Exercise capacity, breathing pattern, and gas exchange during exercise for patients with isolated diastolic dysfunction

Background: Left ventricular diastolic dysfunction (Dial)) is as common as left ventricular systolic dysfunction. Whether these causes of heart failure lead to similar breathing pattern and gas exchange responses to exercise remains unclear. Methods: Participants (control subjects [n = 471, systolic dysfunction [n = 461, and Dial) [n = 40]) underwent resting echocardiograms; and cardiopulmonary exercise testing. Results: Patients demonstrated lower peak oxygen consumption and tidal volume than control subjects (P <.05). Ventilation tended to be highest in Dial). The submaximal ventilatory equivalent for carbon dioxide was highest in Dial). Left atrial volume (all groups) was correlated with peak oxygen consumption (r = -0.38) whereas the ratio of early mitral inflow velocity to early mitral annular velocity was related to peak oxygen consumption (r = -0-36) and treadmill time (r = -0-35). Conclusion: Isolated Dial) is associated with altered breathing pattern and gas exchange similar to systolic dysfunction. Elevated left atrial volume, higher early mitral inflow velocity to early mitral annular velocity ratio, or both are predictive of exercise capacity and elevated ventilatory responses in patients with Dial) suggesting a role for dysfunctional ventricular relaxation.