This occurs at times of electrical “AV dissociation”, meaning with the P wave on the ECG overlaps with the QRS complex and thus atrial systole occurs simultaneously with ventricular systole.

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.

The murmur of an atrial septal defect is a systolic ... The murmur of a patent ductus arteriosus is continuous throughout systole and diastole since the aortic pressure (normally 120/80) is ...