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Background In chronic heart failure (CHF), impaired pulmonary function can independently contribute to oxygen desaturation and reduced physical activity. We investigated the effect of breathing rate on oxygen saturation and other respiratory indices.
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.
Background—It is well established that a depressed baroreflex sensitivity may adversely influence the prognosis in patients with chronic heart failure (CHF) and in those with previous myocardial infarction.Methods and Results—We tested whether a slow breathing rate (6 breaths/min) could modify the baroreflex sensitivity in 81 patients with stable (2 weeks) CHF (age, 58Ϯ1 years; NYHA classes I [6 patients], II [33], III [27], and IV [15]) and in 21 controls. Slow breathing induced highly significant increases in baroreflex sensitivity, both in controls (from 9.4Ϯ0.7 to 13.8Ϯ1.0 ms/mm Hg, PϽ0.0025) and in CHF patients (from 5.0Ϯ0.3 to 6.1Ϯ0.5 ms/mm Hg, PϽ0.0025), which correlated with the value obtained during spontaneous breathing (rϭϩ0.202, Pϭ0.047). In addition, systolic and diastolic blood pressure decreased in CHF patients (systolic, from 117Ϯ3 to 110Ϯ4 mm Hg, Pϭ0.009; diastolic, from 62Ϯ1 to 59Ϯ1 mm Hg, Pϭ0.02).
Conclusions—These data suggest that in patients with CHF, slow breathing, in addition to improving oxygen saturation and exercise tolerance as has been previously shown, may be beneficial by increasing baroreflex sensitivity. (Circulation. 2002;105:143-145.)