Seasonal Variation in Sudden Cardiac Death: Insights from a Large United Kingdom Registry

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Ioannis Panayiotides, Joseph Westaby, Elijah R Behr, Michael Papadakis, Sanjay Sharma, Gherardo Finocchiaro, Mary N Sheppard. Hellenic journal of cardiology. 2024 Jan 19.


Abstract:
Background: Sudden cardiac death (SCD) is relatively common and may occur in apparently healthy individuals. The role of seasonal variation as a risk factor for SCD is poorly understood. The aim of this study was to investigate whether SCD exhibits a predilection for specific seasons.
Methods: We reviewed a database of 4751 cases of SCD (mean age 38 ยฑ 17 years) referred to our center for cardiac pathology at St George’s University of London between 2000 and 2018. Clinical information was obtained from referring coroners who were asked to complete a detailed questionnaire. All cases underwent macroscopic and histological evaluation of the heart, by expert cardiac pathologists.
Results: SCD was more common during winter (26%) and rarer during summer (24%), p= 0.161. Significant seasonal variation was not observed among cases of sudden arrhythmic death syndrome (SADS, 2910 cases) in which the heart is structurally normal. In contrast, a significant difference in seasonal distribution among decedents exhibiting cardiac structural abnormalities at the post-mortem examination (n=1841) was observed. In this subgroup, SCDs occurred more frequently during winter (27 %) compared to summer (22%) (p=0.007). In cases diagnosed with a myocardial disease (n=1399), SCD was most common during the winter (27%) and least common during the summer (22%) (p=0.027).
Conclusions: While SADS occurs throughout the year with no seasonal variation, SCD due to structural heart disease appears to be more common during the winter. Bio-meteorological factors may be potential triggers of SCD in individuals with an underlying structural cardiac abnormality.
Keywords: seasonal variation; sudden cardiac death.