Heart FailureNCT07763353
Effects of Slow-paced Breathing on Heart Rate Variability in Patients With Heart Failure
A study testing Slow-paced breathing intervention in people with Heart Failure, run by Chung Shan Medical University.
Trial 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. Read more about this study
- Who is it for?
- Ages 20 to 80 years
- Conditions the study is for
- Heart Failure
- What is being tested?
- Slow-paced breathing intervention
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 27 participants
- Where
- No sites listed yet
- Study dates
- 15 Aug 2026to 14 Aug 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients diagnosed with heart failure during hospitalization and who are clinically stable.
Who cannot join
- 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.
About this study
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.
Read more
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.
Read the detailed description
Physiological Link Between Slow-Paced Breathing and Autonomic Nervous System Regulation
Although conventional breathing exercises (e.g., diaphragmatic breathing and deep breathing) facilitate lung expansion, prevent premature alveolar and airway collapse, and maintain normal respiratory function and adequate gas exchange, these techniques primarily focus on the quantity of breathing and respiratory muscle activity. In contrast, slow-paced breathing (SPB) is a controlled breathing technique that primarily regulates the breathing frequency and maintains a fixed inspiratory-to-expiratory ratio, allowing synchronization with intrinsic cardiovascular oscillations to enhance cardiopulmonary function and autonomic regulation. Slow-paced breathing, also referred to as slow breathing, resonance frequency breathing, or paced breathing, is considered a method that influences autonomic nervous system (ANS) function through modulation of respiratory frequency.
The interaction between respiration and cardiovascular regulation is mediated through the autonomic nervous system, which regulates heart rate, blood pressure, and respiratory patterns. This physiological coupling is known as respiratory sinus arrhythmia (RSA), which is considered one of the primary contributors to HRV. Under normal RSA conditions, heart rate slightly increases during inspiration and decreases during expiration. This phenomenon reflects parasympathetic modulation of cardiac activity and serves as an important physiological indicator of vagal function.
The interaction between respiratory and cardiovascular systems involves three major components: the respiratory network, the cardiovascular network, and their central synaptic interactions. The respiratory network within the central nervous system generates respiratory commands that activate respiratory motor neurons, leading to respiratory muscle activity. During this process, two major types of afferent feedback signals are generated from the lungs: chemical feedback and mechanical feedback. Chemical feedback is mediated through the aortic arch and carotid bodies, which detect changes in oxygen, carbon dioxide, and hydrogen ion concentrations and transmit these signals back to the brain. Mechanical feedback occurs through lung expansion during inspiration, which activates lung stretch receptors; meanwhile, respiratory-induced changes in intrathoracic pressure also generate afferent signals transmitted to the central nervous system.
Meanwhile, the cardiovascular network regulates cardiac activity and vascular smooth muscle function through the autonomic nervous system, resulting in changes in heart rate and vascular resistance. The vascular system determines systolic arterial pressure (SAP) and diastolic arterial pressure (DAP), leading to alterations in blood pressure and arterial blood conditions. Changes in blood pressure stimulate baroreceptors located in the aortic arch and carotid sinus, which subsequently transmit sensory information back to the brain. Ultimately, these signals are integrated within the nucleus tractus solitarius (NTS) in the brainstem, resulting in respiratory-mediated modulation of cardiovascular autonomic control
- Conditions
- Heart Failure
- Being tested
- Slow-paced breathing intervention, Placebo
- Keywords
- Heart Failure, rehabilitation, HRV
- Medical subject headings
- Heart Failure
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Slow-paced breathing interventionOther
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.
PlaceboOther
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.
| Study group | Role | What they receive |
|---|---|---|
| Slow-paced breathing | Experimental | Not described Receives: Other: Slow-paced breathing intervention |
| Usual Breathing | Placebo comparator | Not described Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Heart Rate Variability
Measured: 20 mins/session, 2 sessions/day, for 8 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Aug 2026
- Study start15 Aug 2026 (estimated)
- Primary completion14 Aug 2027 (estimated)
- Study completion14 Aug 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Heart FailureStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 27 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Chung Shan Medical University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Chung Shan Medical University Hospital, Chung Shan Medical University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07763353
- Sponsor's protocol ID
- CS1-26081
- Status last verified
- Aug 2026
- First submitted
- 10 Aug 2026
- Last updated
- 13 Aug 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 13 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Slow-paced Breathing on Heart Rate Variability in Patients With Heart Failure
- ClinicalTrials.gov ID
- NCT07763353
- Acronym / sponsor ID
- CS1-26081
- Conditions
- Heart Failure
- Keywords
- Heart Failure, rehabilitation, HRV
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 27 participants (estimated)
- Lead sponsor
- Chung Shan Medical UniversityUniversity, hospital or other
- Study start
- 15 Aug 2026 (estimated)
- Primary completion
- 14 Aug 2027 (estimated)
- Study completion
- 14 Aug 2027 (estimated)
- First posted
- 13 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
Physiological Link Between Slow-Paced Breathing and Autonomic Nervous System Regulation
Although conventional breathing exercises (e.g., diaphragmatic breathing and deep breathing) facilitate lung expansion, prevent premature alveolar and airway collapse, and maintain normal respiratory function and adequate gas exchange, these techniques primarily focus on the quantity of breathing and respiratory muscle activity. In contrast, slow-paced breathing (SPB) is a controlled breathing technique that primarily regulates the breathing frequency and maintains a fixed inspiratory-to-expiratory ratio, allowing synchronization with intrinsic cardiovascular oscillations to enhance cardiopulmonary function and autonomic regulation. Slow-paced breathing, also referred to as slow breathing, resonance frequency breathing, or paced breathing, is considered a method that influences autonomic nervous system (ANS) function through modulation of respiratory frequency.
