Clinical Significance of Left Ventricular Torsional Parameters during Supine Bicycle Cardiopulmonary Exercise Echocardiography

ABSTRACT

BACKGROUND: Left ventricular (LV) torsion plays an important role in both LV systolic and diastolic function. Notwithstanding the fact that speckle tracking imaging echocardiography (STI) is a validated method to measure LV torsion, few data regarding the clinical significance of LV torsional parameters using STI on exercise capacity during exercise echocardiography were reported. METHODS: Fifty four participants completed the supine bicycle cardiopulmonary exercise echocardiography under a symptom-limited protocol. LV torsion was defined as the net difference between LV peak apical rotation, and basal rotation divided by LV diastolic longitudinal length. LV basal, and apical short-axis rotations at each stage were analyzed by STI. RESULTS: LV torsion measurement was feasible in 43/54 (80%) at peak exercise. The LV torsions were increased during exercise, and even until the recovery. Peak twisting, and untwisting velocities were significantly increased during exercise, but were decreased at recovery. As expected, baseline torsion was positively correlated with LV ejection fraction and baseline apical peak untwisting velocity has correlation with E/E' (r=0.50, p<0.01 and r=0.30, p<0.05, respectively). Interestingly, apical peak twisting velocity at peak exercise was significantly correlated with maximal O2 consumption and VO2 interval change (r=0.50, p<0.01 and r=0.33, p<0.05, respectively). CONCLUSION: It was feasible to measure LV torsion by STI at every step during exercise echocardiography, although the feasibility was relatively low at peak exercise. LV torsional parameters during exercise showed significant relations with exercise capacity as well as LV systolic and diastolic functions.