Exercise stress testing using a ramp protocol has been favored for cardiopulmonary exercise testing (CPX) in patients with heart failure (HF). However, the stepwise protocol for CPX was preferred for its possible combination with exercise stress echocardiography (ESE). We therefore, investigated the feasibility and safety of using a stepwise protocol for CPX-ESE in patients with HF.
Ambulatory outpatients with chronic HF were enrolled for a symptom-limited stepwise bicycle exercise test in the semi-supine position on a cycle ergometer. The test was started at a workload of 30W and increased by 15W every 3 minutes until maximal exertion. The echocardiographic and respiratory variables and any complications during the exercise, were recorded.
Among a total of 36 participants (age 61.2 ± 12.4 years, 69.4% men), all subjects achieved AT during CPX-ESE and reached 72.3% of the age-predicted peak heart rate. The peak VO2 was 14.7 ml/kg/min, and the peak RER was 1.25. There were no severe adverse complications, and only 2 minor rhythmic events were reported: non-sustained supraventricular tachycardia and isolated ventricular premature beats. The echocardiographic images acquired at each stage were of good quality in 92.6% of all acquisitions and the intra-observer and interobserver repeatability was >80%.
The stepwise protocol, with an initial workload of 30W, followed by 15W increments every 3 minutes, was feasible and provided an adequate stress load for patients with HF. This exercise stress modality was safe and well-tolerated.