Therefore, when ventricular systole occurs in the setting of a long PR interval, the leaflets will be separated by a smaller distance, and the S1 sound will be softer. The converse is also true.

THE diagnosis of ventricular tachycardia without retrograde activation of the atrium is dependent upon the location of regular atrial activity that is independent of the faster ventricular rate.

During this time no electric systole could be produced by the pacemaker. Between 0.18 and 0.20 seconds the patient demonstrated 1 of 3 responses: the onset of transient ventricular tachycardia ...

Therefore, when ventricular systole occurs in the setting of a long PR interval, the leaflets will be separated by a smaller distance, and the S1 sound will be softer. The converse is also true.