The interaction between respiration and cardiovascular regulation is mediated through the autonomic nervous system, which regulates heart rate, blood pressure, and respiratory patterns. This physiological coupling is known as respiratory sinus arrhythmia (RSA), which is considered one of the primary contributors to HRV. Under normal RSA conditions, heart rate slightly increases during inspiration and decreases during expiration. This phenomenon reflects parasympathetic modulation of cardiac activity and serves as an important physiological indicator of vagal function.
The interaction between respiratory and cardiovascular systems involves three major components: the respiratory network, the cardiovascular network, and their central synaptic interactions. The respiratory network within the central nervous system generates respiratory commands that activate respiratory motor neurons, leading to respiratory muscle activity. During this process, two major types of afferent feedback signals are generated from the lungs: chemical feedback and mechanical feedback. Chemical feedback is mediated through the aortic arch and carotid bodies, which detect changes in oxygen, carbon dioxide, and hydrogen ion concentrations and transmit these signals back to the brain. Mechanical feedback occurs through lung expansion during inspiration, which activates lung stretch receptors; meanwhile, respiratory-induced changes in intrathoracic pressure also generate afferent signals transmitted to the central nervous system.
Meanwhile, the cardiovascular network regulates cardiac activity and vascular smooth muscle function through the autonomic nervous system, resulting in changes in heart rate and vascular resistance. The vascular system determines systolic arterial pressure (SAP) and diastolic arterial pressure (DAP), leading to alterations in blood pressure and arterial blood conditions. Changes in blood pressure stimulate baroreceptors located in the aortic arch and carotid sinus, which subsequently transmit sensory information back to the brain. Ultimately, these signals are integrated within the nucleus tractus solitarius (NTS) in the brainstem, resulting in respiratory-mediated modulation of cardiovascular autonomic control
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Slow-paced breathing | Experimental | Other: Slow-paced breathing intervention |
| Usual Breathing | Placebo comparator | Other: Placebo |
Who may qualify
- Ages
- 20 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Patients diagnosed with heart failure during hospitalization and who are clinically stable.
Key exclusion criteria (4 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Slow-paced breathing interventionSubjects 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. | Other | Slow-paced breathing |
| PlaceboParticipants 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. | Other | Usual Breathing |
Primary outcome
Heart Rate Variability
Time frame: 20 mins/session, 2 sessions/day, for 8 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Aug 2026.
Related trials for Heart Failure
RecruitingPhase 4
The Effects of Ferric Derisomaltose in Patients With Acute Heart Failure and Iron Deficiency on Exercise Capacity and Quality of Life(COREVIVE-HFrEF)
Heart Failure With Reduced Ejection Fraction, Iron Deficiency
Not yet recruitingPhase 2
A Study of Bimagrumab in Participants With HFpEF
Heart Failure, Diastolic, Diastolic Heart Failure
Recruiting
Evaluation of a French Hospital Discharge Therapeutic Education Program by Nurses for Heart Failure Patient (EduSor)
Heart Failure
Active, not recruiting
Assessment of Combined CCM and ICD Device in HFrEF
Heart Failure, Heart Failure With Reduced Ejection Fraction
Not yet recruiting
RELIEVE-HFrEF TRIAL: REducing Lung congestIon Symptoms Using the v-wavE Shunt in adVancEd Heart Failure With Reduced EF
Heart Failure and Reduced Ejection Fraction, Heart Failure Chronic
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
A study testing Slow-paced breathing intervention in people with Heart Failure, run by Chung Shan Medical University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 13 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Heart Rate Variability (time frame: 20 mins/session, 2 sessions/day, for 8 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Aug 2026.