Objectives: The purpose of this study was to determine the timing of sudden death in patients with advanced heart failure.
Background: The frequency of sudden cardiac death and myocardial infarction is greatest in the morning hours, suggesting that physiologic processes associated with morning activities may trigger these events. In patients with advanced heart failure, a variety of mechanisms may cause sudden death, and the frequency of their occurrence may differ from that in other patient groups, perhaps altering the timing of sudden death in heart failure.
Methods: Deaths among 566 consecutive patients followed up after treatment for advanced heart failure were prospectively categorized as sudden death, death due to heart failure or noncardiac death. For 72 sudden deaths the time of death was determined from witnesses to the event and from death certificates.
Results: Sudden death occurred 2.5 times more frequently between 6:01 AM and 12 noon than in the three other 6-h intervals, with 46% of deaths occurring during this period (p < 0.005). The morning peak occurred both in patients with coronary artery disease and in those with nonischemic causes of heart failure.
Conclusions: Despite a variety of potential mechanisms of sudden death and underlying causes of heart disease in patients with heart failure, the 24-h distribution of sudden death in these patients is similar to that observed in other patient groups. Morning surges in sympathetic nervous system activity may promote a variety of sudden death mechanisms, including ischemic and nonischemic arrhythmias.