In medicine, pulsus bisferiens, or biphasic pulse, is a sign where, on palpation of the pulse, a double peak per cardiac cycle can be appreciated. Biphasic means striking twice. Classically, it is detected when aortic insufficiency exists in association with aortic stenosis, but may also be found in isolated but severe aortic insufficiency, and hypertrophic obstructive cardiomyopathy.

A circuit for generating a biphasic voltage pulse to restore rhythm to a fibrillating heart, the circuit utilizing a capacitor for providing the voltage pulse. The circuit further comprises first and second thyristors to regulate the voltage and first and second electrodes to apply the regulated voltage to the fibrillating heart. The circuit further comprises an output sensing circuit that senses the exponential decay of the capacitor and signals a control circuit to switch the thyristors such that after one thyristor applies the voltage pulse to the heart in a first polarity, the other thyristor applies the voltage pulse in the opposite polarity. Therefore, substantially all energy in the capacitor is provided to the heart.

Normally arterial pulses are best felt in central arteries like brachial and carotid, but biphasic pulse is an exception to that and can be better felt in peripheral arteries like the radial artery. Another such pulse which can be felt better in peripheral arteries is biphasic pulse.