Effect of Ivabradine use on exercise capacity in patients with transposition of the great arteries (TGA) post atrial switch repair

Status

Completed

Phases

Phase 2

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12621000196842

Acronym

IVAMUS

Enrollment

Registered

2021-02-24

Start date

2021-05-03

Completion date

2025-07-02

Last updated

2026-08-24

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

This is a single centre, randomized, double blind, cross over study designed to assess the effect of Ivabradine (as a heart rate lowering drug) on the exercise capacity of adults with transposition of the great arteries who have had a previous atrial switch repair. Subjects will be randomised to Ivabradine or placebo after undergoing a baseline cardiopulmonary stress test. Repeat testing will be performed after 4 weeks of treatment then at 8 weeks after a crossover at 4 weeks. We hypothesise that heart rate lowering on exercise with improve exercise capacity (VO2 max) in these adults owing to improved blood flow through the heart (ie. improved atrio-ventricular transport).

Interventions

Ivabradine Dose: 5mg twice a day for first two weeks, then 5mg twice a day or 7.5mg twice a day for second two weeks according to heart rate check at two weeks. Duration: 4 weeks Mode of administration: oral tablet, overencapsulated Adherence: RMH pharmacy will perform a pill count at two week and four week visits Crossover occurs at 4 weeks with no washout required.

Study design

Allocation

Randomised controlled trial

Intervention model

Crossover

Primary purpose

Treatment

Masking

Blinded (masking used) (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender

All

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

Age > 18 Transposition of great arteries with previous atrial switch repair

Exclusion criteria

1. Congestive heart failure 2. Unable to exercise 3. Not in sinus rhythm (atrial flutter/fibrillation) 4. Bradycardia or resting heart rate below 60bpm 5. Severe hepatic impairment 6. Combination with strong cytochrome P450 inhibitors (eg. Ketoconazole, macrolide antibiotics, HIV protease inhibitors, nefazodone) or with QT prolonging medications 7. Pregnancy, lactation 8. Rare hereditary problems of galactose intolerance, Lapp lactase deficiency, glucose-galactose malabsorption (lactose excipient in tablet)

Outcome results