Pulsus bisferiens occurs in patients with significant aortic valve regurgitation. A double pulse is felt due to the backflow of blood in early diastole. The first carotid pulse felt is normal systole, while the second is actually early diastolic due to the regurgitating blood.
Most frequently caused by hemodynamically significant aortic regurgitation, pulsus bisferiens is detected by examining the carotid upstroke. Two pulsations are detected in systole. The first is caused by the pressure increase related to left ventricular ejection. The second systolic pulsation is caused by either arterial recoil reflected from the periphery, or early diastolic from the backflow of the regurgitated blood. The Valsalva maneuver or inhalation of amyl nitrate can precipitate pulsus bisferiens in some cases.
Pulsus bisferiens can also be seen in hypertrophic obstructive cardiomyopathy (HOCM), patent ductus arteriosus, arteriovenous fistulas and normal hearts in a hyperdynamic state.