Triggering effect of physical and mental stress on spontaneous ventricular tachyarrhythmias in patients with implantable cardioverter-defibrillators.

BACKGROUND: Physical and mental stress as well as sexual activity are potential triggering factors of acute coronary events and sudden cardiac death. HYPOTHESIS: These factors may also trigger recurrence of spontaneous ventricular tachyarrhythmias in patients with implantable cardioverter-defibrillators (ICDs).
METHODS: We performed a case-crossover study in 43 consecutive patients with 95 symptomatic, ICD-documented tachyarrhythmic events and calculated the relative risk of tachyarrhythmia recurrence during physical and mental stress. Physical and mental activity was graded on a 4-step intensity scale, and stress was defined as physical exertion or mental stress with an intensity grade > or = II during or up to 1 h before arrhythmia recurrence. Relative risk was determined taking into account the habitual weekly stress frequency of each patient.
RESULTS: Physical stress was present in 26% (n = 25), mental stress in 24% (n = 23), and sexual activity in 2% (n = 2) of analyzed events. The weekly habitual stress frequency was 8 +/- 8 (median 7) for physical stress, 6 +/- 6 (median 4) for mental stress, and 0.5 +/- 0.5 (median 0.25) for sexual activity. Thus, relative risk of arrhythmia recurrence during the presence of stress was 7.5 for physical activity (95% confidence interval [CI] 5.2-11.1), 9.5 (CI 6.3-14.5) for mental activity, and 7.5 (CI 2.3-24.8) for sexual activity.
CONCLUSIONS: Physical and mental stress as well as sexual activity are factors that significantly increase relative risk of spontaneous recurrence of sustained ventricular tachyarrhythmias in patients with ICDs. Consideration of this stress-related relative risk increase may contribute to avoidance of harmful shock delivery in ICD recipients.