Ivabradine for Heart Rate Reduction During Exercise in Healthy Adults
ConditionHealthy Adult
Trial statusRecruiting
Trial phaseEarly Phase 1
Trial typeInterventional
Biological sexAll
Age19-79
SponsorUniversity of British Columbia
About this trial
During exercise, working muscles require more oxygen. The heart meets this demand in two ways: by beating faster (heart rate) and by pumping more blood with each beat (stroke volume). Heart rate increases steadily with exercise intensity until exhaustion, but the amount of blood pumped with each beat tends to plateau at moderate intensities. Why the amount of blood pumped with each beat becomes limited before heart rate, however, is not well understood.
Studying these mechanisms is difficult because most drugs that lower heart rate also affect how strongly the heart pumps, making it hard to separate the two effects. One medication that can help with this is ivabradine, which is used to treat people with heart disease who have high resting heart rates. It slows the heart rate without changing how strongly the heart pumps.
This study will investigate whether ivabradine lowers heart rate during exercise in healthy younger and older adults, and whether a higher dose lowers heart rate more. The results will help us better understand how heart rate influences the heart's ability to supply oxygen to the body during exercise, and what limits the ability to exercise as people age.
Participants will:
* Attend three visits at SportsCardiologyBC in Vancouver * Complete a cycling exercise test at each visit to measure heart rate and how hard they can exercise * Take ivabradine (a heart-rate-lowering medication) before the exercise test at Visits 2 and 3 (a lower dose at Visit 2 and a higher dose at Visit 3) * Be monitored for side effects including slow heart rate, visual symptoms, and headache.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Healthy males and females aged 19-39 years, and 60-79 years
Engaging in regular aerobic exercise (e.g., running, cycling, swimming, hiking, field, ice, or racquet sports) at least once per week
Disqualifiers
History of any cardiovascular condition, including hypertension
Use of any chronic medication
History of any respiratory condition, including asthma
Smoking, including cannabis or vaping in the past year
Trial design
Design model
Single group
Treatments tested in this trial
Ivabradine (single oral dose)
DrugA single oral dose of ivabradine is administered at each experimental visit, in a fixed order: 7.5 mg at Visit 2 (one 7.5 mg tablet), and 12.5 mg at Visit 3 (one 7.5 mg + one 5 mg tablet). Ivabradine is a selective hyperpolarization-activated cyclic nucleotide-gated transmembrane (HCN4) channel inhibitor that reduces heart rate without affecting myocardial contractility.
Treatment groups
20 Participants
are divided into 1 treatment groupGroup A: IvabradineExperimental treatment 1 intervention
Trial outcomes
Primary outcomes
1
Heart rate, peak
Highest heart rate achieved during the cardiopulmonary exercise test.
Time frame
Within 30 minutes of exercise onsetSecondary outcomes
1
Heart rate, resting
Average heart rate over the 15 minutes of rest prior to the cardiopulmonary exercise test.
Time frame
Within 15 minutes prior to exercise onset2
Heart rate/work rate
Highest heart rate divided by the highest work rate achieved during the cardiopulmonary exercise test.
Time frame
Within 30 minutes of exercise onset3
Incidence of visual symptoms
Frequency of self-reported visual symptoms (phosphenes) assessed by standardized symptom questionnaire at 15-minute intervals during pre- and post-exercise observation periods.
Time frame
Within 4 hours post-dose administration4
Incidence of headache
Frequency of self-reported headache assessed by standardized symptom questionnaire at 15-minute intervals during pre- and post-exercise observation periods.
Time frame
Within 4 hours post-dose administrationSponsors and contacts
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Source ClinicalTrials.gov