Cardiac hemodynamics phenotypes and individual responses to training in coronary heart disease patients

In patients with coronary heart disease (CHD), individualized exercise training (ET) programs are strongly recommended to optimize peak oxygen uptake ( $\dot{V}$ O_2peak) improvement and prognosis. However, the cardiac hemodynamic factors responsible for a positive response to training remain unclear. The aim of this study was to compare cardiac hemodynamic changes after an ET program in responder (R) versus non-responder (NR) CHD patients.

A total of 72 CHD patients completed a 3-month ET program and were assessed by cycle ergometer cardiopulmonary exercise test (CPET: $\dot{V}$ O_2peak assessment) with impedance cardiography (ICG) for hemodynamic measurements before and after training. Cardiac hemodynamics (e.g., CO, CI, SV, ESV, EDV, and SVR) were measured by ICG during CPET. The R and NR groups were classified using the median change in $\dot{V}$ O_2peak (>the median for R and ≤the median for NR).

In the R group, $\dot{V}$ O_2peak (+17%, p < 0.001), CO, CI, SV, and HR increased by 17%, 17%, 13%, and 5%, respectively (p < 0.05) after the training program. In the NR group, $\dot{V}$ O_2peak, CO, CI, and SV increased by 0.5%, 5%, 8%, and 6%, respectively (p < 0.01). The SVR decreased in both groups (-19% in R and -11% in NR, p < 0.001).

Among CHD patients, the R group showed a better improvement in peak cardiac output via an increase in peak stroke volume and heart rate and a reduced systemic vascular resistance than the NR group. Different cardiac phenotype adaptations and clinical individual responses were identified in CHD patients according to the aerobic fitness responder's status.