Non-invasive evaluation by thermistor plethysmography of left ventricular performance during dynamic exercise....

The purpose of this study was to evaluate the reliability of two non-invasive techniques (STI and echocardiography) in assessing cardiovascular response during exercise. STI were obtained using a new carotid pulse transducer (thermistor pulse) proved to be reliable in exercise recording. The study population included 12 male rowers (age 15-20 years), who performed supine bicycle exercise; STI and echocardiographic recording of left ventricle were simultaneously obtained at rest and continuously throughout the exercise period. A negative linear correlation (r=-0.782; p less than 0.001) was found between PEP (pre-ejection period) and %LVID (fractional shortening of left ventricle), reliable indexes of cardiac contractility measured by the two techniques. A lower, but significant correlation (r=0.643; p less than 0.001) was present between ETI (left ventricular ejection time corrected by heart rate) and SV (stroke volume) indexes of pump function. The present study shows that STI measured with this new technique, can be employed in evaluating left ventricular function in those patients in whom a good echocardiogram is difficult to record during exercise.