Effects of Slow-paced Breathing on Heart Rate Variability in Patients With Heart Failure

NCT07763353 | Not Yet Recruiting DMC

• 1 other identifier: CS1-26081
• Study Type: interventional
• Target: 27
• Locations: 0 countries
• Sites: N/A

Brief Summary

Background: Heart failure (HF) is a major global public health concern characterized by impaired cardiac function, high mortality, frequent hospital readmissions, and substantial healthcare burden. Autonomic nervous system (ANS) dysfunction plays a critical role in the pathophysiology of HF, typically presenting as increased sympathetic activity and reduced parasympathetic activity. Heart rate variability (HRV), a non-invasive marker of cardiac autonomic regulation, has been widely used to evaluate autonomic function and predict clinical outcomes in patients with HF. Reduced HRV is associated with increased risks of sudden cardiac death, cardiovascular events, and hospital readmission. Although cardiac rehabilitation (CR) has been demonstrated to improve exercise capacity, quality of life, and clinical outcomes in HF patients, its effects on autonomic modulation, particularly during Phase I cardiac rehabilitation, remain insufficiently investigated. Slow-paced breathing (SPB) has emerged as a potential non-pharmacological intervention for enhancing autonomic regulation. By synchronizing respiratory rhythm with cardiovascular oscillations, SPB may enhance baroreflex sensitivity, increase vagal activity, and improve HRV. Previous studies have suggested beneficial effects of SPB on autonomic function; however, the findings remain inconsistent, and evidence regarding its short-term effects on HRV among hospitalized HF patients undergoing early cardiac rehabilitation is limited. Therefore, further investigation is warranted to determine whether SPB can provide additional autonomic benefits when incorporated into Phase I cardiac rehabilitation. Objective: This study aims to investigate the effects of slow-paced breathing combined with Phase I cardiac rehabilitation on autonomic nervous system function in patients with heart failure, using HRV as the primary outcome measure. Methods: This study will employ a parallel randomized controlled trial design. Hospitalized patients diagnosed with heart failure will be randomly allocated into either the SPB intervention group or the control group. Both groups will receive standard Phase I cardiac rehabilitation, while the intervention group will additionally receive slow-paced breathing training. The primary outcomes will include changes in HRV parameters, including time-domain indices (standard deviation of NN intervals \[SDNN\] and root mean square of successive differences \[RMSSD\]) and frequency-domain indices (low-frequency power \[LF\], high-frequency power \[HF\], and LF/HF ratio), to evaluate changes in cardiac autonomic regulation before and after intervention.

Conditions

Heart Failure

Keywords

Heart Failure; rehabilitation; HRV

Outcome Measures

Primary Outcomes (1)

• Heart Rate Variability

  20 mins/session, 2 sessions/day, for 8 weeks

Study Arms (2)

Slow-paced breathing

EXPERIMENTAL

Other: Slow-paced breathing intervention

Usual Breathing

PLACEBO COMPARATOR

Other: Placebo

Interventions

Slow-paced breathing intervention OTHER

Subjects will undergo slow breathing training, guided by researchers or an app, to reduce their breathing rate to 4-7 breaths per minute. The training will consist of 20-minute sessions, practiced twice daily, for a total duration of 8 weeks.

Slow-paced breathing

Placebo OTHER

Participants randomly assigned to this arm will maintain their natural breathing patterns or receive usual breathing care without any slow-paced breathing intervention. This arm serves as a baseline comparison for cardiovascular control and heart rate variability (HRV) outcomes.

Usual Breathing

Eligibility Criteria

• Age: 20 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients diagnosed with heart failure during hospitalization and who are clinically stable.

You may not qualify if:

• Respiratory distress at rest with the utilization of accessory neck muscles (neck breathing pattern).
• Presence of an implanted cardiac pacemaker. Chronic pulmonary diseases, such as chronic obstructive pulmonary disease (COPD), pulmonary hypertension, pulmonary fibrosis, or exercise-induced asthma.
• Current use of mechanical ventilation. Severe aortic stenosis. Aortic dissection. Acute myocarditis, pericarditis, or infective endocarditis. Inability to walk independently due to orthopedic, neurological, or other medical conditions.
• Inability to understand the study protocols or cooperate, such as individuals with psychiatric disorders, dementia, or a history of stroke.

Sponsors & Collaborators

• Chung Shan Medical University: lead

MeSH Terms

Conditions

Heart Failure

Condition Hierarchy (Ancestors)

Heart Diseases; Cardiovascular Diseases

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Study Record Dates

• First Submitted: August 10, 2026
• First Posted: August 13, 2026
• Study Start (Estimated): August 15, 2026
• Primary Completion (Estimated): August 14, 2027
• Study Completion (Estimated): August 14, 2027
• Last Updated: August 13, 2026

Record last verified: 2026-08