A temporal high-risk frame for occurrence of Tako-Tsubo cardiomyopathy?

In their interesting study, Sharkey et al analyzed a cohort of 186 consecutive patients with Tako-tsubo cardiomyopathy (TTC) and 2,975 patients with ST-segment elevation myocardial infarction (STEMI), and identified a circadian pattern with a peak in the early afternoon hours (from 12 noon to 4 P.M.). Again, they analyzed this cohort also by day-of-week and month of the year, and found an uniform distribution throughout the week and the year, although events were most common in December and on Tuesday. These data do not fully agree with previous reports. As for circadian distribution, in their recent systematic review Bossone et al identified four studies addressed to this topic. Only the Italian cohort by Citro et al found an evident morning distribution (6 A.M. to 12 noon). Other studies, performed on limited sample populations, reported statistically non significant diurnal distributions. Again, also day-by-week analysis studies produced variable findings. In fact, Manfredini et al observed a Monday preference of TTC onset in their multicentric cohort of patients in Italy, but Parodi et al did not replicate these results in another population of the same country. Finally, the seasonal summer preference for TTC onset found by Manfredini et al in Italy (n=112), Regnante et al in the Rhode Island Registry (n=70), and Hertting et al in Germany (n=32), received very recently an important support by Deshmukh et al in more than 6,800 cases in the United States, who found a highest peak in July (and a lowest in January). Sharkey et al also confirmed the morning preference for STEMI onset, but found uniform distribution occurrence during the week and the year. Although the former observation provides further confirmation to the topic, the latter is in contrast with the large amount of data indicating a Monday and Winter preference for onset of myocardial infarction. On one hand, studies in different countries with different environments, and performed with different methods for collecting and analyzing temporal data, may at lest in part explain such different results. At now, at least the summer preference for TTC seems to collect convincing data. However, due to the nonuniform findings in recent literature, we recently stated that time of onset does not represent an useful tool in diagnosing TTC19. Nevertheless, the demonstration of temporal windows at enhanced risk of occurrence for TTC, as just for acute cardiovascular diseases, could not represent secondary matter, due to potential implications for possible prevention and temporized treatment. More evidence is so needed, and worldwide clinical studies on TTC should include also data on temporal, i.e., circadian, weekly, or seasonal patterns of occurrence.