Does a premature ventricular contraction (PVC) increase the intensity of the aortic stenosis murmur?

Effect of PVC on Aortic Stenosis Murmur Intensity

Yes, the aortic stenosis murmur increases in intensity after a premature ventricular contraction (PVC). 1 This is a well-established clinical finding that can help differentiate aortic stenosis from other cardiac murmurs.

Physiological Mechanism

When a PVC occurs, the following beat (post-PVC beat) demonstrates:

• Increased stroke volume due to postextrasystolic potentiation
• Enhanced forward flow across the stenotic aortic valve
• Resulting increase in the intensity of the systolic ejection murmur

Clinical Evidence and Diagnostic Value

According to the ACC/AHA guidelines on valvular heart disease, murmurs originating at normal or stenotic semilunar valves (including aortic stenosis) increase in intensity during the cardiac cycle after a PVC 1. This response pattern helps distinguish aortic stenosis from other cardiac conditions:

• Increases after PVC: Murmurs of aortic stenosis and other semilunar valve stenoses
• No change or diminish after PVC: Murmurs due to atrioventricular valve regurgitation (e.g., mitral regurgitation)
• Become shorter after PVC: Mitral valve prolapse

Clinical Application

This finding has important diagnostic implications:

1. Differential diagnosis: The post-PVC augmentation of murmur intensity can help differentiate aortic stenosis from mitral regurgitation when the origin of a systolic murmur is unclear.

2. Severity assessment: Recent research suggests that post-PVC augmentation of the left ventricular-aortic pressure gradient may provide insights into the severity of aortic stenosis. In patients with low-flow, low-gradient aortic stenosis, the post-PVC augmentation in gradient is similar to that seen with dobutamine stress echocardiography 2.

3. Diagnostic specificity: In a recent observational study, the inability to generate a mean left ventricular-aortic gradient ≥40 mmHg after a PVC had 100% specificity for non-severe aortic stenosis 2.

Other Relevant Findings in Aortic Stenosis

While the post-PVC augmentation is useful, other clinical findings help characterize aortic stenosis:

• Slow rate of rise of the carotid pulse (high positive likelihood ratio for aortic stenosis) 3
• Mid to late peak intensity of the murmur 3, 4
• Decreased intensity of the second heart sound 3
• Radiation of the murmur to the carotid arteries (absence of this finding helps rule out aortic stenosis) 3

Clinical Pearls and Pitfalls

1. Pearl: The post-PVC augmentation of murmur intensity can be particularly useful when echocardiography is not immediately available or when findings are equivocal.

2. Pitfall: The intensity of aortic stenosis murmurs correlates with momentum transfer and body size, so loud murmurs may predict severe disease less reliably in larger patients 5.

3. Pearl: PVCs are common in patients with aortic stenosis, occurring in approximately one in four patients during cardiac catheterization 2, making this a practical diagnostic maneuver.

4. Pitfall: The presence of ventricular arrhythmias including PVCs tends to decrease after treatment of aortic stenosis, as demonstrated in patients following transcatheter aortic valve implantation 6.