Abstract 8115: Circadian Rhythm Pattern of Events in Tako-tsubo Cardiomyopathy

Abstract

Background. Tako-tsubo cardiomyopathy (TTC) is an acute reversible cardiac condition, usually triggered by stressful events, with predilection for older women and a distinctive left ventricular contraction profile. Definition of the diurnal hourly pattern of TTC events may contribute to our understanding of the pathogenesis of this complex entity, but is presently unresolved. Methods. We prospectively enrolled 186 consecutive TTC patients at the Minneapolis Heart Institute and (for comparison) 2,975 patients with ST-segment myocardial infarction (STEMI) over the same time period. Circadian periodicity was analyzed for hourly occurrence of events throughout the 24-hour day, in 4-hour interval blocks. Results. In TTC, the hourly occurrence of events was not uniformly distributed, but showed a distinct and statistically significant afternoon peak between 12:00 pm (noon) and 4:00 pm, comprising 28% of all TTC events, with a nadir at 12 am - 4 am (chi-square = 25.6; p < 0.001), and uninfluenced by age (Figure 1). In contrast, STEMI patients showed a peak occurrence in the early morning hours, 8:00 am to 12:00 noon, comprising 24% of all events (chi-square = 248; p < 0.001), and consistent with prior literature in coronary artery disease. While TTC patients were predominantly female (i.e., 95%), men and women with STEMI showed no difference in circadian pattern. Conclusions. Circadian rhythm of TTC events showed a novel peak in the afternoon hours, distinctive from the STEMI pattern. This hourly timing of TCC events is consistent with environmental factors (i.e., stressful life situations) as the trigger for this condition.