Pulsus Bisferiens: Two Distinct Systolic Peaks
Yes, pulsus bisferiens refers to two distinct peaks in the arterial pulse waveform during systole, separated by a mid-systolic dip or notch. This is a double-peaked pulse pattern, not two notches.
What It Actually Represents
Pulsus bisferiens is characterized by:
- Two systolic peaks in a single cardiac cycle
- A mid-systolic trough (dip) separating the two peaks
- The first peak occurs in early systole
- The second peak occurs in late systole
The term describes the peaks themselves, though the defining feature that makes them visible is the notch or cleft between them 1.
Clinical Significance and Pathophysiology
In hypertrophic obstructive cardiomyopathy (HOCM), pulsus bisferiens is a classic physical examination finding that correlates with the underlying hemodynamics 1. The carotid pulse shows this double pulsation pattern due to the dynamic left ventricular outflow tract obstruction 1.
The mechanism involves:
- First peak: Rapid early systolic ejection of blood
- Mid-systolic dip: Corresponds to the outflow tract obstruction
- Second peak: Late systolic flow augmentation or reflected wave return
Research demonstrates that in HOCM, the biphasic aortic flow pattern directly corresponds to the two peaks of pulsus bisferiens, with hemodynamic studies confirming this double-peaked pulse in both the left ventricular outflow tract and aorta 2.
Other Clinical Contexts
Pulsus bisferiens also occurs in:
- Severe aortic regurgitation with large stroke volumes 3
- Patent ductus arteriosus in neonates, where the first sharp peak results from augmented stroke volume and the second from reflected waves after rapid ductal runoff 4, 5
- Thoracoabdominal aortic aneurysms due to abnormal wave reflections 6
Clinical Pitfall
Don't confuse pulsus bisferiens with pulsus alternans (alternating strong and weak beats) or dicrotic pulse (where the second peak occurs in diastole after the dicrotic notch). In pulsus bisferiens, both peaks occur during systole.