Maximal functional capacity in subjects with isolated left bundle branch block: A pilot study.

BACKGROUND: Left bundle branch block (LBBB) has been commonly associated with adverse cardiovascular (CV) events, but the effect of an isolated LBBB on maximal functional capacity is not well characterized. OBJECTIVE: To evaluate maximal functional capacity in adults with isolated LBBB and compare it to healthy population-derived predicted values (adjusted for sex, age, weight, and height). METHODS: This descriptive pilot study included subjects with isolated LBBB derived from outpatient clinics of two academic hospitals. All subjects underwent maximal cardiopulmonary exercise testing (CPET) and a Global Physical Activity Questionnaire (GPAQ). The primary outcome was to evaluate maximal functional capacity according to population-derived predicted values of peak oxygen consumption (peakVO2 ): pp-peakVO2 . The secondary outcome was to report adverse CV events (CV deaths or hospitalizations) at follow-up. RESULTS: A total of 27 (18 women and 9 men) participants were included. The median (interquartile range) age of the sample and time to screening from the first LBBB diagnosis were 62 (51-71) and 3.4 (1.1-8.4) years, respectively. The results of the GPAQ score showed that 19 patients were highly active, and 8 were moderately active. The median of peakVO2 and pp-peakVO2 were 19.3 (15-22.5) ml/kg/min and 88% (79.3%-104.4%), respectively. There were no adverse CV events at a median follow-up after CPET of 3.1 (2.7-3.4) years. CONCLUSION: In this pilot study, adults with isolated LBBB showed reduced maximal functional capacity, despite the absence of cardiac disease and a baseline moderate to highly active lifestyle.

Home-based inspiratory muscle training for management of older patients with heart failure with preserved ejection fraction: does baseline inspiratory muscle pressure matter?

BACKGROUND: Heart failure with preserved ejection fraction is a clinical syndrome characterised by reduced exercise capacity. Some evidence has shown that a simple and home-based programme of inspiratory muscle training offers promising results in terms of aerobic capacity improvement in patients with heart failure with preserved ejection fraction. This study aimed to investigate whether the baseline inspiratory muscle function predicts the changes in aerobic capacity (measured as peak oxygen uptake; peak VO2) after a 12-week home-based programme of inspiratory muscle training in patients with heart failure with preserved ejection fraction. METHODS: A total of 45 stable symptomatic patients with heart failure with preserved ejection fraction and New York Heart Association II-III received a 12-week home-based programme of inspiratory muscle training between June 2015 and December 2016. They underwent cardiopulmonary exercise testing and measurements of maximum inspiratory pressure pre and post-inspiratory muscle training. Maximum inspiratory pressure and peak VO2 were registered in both visits. Multivariate linear regression analysis was used to assess the association between changes in peak VO2 (Δ-peakVO2) and baseline predicted maximum inspiratory pressure (pp-MIP). RESULTS: The median (interquartile range) age was 73 (68-77) years, 47% were women and 35.6% displayed New York Heart Association III. The mean peak VO2 at baseline and Δ-peakVO2 post-training were 10.4±2.8 ml/min/kg and +2.2±1.3 ml/min/kg (+21.3%), respectively. The median (interquartile range) of pp-MIP and Δ-MIP were 71% (64-92) and 39.2 (26.7-80.4) cmH2O, respectively. After a multivariate analysis, baseline pp-MIP was not associated with Δ-peakVO2 (ß coefficient 0.005, 95% confidence interval -0.009-0.019, P=0.452). CONCLUSIONS: In symptomatic and deconditioned older patients with heart failure with preserved ejection fraction, a home-based inspiratory muscle training programme improves aerobic capacity regardless of the baseline maximum inspiratory pressure.