# Effect of High-Intensity Interval Training in Patients With Atrial Fibrillation: A Randomized Clinical Trial

PMID: 36315143
Journal: JAMA network open
Published: 2022 Oct 3
Authors: Reed JL, Terada T, Vidal-Almela S, Tulloch HE, Mistura M, Birnie DH, Wells GA, Nair GM, Hans H, Way KL, Chirico D, O'Neill CD, Pipe AL

## Question

Does 12 weeks of HIIT improve functional capacity and quality of life more than moderate-to-vigorous cardiovascular rehabilitation in patients with persistent or permanent atrial fibrillation?

## Summary

In adults with persistent or permanent atrial fibrillation, a supervised twice-weekly 23-minute cycling HIIT program produced similar 12-week improvements to a 60-minute cardiovascular rehabilitation program in walking distance, quality of life, resting heart rate, and physical activity. HIIT used much less conditioning time but had more dropouts and a small number of exercise-related adverse events.

## Population

- Adults with persistent or permanent atrial fibrillation in a cardiac rehabilitation center
- Sample size: 86
- Age: Mean 69 years
- Sex: 66.3% men
- Fitness level: Low cardiorespiratory fitness; not routinely exercising more than twice weekly
- Health status: Stable, rate-controlled persistent or permanent atrial fibrillation

## Methodology

- Single-center parallel-group randomized clinical trial
- 12 weeks
- Controlled study design.

## Protocol

- HIIT.
- Modality: Upright cycle ergometer.
- Work intervals: 30 s at 80%-100% peak power output.
- Recovery: 30 s active recovery; 4 min between two blocks.
- Sets or repetitions: Two 8-min blocks, 16 work intervals.
- Intensity: 80%-100% PPO after progression, with possible increases up to 150% PPO.
- Session duration: 23 min.
- Frequency: 2 sessions/week.
- Program length: 12 weeks.
- Progression: Started at 50% PPO and increased by 10% after every other session.
- Cardiovascular rehabilitation.
- Modality: Walking/jogging, cycling, elliptical, or rowing plus strengthening/stretching.
- Work intervals: 30 min continuous aerobic conditioning.
- Recovery: Not interval-based.
- Sets or repetitions: Continuous conditioning.
- Intensity: 67%-95% peak heart rate and RPE 12-16.
- Session duration: 60 min.
- Frequency: 2 sessions/week.
- Program length: 12 weeks.

## Outcomes

### 6MWT
Status: no clear change
Both groups improved, with no significant between-group difference.

### Quality of life
Status: no clear change
General and disease-specific quality-of-life changes did not differ significantly between groups.

### Physical activity
Status: unclear
Moderate-to-vigorous physical activity changes were similar.

### Safety
Status: unclear
Exercise-related adverse events were uncommon, but HIIT had more dropouts.

## Practical Insights

- For stable AF patients in a supervised clinical setting, 30-second cycling intervals can reduce time burden while preserving rehabilitation benefits.
- HIIT equivalence should be paired with careful screening, monitoring, and symptom reporting.
- Clinical HIIT protocols are not automatically transferable to unsupervised consumer workouts.

## Limitations

- Single-center trial
- More dropouts in the HIIT group
- No long-term follow-up beyond post-intervention testing
- Findings apply to medically screened stable AF patients

## Safety And Adherence

- 2 exercise-related adverse events occurred during 749 HIIT sessions.
- One listed exercise-related event included knee swelling/medial collateral ligament tear.
- HIIT had significantly more dropouts than CR.
- Participants were medically screened and trained under supervision.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/36315143/) (pubmed)
- [DOI](https://doi.org/10.1001/jamanetworkopen.2022.39380) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9623436/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.