[Ultrasound stethoscope in the rapid assessment of left ventricular systolic function and valvular...

Recent technological advances enabled miniaturization of echocardiographic machines and construction of portable "ultrasound stethoscopes", which enable rapid two-dimensional and color-Doppler imaging and supplement clinical examination of the heart. We present the results of systematic assessment of these devices in comparison with standard echocardiographic machines.

We prospectively examined with both ultrasound stethoscopes and standard echocardiographic machines 60 patients referred to our laboratory for routine echocardiographic examination. Image quality (score: 1 to 4; best to worst), accuracy in qualitative evaluation of valvular regurgitation and left ventricular function (ejection fraction) were directly compared. Color Doppler assessment of valvular regurgitation was graded on a standard four point scale. A two or more point difference was considered major. Ejection fraction was estimated (the ultrasound stethoscope is not equipped with appropriate software).

Image quality was significantly worse in the case of ultrasound stethoscope (2.6 vs 2.1; p<0.0001). Major differences in the assessment of regurgitant jets were present in 3 cases (5%) (1 mitral and 2 tricuspid). The degree of agreement was good in the case of mitral and pulmonary regurgitation (kappa=0.61 and 0.74 respectively), very good in the case of aortic regurgitation (kappa=0.80) and moderate in the case of tricuspid regurgitation (kappa=0.48). The differences in the assessment of aortic and mitral regurgitant jets correlated with the image quality (p<0.05). A Bland-Altman graph comparing the results of ejection fraction assessment revealed good agreement between methods.

Results of the systematic evaluation of the use of ultrasound stethoscopes in the rapid evaluation of left ventricular systolic function and valvular regurgitation. Although image quality achieved with the hand-held stethoscope was worse, nevertheless it was adequate for the purpose of performing rapid limited assessment of cardiac and valvular function.