Relationship Between Left Ventricular Deformation and Early Diastolic Intraventricular Pressure Difference During Rest and Exercise

抄録

Objective: The aim of this study was to investigate the mechanism underlying the increase in intraventricular pressure difference (IVPD) during exercise.
Background: Although left ventricular sucking force during early diastole plays an important role in exercise tolerance, the mechanism by which sucking force increases during exercise remains unclear.
Methods: Twenty-two healthy men (age range, 22-37 years) underwent echocardiography at rest and while performing “supine bicycle” exercises that included four workload stages at 25 W, 50 W, 75 W, and 100 W. IVPD was calculated with a one-dimensional Euler equation using color Doppler M-mode data, and its relationship with ventricular wall motion patterns was assessed.
Results: Peak IVPD observed at early diastole increased from 2.83±0.65 mmHg at rest to 5.31±0.78 mmHg at 100-W loading (p<0.001). Peak IVPD correlated positively with heart rate and cardiac output and negatively with isovolumic relaxation time and diastolic duration (p<0.001 for all). Only lengthening of circumferential strain during early diastole correlated with IVPD at rest (p=0.046). In all loading conditions, all deformation parameters except for left ventricular length strain significantly correlated with IVPD.
Conclusions: IVPD plays an important role in generating diastolic sucking force to adjust to loading conditions during exercise. At rest, only circumferential dilatation generated a pressure gradient, but during exercise, torsional deformation also played an important role in causing IVPD. These results provide new insight into diastolic function during exercise.