Triggers of clinical coronary heart disease

Major life events as potential triggers of sudden cardiac arrest

BACKGROUND

We investigated the risk of sudden cardiac arrest in association with the recent loss of, or separation from, a family member or friend.

METHODS

Our case-crossover study included 490 apparently healthy married residents of King County, Washington, who suffered sudden cardiac arrest between 1988 and 2005. We compared exposure to spouse-reported family/friend events occurring ≤ 1 month before sudden cardiac arrest with events occurring in the previous 5 months. We evaluated potential effect modification by habitual vigorous physical activity.

RESULTS

Recent family/friend events were associated with a higher risk of sudden cardiac arrest (odds ratio [OR] = 1.6; 95% confidence interval [CI] = 1.1-2.4). ORs for cases with and without habitual vigorous physical activity were 1.1 (0.6-2.2) and 2.0 (1.2-3.1), respectively (interaction P = 0.02).

CONCLUSIONS

These results suggest family/friend events may trigger sudden cardiac arrest and raise the hypothesis that habitual vigorous physical activity may lower susceptibility to these potential triggers.

Triggers of acute cardiovascular events and potential preventive strategies: prophylactic role of regular exercise

There is now considerable evidence to suggest that acute myocardial infarction, sudden cardiac death, and stroke can be triggered by physical, chemical, and psychological stressors, including heavy physical exertion and situations that create heightened emotional stress. The increased risk appears to be largely limited to a susceptible subset of the population, that is, individuals with known or occult cardiovascular (CV) disease. In this article, we summarize the evidence supporting the impact of selected triggers in the pathogenesis of acute CV events, as well as the potential role of various preventive strategies, especially regular exercise training and improvements in cardiorespiratory fitness to reduce the CV risk imposed by various triggers.

Physical activity and incidence of atrial fibrillation in older adults: the cardiovascular health study

BACKGROUND

Vigorous exertion and endurance training have been reported to increase atrial fibrillation (AF). Associations of habitual light or moderate activity with AF incidence have not been evaluated.

METHODS AND RESULTS

We prospectively investigated associations of leisure-time activity, exercise intensity, and walking habits, assessed at baseline and updated during follow-up visits, with incident AF, diagnosed by annual 12-lead ECGs and hospital discharge records, from 1989 to 2001 among 5446 adults > or =65 years of age in the Cardiovascular Health Study. During 47 280 person-years of follow-up, 1061 new AF cases occurred (incidence 22.4/1000 person-years). In multivariable-adjusted analyses, leisure-time activity was associated with lower AF incidence in a graded manner, with 25% (hazard ratio [HR] 0.75, 95% confidence interval [CI] 0.61 to 0.90), 22% (HR 0.78, 95% CI 0.65 to 0.95), and 36% (HR 0.64, 95% CI 0.52 to 0.79) lower risk in quintiles 3, 4, and 5 versus quintile 1 (P for trend <0.001). Exercise intensity had a U-shaped relationship with AF (quadratic P=0.02): Versus no exercise, AF incidence was lower with moderate-intensity exercise (HR 0.72, 95% CI 0.58 to 0.89) but not with high-intensity exercise (HR 0.87, 95% CI 0.64 to 1.19). Walking distance and pace were each associated with lower AF risk in a graded manner (P for trend <0.001); when we assessed the combined effects of distance and pace, individuals in quartiles 2, 3, and 4 had 25% (HR 0.75, 95% CI 0.56 to 0.99), 32% (HR 0.68, 95% CI 0.50 to 0.92), and 44% (HR 0.56, 95% CI 0.38 to 0.82) lower AF incidence than individuals in quartile 1. Findings appeared unrelated to confounding by comorbidity or indication. After evaluation of cut points of moderate leisure-time activity (approximately 600 kcal/week), walking distance (12 blocks per week), and pace (2 mph), 26% of all new AF cases (95% CI 7% to 43%) appeared attributable to absence of these activities.

CONCLUSIONS

Light to moderate physical activities, particularly leisure-time activity and walking, are associated with significantly lower AF incidence in older adults.