Any tachycardic rhythm with a left or right bundle branch block that is NOT ventricular tachycardia is considered "supraventricular tachycardia with aberrancy". This would even include sinus ...

If the QRS complex is widened and downwardly deflected in lead V1, a left bundle branch block is present ... The ECG strip below shows normal sinus rhythm, then atrial fibrillation with a rapid ...

AV, atrioventricular; bpm, beats per minute; LVH, left ventricular hypertrophy; RBBB, right bundle branch block ... complex usually narrow unless the baseline QRS has a bundle branch block. Sinus ...