Cardiopulmonary exercise responses in patients with non-ischemic heart failure and a mildly reduced ejection fraction

Background: The cardiopulmonary response to exercise in patients with heart failure exhibiting a mildly reduced ejection fraction (41%<= EF <= 49%) remains unclear. Materials & methods: A total of 193 consecutive patients with heart failure (excluding those with coronary artery disease) who underwent cardiopulmonary exercise (CPX) tests were examined. CPX variables were compared among patients with reduced, mildly reduced, and preserved EF. Results: The CPX test responses of patients with mildly reduced EF were similar to those of patients with reduced or preserved EF; however, increases in systolic blood pressure during exercise differed significantly (32 +/- 26, 50 +/- 24, and 41 +/- 31 mmHg, respectively; p = 0.016). Grip strength and an increase in systolic blood pressure during exercise were independently associated with peak oxygen uptake in patients with mildly reduced EF (beta = 0.41, 0.35, respectively; p < 0.05). Conclusion: Measurements of grip strength and blood pressure during exercise are useful predictors of prognoses in patients with non-ischemic and mildly reduced EF. Plain language summary: Cardiopulmonary exercise (CPX) test is widely used to evaluate the function related to heart in heart failure patients. The heart failure patients are divided into three groups: with reduced wall motion (HFrEF), with mildly reduced wall motion (HFmrEF) and with preserved wall motion (HFpEF). We compared the cardiopulmonary reaction to exercise among the three groups. The CPX test responses of patients with HFmrEF were similar to those of patients with HFrEF or HFpEF. However, increases in systolic blood pressure during exercise differed (32 +/- 26, 50 +/- 24, and 41 +/- 31 mmHg, respectively; p = 0.016). Grip strength and an increase in systolic blood pressure during exercise were independently associated with peak oxygen uptake, which is an important predictor of rate of death in patients with HFmrEF. Measurements of grip strength and blood pressure during exercise are useful predictors of progress in patients with enough blood supply to the heart and HFmrEF.