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ULY CLINIC
ULY CLINIC
21 Septemba 2025, 23:24:10
Braunwald’s sign
Braunwald’s sign refers to the occurrence of a weak peripheral pulse rather than a strong one immediately after a premature ventricular contraction (PVC). This paradoxical finding is noted during cardiac monitoring and may indicate idiopathic hypertrophic subaortic stenosis (IHSS), also known as hypertrophic obstructive cardiomyopathy (HOCM).
Pathophysiology
In HOCM, the hypertrophied interventricular septum causes dynamic obstruction of the left ventricular outflow tract (LVOT).
After a PVC, the post-extrasystolic beat usually generates increased contractility (post-extrasystolic potentiation).
In patients with normal cardiac anatomy, this produces a stronger pulse after the PVC.
However, in HOCM, the enhanced contractility intensifies the outflow obstruction, reducing stroke volume and producing a weaker pulse — the essence of Braunwald’s sign.
Examination Technique
Patient positioning: Supine or semi-recumbent, relaxed.
Monitoring: Attach the patient to continuous ECG or cardiac monitor.
Observation: Watch for spontaneous or provoked PVCs.
Pulse assessment: Immediately palpate the carotid or radial artery following the PVC.
Interpretation: A weaker post-PVC pulse compared to the preceding normal beat suggests Braunwald’s sign.
Tip: Carotid palpation is preferred because it reflects central aortic pulse pressure more accurately.
Clinical utility
Diagnostic clue: Supports suspicion of hypertrophic obstructive cardiomyopathy, especially in patients with exertional syncope, dyspnea, or systolic murmurs.
Bedside differentiation: Helps distinguish HOCM from valvular aortic stenosis, where post-PVC pulses remain strong or augmented.
Adjunctive value: Useful when echocardiography is unavailable or as part of a comprehensive physical exam in cardiology training.
Differential Diagnosis
Condition | Pulse after PVC | Mechanism | Notes |
Hypertrophic obstructive cardiomyopathy | Weak | Post-extrasystolic potentiation increases LVOT obstruction, lowering stroke volume | Classic Braunwald’s sign |
Valvular aortic stenosis | Strong or unchanged | No dynamic obstruction; increased filling improves output | Post-PVC pulse is typically stronger |
Mitral valve prolapse | Variable | PVC may alter loading conditions but not outflow | No consistent change in pulse |
Dilated cardiomyopathy | Weak, but due to low contractility | Global systolic dysfunction, not dynamic LVOT obstruction | Different mechanism |
Normal heart | Strong | Increased inotropy after compensatory pause | Physiologic post-extrasystolic potentiation |
Management implications
Further evaluation: A positive Braunwald’s sign should prompt echocardiography to confirm HOCM and assess the degree of LVOT obstruction.
Medical therapy:
Beta-blockers (e.g., propranolol, metoprolol)
Non-dihydropyridine calcium channel blockers (e.g., verapamil)
Invasive therapy: Septal myectomy or alcohol septal ablation for refractory obstruction.
Lifestyle advice: Avoid dehydration, extreme exertion, and medications that decrease preload or afterload abruptly (e.g., nitrates).
Pediatric considerations
Braunwald’s sign can appear in adolescents with familial HOCM.
Early detection is important, as sudden cardiac death risk is higher in this age group.
Geriatric considerations
In older adults, Braunwald’s sign may be harder to appreciate due to vascular stiffness or concurrent aortic valve disease.
Combine with auscultation (harsh midsystolic murmur at left sternal border that increases with Valsalva).
Limitations
Requires the occurrence of PVCs during examination.
May be absent in non-obstructive hypertrophic cardiomyopathy or in patients on negative inotropic therapy.
Not pathognomonic; always confirm with imaging.
Patient Counseling
Explain that the sign is an observed change in pulse strength after an irregular heartbeat.
Reassure patients that further tests (echocardiogram, ECG) will clarify diagnosis and guide therapy.
Stress the importance of regular follow-up, avoidance of strenuous unmonitored exercise, and screening for first-degree relatives.
Conclusion
Braunwald’s sign is a valuable bedside finding pointing to hypertrophic obstructive cardiomyopathy. Recognizing its mechanism — a weaker pulse after a PVC due to accentuated LVOT obstruction — enhances clinical acumen, supports timely diagnosis, and underscores the importance of integrating physical signs with modern cardiac imaging.
References
Braunwald E, et al. Idiopathic hypertrophic subaortic stenosis: a clinical appraisal based on 64 patients. Circulation. 1964;29(Suppl):IV3–IV119.
Otto CM. Textbook of Clinical Echocardiography. 6th ed. Philadelphia: Elsevier; 2018.
Bonow RO, Mann DL, Zipes DP, Libby P. Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine. 12th ed. Philadelphia: Elsevier; 2022.
Maron MS, Rowin EJ, Olivotto I. Hypertrophic Cardiomyopathy: Diagnosis, Prognosis, and Management. Eur Heart J. 2021;42(34):3525–3537.