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 ...

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 ...

The QRS rate for junctional rhythms is typically less than 100 beats/min, and the QRS complex usually narrow unless the baseline QRS has a bundle branch block. Sinus rhythm resumes with increased ...

The use of pacing therapy for sinus node dysfunction, AV block, and bundle branch block are discussed ... the presence of a nonphysiologic atrial rhythm and automatically switches the pacing ...