For example, the normal QRS complex in lead V1 does not contain a ... and the QRS duration is widened. A widened QRS duration occurs in the setting of a right bundle branch block, left bundle ...

Ventricular tachycardia refers to a wide QRS complex heart rhythm — that is, a QRS duration beyond 120 milliseconds — originating in the ventricles at a rate of greater than 100 beats per minute.

The goal of the trial was to evaluate cardiac resynchronization therapy (CRT) among patients with heart failure with narrow QRS complexes who were implanted with an implantable cardioverter ...