Major causes of a wide ORS complex

Intrinsic intraventricular conduction delay

Left bundle branch block and variants

Right bundle branch block and variants

Other nonspecific IVCD patterns

Extrinsic intraventricular conduction delay

Hyperkalemia

Drug-induced - type I antiarrhythmic drugs and related sodium channel blocking agents (eg, tricyclic antidepressants and phenothiazines)

Ventricular beat

Premature

Escape

Paced

Ventricular preexcitation

Wolff-Parkinson-White (WPW) pattern and variants

Factitious

ECG unintentionally recorded at fast paper speeds (50 or 100 mm/s)

Wide QRS complex tachyarrhythmias

Ventricular tachycardia

Supraventricular tachycardia or atrial fibrillation or flutter with aberrant intraventricular conduction due to:

Bundle branch block

Atrioventricular bypass tract (preexcitation syndromes with orthodromic conduction)

Causes_of_wide_QRS_complex.htm

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