Background: Impaired exercise capacity is one of the most common clinical manifestations in patients with chronic heart failure (CHF). The severity of reduced exercise capacity is an indicator of disease prognosis. The aim of the current study was to investigate the association between left heart size and mass with exercise capacity.
Methods: A total of 74 patients were enrolled in the study, with 37 having congestive heart failure (left ventricular ejection fraction (LVEF) < 0.45) and the other 37 with coronary heart disease (by coronary angiography) serving as the control group (LVEF > 0.55). Echocardiography and cardiopulmonary exercise test were performed. The multiply linear regression model was used to evaluate the association between echocardiogrphic indices and exercise capacities.
Results: The study showed that left ventricular end diastolic/systolic diameter (LVEDD/LVESD), left atrial diameter (LAD) and left ventricular mass index (LVMI) were significantly enlarged in patients with chronic heart failure compared with controls (P < 0.01). The VO(2)AT, Peak VO(2), Load AT, and Load Peak in chronic heart failure patients were also significantly reduced compared with controls (P < 0.05), VE/VCO(2) slope was increased in patients with chronic heart failure (P < 0.01). Multivariate linear regression analysis indicated that the patients' exercise capacity was significantly associated with the left heart size and mass, however, the direction and/or strength of the associations sometimes varied in chronic heart failure patients and controls. Load AT correlated negatively with LVEDD in chronic heart failure patients (P = 0.012), while Load AT correlated positively with LVEDD in control patients (P = 0.006). VE/VCO(2) slope correlated positively with LAD (B = 0.477, P < 0.0001) in chronic heart failure patients, while the VE/VCO(2) slope correlated negatively with LAD in control patients (P = 0.009).
Conclusion: The study indicates that the size of LVEDD and LAD are important determinants of exercise capacity in patients with CHF, which may be helpful to identify exercise tolerance for routine monitoring of systolic heart failure.