Myocardial performance index as a measure of global left ventricular function improves following isometric exercise training in hypertensive patients

As the leading cause of cardiovascular disease and mortality, hypertension remains a global health problem. Isometric exercise training (IET) has been established as efficacious in reducing resting blood pressure (BP); however, no research to date has investigated its effects on the myocardial performance index (MPI). Twenty-four unmedicated hypertensive patients were randomized to 4 weeks of IET and a control period in a crossover design. Tissue Doppler imaging was used to acquire cardiac time intervals pre- and post-IET and during the control periods. IET significantly improved all measures of cardiac time intervals, including isovolumic relaxation time (83.1 ± 10.3 vs. 76.1 ± 11.2 ms, p = 0.006), isovolumic contraction time (84.8 ± 10.3 vs. 72.8 ± 6.4 ms, p < 0.001), ejection time (304.6 ± 30.2 vs. 321.4 ± 20.8 ms, p = 0.015) and the MPI (0.56 ± 0.09 vs. 0.47 ± 0.05, p < 0.001). This is the first study to demonstrate that IET significantly improves cardiac time intervals. These findings may have important clinical implications, highlighting the potential utility of IET in the management of cardiac health in hypertensive patients.