Association of left ventricular global area strain derived from resting 3D speckle-tracking echocardiography and exercise capacity in individuals undergoing treadmill exercise test.

Background: Left ventricular (LV) global area strain (GAS) is a novel index derived from resting 3D speckle-tracking echocardiography (STE), and its clinical significance has rarely been studied. We examined the association of LV GAS and exercise capacity in a health check-up population. Methods: We recruited 94 symptom-free participants (52.2 ± 11.7 years, 62.8% male) without substantial structural heart disease or coronary heart diseases who were undergoing a routine health examination. All participants underwent resting echocardiography and symptom-limited treadmill exercise test according to the Bruce protocol. Four strain parameters were obtained from the analysis, namely 3D GAS (GAS3d), global longitudinal strain, global circumferential strain, and global radial strain. Results: After multivariate analysis for factors of exercise time, we observed a significant association in LV GAS3d (P < 0.001). We divided participants into preserved and impaired exercise capacity groups according to the cutoff value of 8 metabolic equivalent of tasks. LV GAS3d (OR 1.24, 95% CI 1.10-1.39, P < 0.001) was an independent predictor of impaired exercise capacity and the optimal cut-off value was -19.96% at a sensitivity of 77.8% and at a specificity of 92.1%. LV GAS3d could improve the discriminatory power of exercise capacity in individuals with early mitral filling velocity to average mitral annulus velocity ratio (E/e') ≥ 8. Conclusions: LV GAS3d was significantly associated with exercise time and exhibited incremental predictive value on E/e' for exercise capacity in participants undergoing treadmill exercise test.

Effects of postsystolic shortening and diastolic dyssynchrony on myocardial work in untreated early hypertension patients.

OBJECTIVES: Myocardial work is estimated from noninvasive pressure-strain loop for advanced assessment of left ventricular function. Postsystolic shortening and diastolic dyssynchrony of left ventricle were noted early in hypertension. Their novel effects on myocardial work will be illustrated in this study. METHODS: We recruited 43 newly diagnosed hypertensive patients (mean age 51.3 ±â€Š12.5 years, 55.8% men) and 32 age-matched and sex-matched healthy individuals (mean age 52.7 ±â€Š10.5 years, 37.5% men) as control. Pressure-strain loop derived myocardial work incorporated global longitudinal strain from speckle tracking echocardiography with brachial artery cuff pressure. Postsystolic strain index (PSI) was defined by the percentage of postsystolic shortening over peak strain. Diastolic dyssynchrony was assessed by standard deviation of time to peak early diastolic strain rate (TDSr-SD) of 18 segments, and maximal difference of time to peak early diastolic strain rate (TDSr-MD) between any two segments. RESULTS: After multivariate regression analysis, global myocardial work index (GWI) was independently correlated with TDSr-SD (B = -0.498, P = 0.001) and TDSr-MD (B = -0.513, P = 0.001). Global myocardial constructive work (GCW) was independently correlated with TDSr-SD (B = -0.334, P = 0.025) and TDSr-MD (B = -0.397, P = 0.007). Global myocardial wasted work (GWW) was independently correlated with PSI (B = 0.358, P = 0.019). Global myocardial work efficiency (GWE) was lower in hypertensive patients than healthy control (P = 0.001). The untreated hypertensive patients were different from the healthy individuals with higher TDSr-SD, TDSr-MD, GWI, GCW, GWW, and PSI (all P < 0.05). CONCLUSION: In conclusion, the effect of diastolic dyssynchrony mainly influenced constructive work, whereas postsystolic shortening affected wasted work in early untreated hypertension.