Can a bicuspid aortic valve (BAV) cause a murmur?

Bicuspid Aortic Valve and Heart Murmurs

Yes, a bicuspid aortic valve (BAV) can cause a heart murmur, typically presenting as a midsystolic murmur with an associated early systolic ejection sound. 1

Auscultation Findings in Bicuspid Aortic Valve

• Characteristic Sound: An early aortic systolic ejection sound heard during both inspiration and expiration is highly suggestive of a bicuspid aortic valve 1
• Murmur Characteristics:
  • Typically midsystolic (systolic ejection) murmur
  • Often crescendo-decrescendo in configuration
  • Usually heard best at the second right intercostal space (aortic area)
  • May vary in intensity from grade 1-6 depending on the degree of stenosis or regurgitation

Pathophysiology

BAV is the most common congenital cardiac malformation, affecting 1-2% of the population with a strong male predominance 2, 3. The murmur associated with BAV occurs due to:

1. Abnormal Flow Patterns: Even in the absence of significant stenosis, the abnormal valve anatomy creates turbulent blood flow across the valve 4, 5
2. Progressive Stenosis: BAV has a propensity to develop calcification and stenosis earlier than tricuspid valves, leading to increasing obstruction and a more prominent murmur over time 6
3. Regurgitation: BAV can also lead to aortic regurgitation, which would produce a different, diastolic decrescendo murmur 2, 3

Clinical Significance and Differentiation

• The presence of an early systolic ejection sound with a midsystolic murmur should raise suspicion for BAV, particularly when heard during both inspiration and expiration 1
• This differs from pulmonary valve stenosis, where the ejection sound is typically heard only in the pulmonic area and at the left sternal border during expiration 1
• A bicuspid aortic valve may be functionally normal or may lead to aortic stenosis or regurgitation, each with its characteristic murmur pattern 3

Associated Findings

When evaluating a patient with a suspected BAV murmur, be alert for:

• Signs of aortic stenosis: Slow-rising, diminished arterial pulse (parvus et tardus), soft or absent A2, or reversed splitting of S2 1
• Associated aortopathy: BAV is recognized as a syndrome incorporating both valve disorders and aortic wall abnormalities 2, 5
• Other congenital cardiac malformations: ventricular septal defect, patent ductus arteriosus, coarctation of the aorta 2

Clinical Pitfalls to Avoid

• Don't miss the ejection sound: The early systolic ejection sound is a key diagnostic clue for BAV and distinguishes it from other causes of systolic murmurs 1
• Don't assume all midsystolic murmurs are benign: While many midsystolic murmurs are innocent flow murmurs, the presence of an ejection sound should prompt further evaluation 1, 7
• Don't overlook associated aortopathy: Patients with BAV require assessment of the aorta due to the high prevalence of associated aortic dilation 5, 3

BAV is not just a valvular issue but a syndrome that may involve the aorta and other cardiac structures, making careful auscultation and appropriate follow-up essential for these patients.