Modest Amounts of Physical Activity Are Associated with Reduced Atrial and Ventricular Arrhythmias
The following is copied from Practice Updates and available at:
Elliott and colleagues (European Heart Journal 2020) used data from 402,406 participants in the UK Biobank cohort to examine the relationship between physical activity (PA) and the incidence of atrial fibrillation (afib), ventricular arrhythmias, and brady-arrhythmias. Self-administered questionnaires completed at baseline between April 2007 and December 2010 recorded the amount of walking and moderate or vigorous PA. This was converted to metabolic equivalent-minutes per week (MET-min/wk) of activity. Participants with arrhythmias at baseline were excluded. The incidence of arrhythmia was determined by hospital diagnosis or death certificates. Median follow-up was 7 years. Results for men and women were determined separately and together. Hazard ratios were estimated at 500 MET-min/wk increments of PA up to 2500 and also at 5000 MET-min/wk.
The analysis of men and women separately and combined, plus the hazard estimates at multiple PA levels make reading and comprehending this publication arduous, but the authors summarize their results in a “Take home figure”, something I have never seen before, but really appreciated. Afib incidence decreased 5–10% in men and 6–15% in women exercising in the guideline-recommended range of PA, which is 500–1500 MET-min/wk. The afib results are presented separately for men and women because the PA effect was significantly stronger in women. Ventricular arrhythmia incidence also decreased 11–22% for both men and women in the recommended PA levels, with no difference between the sexes. There was no association between PA and brady-arrhythmia for the whole group or either sex. It is noteworthy that vigorous PA between 500–2500 MET-min/wk was associated with lower rates of Afib, but higher doses of vigorous PA in men were associated with a 12% increase in Afib. This supports the idea that the relationship between afib and PA is a “U-shaped curve”.
The main issue with this report is its dependence on hospital records and death certificates to determine the clinical outcome. Arrhythmias not requiring admission would not be detected. It is also always nearly impossible to determine if it’s the PA, or the health of the people who engage in PA, that determined the benefit. The main clinical implication of the report is that the reduction in both afib and ventricular arrhythmias with modest amounts of PA provides another reason to recommend that patients do something physical.
