Impact of Transaortic Valve Flow Velocity on the Development of Systolic Heart Murmurs.

Background: Although cardiac auscultation plays an essential role in detecting valvular heart diseases, false-positive rates due to innocent heart murmurs remain a concern because accelerated transaortic valve blood flow can be a major contributor to systolic heart murmurs. In this study we investigated the effect of transaortic valve flow velocity on the development of systolic heart murmurs.

Methods and results: Cardiac auscultation was performed in 571 patients referred for echocardiography and systolic heart murmur was detected in 103 (18.0%). Maximum transaortic valve flow velocity was higher in patients with murmurs than in those without (2.02 vs. 1.34 m/s, P<0.001; area under the receiver operating characteristic curve, 0.82). A cutoff maximum transaortic flow velocity of 1.7 m/s predicted systolic heart murmurs (sensitivity, 65%; specificity, 88%). The incidence of heart murmur was associated with higher maximum transaortic valve flow velocity (<1.7 m/s, 7.3%; 1.7-2.5 m/s, 50.0%; >2.5 m/s, 73.5%). Multivariate analysis revealed the maximum transaortic valve flow velocity as an independent predictor of systolic heart murmurs (hazard ratio, 9.18; 95% confidence interval, 5.35-15.75; P<0.001).

Conclusions: Accelerated transaortic valve flow velocity is an important determinant of systolic heart murmurs. Systolic heart murmurs can be heard before the transaortic valve flow velocity reaches the clinically significant aortic stenosis criterion, which can constitute a considerable number of innocent heart murmurs.