Effects of inspiratory muscle training in patients with heart failure with preserved ejection fraction

Inspiratory Muscle Training and Functional Electrical Stimulation for Treatment of Heart Failure With Preserved Ejection Fraction: Rationale and Study Design of a Prospective Randomized Controlled Trial

Heart failure with preserved ejection fraction (HFpEF) has become the most prevalent form of heart failure in developed countries. Regrettably, there is no evidence-based effective therapy for HFpEF. We seek to evaluate whether inspiratory muscle training, functional electrical stimulation, or a combination of both can improve exercise capacity as well as left ventricular diastolic function, biomarker profile, quality of life (QoL), and prognosis in patients with HFpEF. A total of 60 stable symptomatic patients with HFpEF (New York Heart Association class II-III/IV) will be randomized (1:1:1:1) to receive a 12-week program of inspiratory muscle training, functional electrical stimulation, a combination of both, or standard care alone. The primary endpoint of the study is change in peak exercise oxygen uptake; secondary endpoints are changes in QoL, echocardiogram parameters, and prognostic biomarkers. As of March 21, 2016, thirty patients have been enrolled. Searching for novel therapies that improve QoL and autonomy in the elderly with HFpEF has become a health care priority. We believe that this study will add important knowledge about the potential utility of 2 simple and feasible physical interventions for the treatment of advanced HFpEF.

Inspiratory Muscle Weakness is Associated With Exercise Intolerance in Patients With Heart Failure With Preserved Ejection Fraction: A Preliminary Study

BACKGROUND

The relationship between inspiratory muscle weakness (IMW) and exercise intolerance in patients with heart failure with preserved ejection fraction (HFpEF) remains unestablished.

METHODS AND RESULTS

The present study enrolled 40 patients with HFpEF (EF ≥45%). IMW was defined as maximum inspiratory pressure <70% normal predicted values. The function of the diaphragm was assessed by means of ultrasound measurement of muscle thickening of the diaphragm. IMW was prevalent in 27.5% of patients. Patients with IMW had significantly lower vital capacity relative to normal predicted values (%VC), lower knee extensor muscle strength in relation to body weight (%KEMS), poorer nutritional status as assessed by means of the Geriatric Nutritional Risk Index, and shorter 6-minute walk distance (6MWD) compared with patients without IMW (all P < .05). Impaired diaphragm muscle thickening at end-inspiration (median value < 3.9 mm) was significantly associated with a high prevalence of IMW and reduced 6MWD (all P < .05). Subgroup analysis showed that IMW was accompanied by a further decrease in 6MWD in patients with restrictive pulmonary dysfunction (%VC <80%) or lower-limb muscle weakness (median %KEMS <30%; all P < .05).

CONCLUSIONS

IMW is associated with exercise intolerance in patients with HFpEF.

Heart Failure as a Newly Approved Diagnosis for Cardiac Rehabilitation: Challenges and Opportunities

Many see the broadened eligibility of cardiac rehabilitation (CR) to include heart failure with reduced ejection fraction (HFrEF) as a likely catalyst to high CR enrollment and improved care. However, such expectation contrasts with the reality that CR enrollment of eligible coronary heart disease patients has remained low for decades. In this review, entrenched obstacles impeding utilization of CR are considered, particularly in relation to potential HFrEF management. The strengths and limitations of the HF-ACTION (Heart Failure-A Controlled Trial Investigating Outcomes of Exercise Training) trial to advance precepts of CR are considered, as well as gaps that this trial failed to address, such as the utility of CR for patients with heart failure with preserved ejection fraction and the conundrum of poor patient adherence.

Clinical outcomes and cardiovascular responses to exercise training in heart failure patients with preserved ejection fraction: a systematic review and meta-analysis

Exercise training induces physical adaptations for heart failure patients with systolic dysfunction, but less is known about those patients with preserved ejection fraction. To establish whether exercise training produces changes in peak V̇o2 and related measures, quality of life, general health, and diastolic function in heart failure patients with preserved ejection fraction. We conducted a MEDLINE search (1985 to October 10, 2014), for exercise-based rehabilitation trials in heart failure, using search terms "exercise training, heart failure with preserved ejection fraction, heart failure with normal ejection fraction, peak V̇o₂, and diastolic heart dysfunction". Seven intervention studies were included providing a total of 144 exercising subjects and 114 control subjects, a total of 258 participants. Peak V̇o₂ increased by a mean difference (MD) 2.13 ml·kg(-1)·min(-1) [95% confidence interval (CI) 1.54 to 2.71, P < 0.00001] in exercise training vs. sedentary control, equating to a 17% improvement from baseline. The corresponding data are provided for the following exercise test variables: V̇e/V̇co₂ slope, MD 0.85 ml·kg(-1)·min(-1) (95% CI 0.05 to 1.65, P = 0.04); maximum heart rate, MD 5.60 beats per minute (95% CI 3.95 to 7.25, P < 0.00001); Six-Minute Walk Test, MD 32.1 m (95% CI 17.2 to 47.1, P < 0.0001); and indices of diastolic function: E/A ratio, MD 0.07 (95% CI 0.02 to 0.12, P = 0.005); E/E' ratio MD -2.31 (95% CI -3.44 to -1.19, P < 0.0001); deceleration time (DT), MD -13.2 ms (95% CI -19.8 to -6.5, P = 0.0001); and quality of life: Minnesota Living with Heart Failure Questionnaire, MD -6.50 (95% CI -9.47 to -3.53, P < 0.0001); and short form-36 health survey (physical dimension), MD 15.6 (95% CI 7.4 to 23.8, P = 0.0002). In 3,744 h patient-hours of training, not one death was directly attributable to exercise. Exercise training appears to effect several health-related improvements in people with heart failure and preserved ejection fraction.