Ventricular paced rhythm

• Raised intracranial pressure (ICP)

• Left Ventricular Hypertrophy (LVH)

• Left Bundle Branch Block (LBBB)

• Anteroseptal MI

• Right ventricular MI

• Brugada syndrome

• Pulmonary embolism (PE, PTE)

• Extensive myocardial infarction

• Acute pericarditis

• Benign early repolarization (BER)

• Ventricular aneurysm

• Coronary vasospasm