Abstract
BACKGROUND: Previous studies have demonstrated therapeutic benefits of slow breathing (SLOWB) in chronic heart failure (HF) but its impact on cardiovascular reactivity in response to laboratory stressors remains unknown. METHODS: Using device-guided breathing this study explored the acute and long-term effects of SLOWB on hemodynamic responses to handgrip, mental and cold pressor tests, and health-related quality of life (QoL) in stable HF patients with reduced ejection fraction (HFrEF) who had received all available optimal drug and device therapies. Blood pressure (BP) and heart rate (HR) were measured in 21 patients with HFrEF (23.9 ± 5.9%) at rest, during laboratory stressors, before and after acute SLOWB, and 12 weeks after SLOWB home training (30 min daily). Health-related QoL (MacNew questionaries) was assessed before and 12 weeks after SLOWB home training. RESULTS: Resting BP significantly increased in response to three laboratory stressors. Pressor and cardiac changes during mental stress were greater than responses to the handgrip test (p < 0.05). Mental stress also produced a greater HR change than cold pressor test (p < 0.05). Both acute and long-term SLOWB significantly reduced BP and HR responses to mental stress (p < 0.05), but not to isometric and cold pressor tests. SLOWB improved scores of all domains of QoL (p < 0.05) at 12 weeks follow-up. CONCLUSIONS: These findings demonstrate that SLOWB reduces acute and chronic effects of cardiovascular reactivity to mental stress and improves various aspects of health-related QoL in patients with severe HFrEF. Whether stress reduction and psychological changes achieved with SLOWB may translate to improved outcomes in HFrEF warrants further exploration.