Date Published: May 31, 2019
Publisher: Public Library of Science
Author(s): Nina Caroline Peytz, Reza Jabbari, Stig Egil Bojesen, Boerge Nordestgaard, Peter Schnohr, Eva Prescott, Chiara Lazzeri.
While physical activity reduces risk of developing myocardial infarction (MI), it is unknown whether a history of physical activity is also protective of fatal arrhythmia and case-fatality in patients who have suffered an acute MI.
104,801 individuals included in 2003–2014 in the Copenhagen General Population Study (CGPS), a prospective population-based study with self-reported leisure time physical activity (LTPA) in three categories measured at baseline, were followed until 2014 through national registries. The 1,517 individuals who suffered a first time MI during follow-up constituted the study population. Outcomes were fatal MI, defined as date of death same as date of MI (including out-of-hospital deaths) and 28-day fatality. Through multivariable analyses the association between baseline LTPA and outcomes were assessed adjusted for CVD risk factors.
Of 1,517 MI events, 117 (7.7%) were fatal and another 79 (5.6%) lead to death within 28 days. Median time from baseline to MI was 3.6 years (IQR 1.7–5.8). LTPA was associated with lower risk of fatal MI with odds ratios of 0.40 (95% CI: 0.22–0.73) for light and 0.41 (0.22–0.76) for moderate/high LTPA after multivariable adjustment with sedentary LTPA as reference. Age, alcohol-intake, education and smoking were identified as other predictors for fatal MI. We found no association between LTPA and 28-day case fatality.
Among individuals with MI, those that have engaged in any light or moderate physical activity were more likely to survive their MI. Results are consistent with effect of exercise preconditioning on risk of fatal arrhythmia.
Coronary artery disease (CAD) and its consequence, myocardial infarction (MI), are believed to underlie 75% of the deaths of patients who experience sudden cardiac death (SCD) . The greatest risk of SCD in acute MI is in the initial phase after which the risk declines rapidly . It has been estimated that at least two thirds of fatal coronary events occur before the patient reaches a hospital . As a consequence primary prevention is essential to lowering rates of fatal MI.
In this prospective population-based study the main finding was that subjects with MI who were sedentary prior to their cardiac event were more likely to suffer an immediately fatal event. There seemed to be no further cardioprotection with increasing level of physical activity. 28-day MI case fatality was not associated with level of physical activity, but the 28-day case fatality was low.