Abstract
Funding Acknowledgements
Type of funding sources: None.
Background
Deterioration of left ventricular function after acute myocardial infarction is common, particular in ST-elevation myocardial infarction (STEMI). This often leads to heart failure with reduced ejection fraction (HFrEF). Exercise training has shown to be beneficial in stable chronic heart failure patients. However, effects of exercise training have been rarely investigated during very early phases of STEMI.
Purpose
The Exercise in Acute Myocardial Infarction (Ex-AMI) pilot study wanted to investigate whether exercise training has beneficial effects on ventricular remodeling under the following conditions:
a) started early after myocardial infarction
b) exclusively after STEMI
c) performed with higher intensity.
The hypothesis of this study was that exercise training early after acute myocardial infarction performed for 24 weeks is superior to usual care, regarding the improvement of echocardiographic parameters. It was also assumed that higher-intensity interval training is more effective than moderate continuous training.
Methods
Therefore, we randomized 19 patients with STEMI (58.0 ± 7.1 years, 5% female) and left ventricular ejection fraction (LVEF) <55% to:
1. Moderate continuous training (MCT; 50-60% VO2peak; n = 6)
2. Higher intensity interval training (HIIT; MCT interspersed by intervals of 80-85% VO2peak; n = 6)
3. Usual care (UC; n = 7)
Exercise groups (EG: MCT and HIIT) started seven days after STEMI (run-in period for two weeks, followed by a tailored supervised exercise program for 22 weeks). Three-dimensional echocardiography and cardiopulmonary exercise testing were performed at the beginning and at the end of the training period. Patients were also continuously monitored for adverse events.
Results
At baseline, LVEF (46.3 ± 6,5%) as well as exercise capacity (VO2peak: 17.8 ± 4.4·kg-1·min-1) were impaired. In both exercise groups (EG: MCT and HIIT) LVEF improved significantly more than in the control group (mean change +7.3 ± 3.5% in EG vs. 2.3 ± 2.3% in UC; p = 0.007). Furthermore HIIT was not superior to MCT (mean change 7.6 ± 3.6% in HIIT vs. 6.7 ± 4.1% in MCT; p = 0.78) in terms of LVEF. There were no training associated adverse events.
Conclusion
Exercise training early after acute STEMI seems to have anti-remodeling effects. There is a need for more randomized controlled trials to confirm these findings, in order to find the optimal timing and dose of exercise after STEMI.
Abstract Figure. Changes in LVEF (in %) after 24 weeks
Superior Cardiovascular Effect of Aerobic Interval Training Versus Moderate Continuous Training in Heart Failure Patients
