Estimation of pressure gradients by auscultation: An innovative and accurate physical examination technique

Background Knowledge of pressure gradients across valves, arteries. and ven tricular septal defects (VSD) is important in patient management. It was de termined how well such gradients can be estimated by auscultation of a murm ur's frequencies. Methods In 151 patients with pulmonary stenosis (PS) (n = 77), aortic steno sis (AS) (n = 30), or VSD (n = 44), the aus cultation gradient was estimate d by a murmur's frequencies by use of an "auscultatory scale." The ausculta tion gradient was recorded before Doppler echocardiography was performed by a blinded cardiac sonographer. Results Auscultation correlated highly with Doppler echocardiography (Doppl er = 0.99 Auscultation + 7.12; r = 0.84, P < .0001). Agreement was good (me an difference [Auscultation - Doppler] = -6.8 +/- 15.8 mm Hg). In 95 patien ts (63%), agreement was within 10 mm Hg. Auscultation was more accurate whe n Doppler gradients were less than or equal to 60 mm Hg (r = 0.76, P < .000 1, vs r = 0.22, P not significant for <greater than>60 mm Hg; mean differen ce -2.6 +/- 10.6 mm Hg vs -16.5 +/- 20.9 mm Hg For > 60 mm Hg, P < .0001). Among lesions, PS showed the highest correlation, although agreement for PS , AS, and VSD was not significantly different. Isolated valvar PS showed ex cellent accuracy (r = 0.92, P < .0001; mean difference -5.6 +/- 8.9 mm Hg). Conclusions Auscultation of a murmur's frequency composition can estimate g radients accurately in most patients with PS (especially valvar PS), AS, or VSD, although it is less accurate for gradients >60 mm Hg. This innovative technique can improve diagnostic accuracy, thereby further substantiating the value of physical examination.