In patients with heart failure who have a pacemaker, inspiratory muscle strength training (IST) and endurance training of the inspiratory muscle (IET) show equal benefit with respect to respiratory muscle endurance, lung function, quality of life, dyspnea, fatigue, and physical activity. These findings from a randomized, controlled, double-blind study were published recently in Heart and Lung.

Earlier studies have shown that IST improves the strength of the inspiratory muscles as well as physical endurance in general, but no studies have compared IST with IET in heart failure patients with a pacemaker, noted authors of the current study, who added that implantation of a pacemaker in heart failure patients has been rising dramatically in recent years.

In the current study, Turkish investigators conducted a prospective , randomized, controlled trial (RCT; ClinicalTrials.gov Identifier: NCT03501355) of clinically stable heart failure patients with pacemakers between the ages of 18 and 70 years. Of 110 patients screened, those with conditions such as unstable angina, acute myocardial infarction, or uncontrolled hypertension (74) were excluded. The 36 remaining patients were placed randomly into the IST or the IET cohort and assigned to 8 weeks of inspiratory muscle training, involving high-intensity (50% or more of maximal inspiratory pressure [MIP]), low-repetition training for the strength training group and low-intensity (30% or more of MIP), high-repetition for the endurance training group. 


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Participants trained using a breathing device (POWERbreathe, Classic Low Resistance) designed to create resistance during inhalation. Training proceeded 30 minutes per day, 7 days per week, for 8 weeks. Before and after training, all participants underwent 6-minute walk tests (6MWT); pulmonary function, peripheral muscle strength, dyspnea, and fatigue perception measurements; incremental shuttle walk tests (ISWT); and measurements of respiratory muscle strength and endurance, quality of life, and physical activity level measurements. 

Both groups achieved significant improvements in MIP, maximal expiratory pressure, respiratory muscle endurance, peripheral muscle strength, 6MWT and ISWT walking distances, dyspnea, quality of life, physical activity level, and fatigue scores (P ≤.05), but no significant differences were noted between the groups (P >.05). The training did not produce any significant improvements in percentages of forced expiratory volume in the first second of expiration (FEV1), forced vital capacity (FVC), FEV1/FVC, or forced midexpiratory flow (FEF25%-75%) in or between the cohorts (P >.05). No adverse events occurred during the training.

Limitations of the study included its small sample size and the inclusion of smokers, which could have affected the results.

None of the participants received cardiac rehabilitation before or during the trial, and the adherence of pacemaker patients, especially those with implanted cardiac defibrillators (ICDs), to such programs remains poor because of fear of ICD shocks, according to the authors. But the safety of the training shown in this study should alleviate some of that trepidation. “Considering the current results, inspiratory muscle strength or endurance training should be added as a safe and effective intervention to cardiopulmonary rehabilitation programs for pacemaker patients with HF (heart failure),“ the authors recommended. 

Reference

Katayıfçı N, Boşnak Güçlü M, Şen F. A comparison of the effects of inspiratory muscle strength and endurance training on exercise capacity, respiratory muscle strength and endurance, and quality of life in pacemaker patients with heart failure: a randomized study. Heart Lung. Published online April 23, 2022. doi:10.1016/j.hrtlng.2022.04.006