Long-term effects of device-guided slow breathing in stable heart failure patients with reduced ejection fraction

Clinical Research in Cardiology https://doi.org/10.1007/s00392-018-1310-7 ORIGINAL PAPER Long-term effects of device-guided slow breathing in stable heart failure patients with reduced ejection fraction Kamila Lachowska1 · Jerzy Bellwon1 · Krzysztof Narkiewicz2 · Marcin Gruchała1 · Dagmara Hering1,2 Received: 16 April 2018 / Accepted: 19 June 2018 © The Author(s) 2018 Abstract Background Slow breathing (SLOWB) alleviates symptoms of chronic heart failure (HF) but its long-term effects are unknown. We examined the acute and long-term impact of device-guided breathing on hemodynamics and prognostic parameters in HF patients with reduced ejection fraction (HFrEF). Methods and results Twenty-one patients with HFrEF (23.9 ± 5.8%, SD ± mean) on optimal medical therapy underwent blood pressure (BP), heart rate (HR), HR variability, 6-min walk test (6MWT), cardiopulmonary exercise testing (CPET), and echocardiography measurements before and 3 months after SLOWB home training (30 min daily). After 3 months, all patients were assigned to continue SLOWB (Group 1) or no-SLOWB (Group 2). All tests were repeated after 6 months. Acute SLOWB (18 ± 5 vs 8 ± 2 breaths/min, P < 0.001) had no influence on BP and HR but improved saturation (97 ± 2 vs 98 ± 2%, P = 0.01). Long-term SLOWB reduced office systolic BP (P < 0.001) but not central or ambulatory systolic BP. SLOWB reduced SDNN/RMSSD ratio (P < 0.05) after 3 months. One-way repeated measures of ANOVA revealed a significant increase in 6MWT and peak RER (respiratory exchange ratio) from baseline to 6-month follow-up in group 1 (P < 0.05) but not group 2 (P = 0.85 for 6MWT, P = 0.69 for RER). No significant changes in echocardiography were noted at follow-up. No HF worsening, rehospitalisation or death occurred in group 1 out to 6-month follow-up. Two hospitalizations for HF decompensation and two deaths ensued in group 2 between 3- and 6-month follow-up. Conclusions SLOWB training improves cardiorespiratory capacity and appears to slow the progression of HFrEF. Further long-term outcome studies are required to confirm the benefits of paced breathing in HFrEF. Keywords Heart failure with reduced ejection fraction · Slow breathing · Hemodynamics · 6-Min walk test · Functional capacity · Heart rate variability Introduction Chronic heart failure (HF) remains a challenging problem with a considerable impact on the global burden of cardiovascular (CV) morbidity and mortality [1–3]. Despite advances in HF prevention and management, the worldwide prevalence of newly diagnosed patients with HF is expected to rise further, accounting for a 46% increase in prevalence from 2012 to 2030 [4–9]. This is driven by prolonged life expectancy, improvements in therapies for coronary artery * Dagmara Hering 1 1st Department of Cardiology, Medical University of Gdansk, Gdańsk, Poland 2 Department of Hypertension and Diabetology, Medical University of Gdansk, Debinki 7c, 80‑952 Gdańsk, Poland disease (CAD) and sudden cardiac death, and the growing incidence of co-morbidities (i.e. hypertension, diabetes) contributing to the development of HF [10–16]. Differentiation of patients with HF is critical due to diverse underlying aetiologies, associated co-morbidities and responses to treatment [17–23]. Pharmacological therapies have improved survival and reduced hospital admission in HF [24–27]. However, hypotension and resulting tachycardia often prevent further drug initiation and up-titration. Along with pharmacological approaches, surgical implantable electrical devices for the treatment of HF patients with reduced ejection fraction (HFrEF) improve symptoms, reduce the risk of death and all-cause mortality in primary and secondary prevention [10, 28–30]. Nevertheless, in HFrEF patient outcomes remain unsatisfactory high with an increased risk for sudden death, worsening HF, frequent hospitalization for CV events and recurrent decompensation [31–33]. Given that 13 Vol.:(0123456789) Clinical Research in Cardiology currently available optimal medical drug and device therapies are insufficient to halt disease progression, an unmet need for other therapeutic approaches clearly exists [34–38]. Amongst behavioural interventions, slowing spontaneous breathing rate below 10 breaths/min has the potential to favourably affect CV regulation [39–42]. The use of slow breathing (SLOWB) technique has been shown to reduce dyspnoea, improve oxygen saturation and exercise tolerance in HF patients, acutely increase baroreflex gain and stability in patients with CV disease and a risk for sudden death [42–45]. Data from pilot studies of patients with systolic chronic HF have demonstrated the feasibility of device-guided SLOWB pacing with the use of the RESPeRATE, improvements in NYHA class and left ventricle ejection fraction (LVEF), reductions in pulmonary pressure [46, 47] and breathlessness [48]. The effects of SLOWB training on blood pressure (BP) in chronic HF has been reported to be marginal with low incidence of orthostatic hypotension [49]. A recent study has demonstrated an improvement of physical capacity and systolic heart function with a tendency to attenuate sleep disturbances in chronic HF [50]. Although the currently available results with paced breathing are promising in chronic HF and the mechanistic rationale for the use of SLOWB is apparent, not all HF patients seemed to respond to this behavioural technique [48]. Previous studies in HF were limited to acute effects of SLOWB or 10–12 weeks in duration. The long-term impact of regular SLOWB performance on prognostic factors in chronic HF has not yet been investigated. Therefore, this study sought to comprehensively explore the effects of home-paced Fig. 1  Patient flow diagram. Study patient recruitment flow chart based on CONSORT guidelines 13 breathing on clinical, hemodynamic and prognostic parameters in stable patients with severe HFrEF, all of whom received optimal medical drug and device-based therapies. Methods Subjects This prospective unblinded case-series study was approved by the Institutional Ethics Committee and written informed consent was obtained from all patients. Eligible participants were adults aged 18 or over who met the eligibility criteria for HFrEF diagnosis and managements as per European Society of Cardiology (ESC) guidelines [10, 51]. Only stable patients with chronic HFrEF who were receiving optimal medical pharmacological (i.e. maximum tolerated dose of all recommended drug classes) and surgical implementable device therapies were recruited into the study. The inclusion criteria required stable unchanged medication (without a need to increase a dose of furosemide) for at least 6 weeks prior to study enrolment. Exclusion criteria were acute coronary syndrome (ACS) ≤ 3 months, percutaneous coronary angioplasty ≤ 3 months, coronary artery bypass graft ≤ 3 months, acute cerebrovascular disease ≤ 3 months, chronic obstructive pulmonary disease, asthma, upper pulmonary tr (...truncated)