Bipeaked Pulse: Clinical Associations and Diagnostic Significance
Primary Clinical Associations
A bipeaked (bisferiens) pulse is most characteristically seen in hypertrophic cardiomyopathy (HCM) with left ventricular outflow tract obstruction, and in combined aortic stenosis with aortic regurgitation. 1
The bisferiens pulse represents two distinct systolic peaks and reflects specific hemodynamic patterns:
In HCM with obstruction: The first peak occurs during early systolic ejection before the dynamic obstruction develops, and the second peak occurs in mid-to-late systole as the left ventricular outflow tract (LVOT) gradient increases 1
In combined aortic stenosis and regurgitation: The pulse contour reflects the rapid initial ejection through the stenotic valve followed by a secondary percussion wave 1
In isolated severe aortic regurgitation: A bipeaked pulse may occasionally be present due to the large stroke volume and rapid ventricular ejection, though this is less common than the classic "water-hammer" pulse 1
Diagnostic Approach When Bipeaked Pulse Detected
Initial Clinical Assessment
Obtain focused history for symptoms of syncope (especially exertional), angina, dyspnea, or exercise intolerance, as these indicate hemodynamically significant obstruction requiring urgent evaluation. 1
Key examination findings to differentiate causes:
Dynamic auscultation maneuvers are essential: The murmur of HCM increases with Valsalva maneuver and standing, while aortic stenosis murmurs decrease with these maneuvers 1, 2
Post-ventricular premature beat assessment: Murmurs from aortic stenosis increase after a compensatory pause, while HCM murmurs may not change significantly 1
Handgrip exercise: Increases murmurs of mitral regurgitation and aortic regurgitation but decreases the murmur of HCM 1
Mandatory Diagnostic Testing
Echocardiography is mandatory in all patients with a bipeaked pulse to identify asymmetric septal hypertrophy, systolic anterior motion (SAM) of the mitral valve, dynamic LVOT gradients, and valvular abnormalities. 1, 2, 3
Specific echocardiographic features to assess:
In HCM: Look for asymmetric septal hypertrophy (≥15 mm), SAM, LVOT gradient ≥30 mmHg at rest or with provocation, and associated aortic regurgitation (present in 20-30% of HCM patients) 1, 4, 5
In aortic stenosis: Measure aortic valve area, mean gradient (which best represents obstruction severity in AS), and assess for concurrent regurgitation 1, 6
Exercise stress echocardiography: Should be performed in symptomatic patients with HCM to assess for provokable gradients, as resting gradients may underestimate obstruction severity 1, 2
Critical Management Considerations
When HCM with Obstruction is Confirmed
Non-vasodilating beta-blockers titrated to maximum tolerated dose are first-line therapy for symptomatic HCM with obstruction. 2
If beta-blockers are insufficient or not tolerated, non-dihydropyridine calcium channel antagonists (verapamil or diltiazem) can be used, but with extreme caution due to risks of worsening obstruction and hypotension 2
Septal reduction therapy (surgical myectomy or alcohol septal ablation) should be considered for patients with persistent NYHA Class III-IV symptoms despite optimal medical therapy and resting or provoked gradients ≥50 mmHg 1, 2
When Combined Aortic Stenosis and HCM are Present
Hemodynamic catheterization with high-fidelity micromanometer-tip catheters is essential to accurately distinguish LVOT obstruction from valvular stenosis, as echocardiography may underestimate aortic valve area when LVOT obstruction reduces flow. 7, 6
In HCM, peak instantaneous and peak-to-peak gradients demonstrate excellent correlation (R² = 0.98) and can both be used to classify obstruction severity 6
In aortic stenosis, the mean gradient should direct clinical management rather than peak gradients 6
Address the LVOT obstruction first if it is the dominant pathology, as reducing the LVOT gradient may unmask the true severity of aortic stenosis 7
High-Risk Features Requiring Urgent Evaluation
Hospitalize patients with bipeaked pulse who have syncope (especially exertional), family history of sudden cardiac death, or significant structural heart disease for continuous cardiac monitoring and risk stratification. 1
Specific red flags:
Exertional syncope in HCM: Indicates inadequate cardiac output due to obstruction and/or arrhythmias, with high risk for sudden cardiac death 1
New atrial fibrillation: Can precipitate hemodynamic collapse in HCM due to loss of atrial contribution to ventricular filling 1
Ventricular arrhythmias: Even at modest rates can cause syncope in HCM patients 1
Common Pitfalls to Avoid
Do not assume isolated aortic stenosis: Always assess for HCM, as 20-30% of HCM patients have concurrent aortic regurgitation, and combined pathology requires different management 4, 5, 8
Do not rely on auscultation alone: Aortic regurgitant murmurs are audible in only 10% of HCM patients with Doppler-proven regurgitation 5, 8
Do not use vasodilators empirically: These can worsen LVOT obstruction in HCM and cause profound hypotension 1, 2
Do not overlook family screening: HCM is inherited, and first-degree relatives require echocardiographic screening 1