Circadian, Daily, and Seasonal Distributions of Ventricular Tachyarrhythmias in Patients With Implantable Cardioverter-Defibrillators

Kishlay Anand, Arash Aryana, David Cloutier, Tom Hee, Dennis Esterbrooks, Aryan N. Mooss, Syed M. Mohiuddin

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Abstract

This study investigated the circadian, daily, and seasonal distributions of ventricular arrhythmias in patients with new implantable cardioverter-defibrillator placement at Creighton University Medical Center from January 2000 to December 2004. The incidence and distribution of ventricular tachyarrhythmias as recorded by implantable cardioverter-defibrillators were analyzed with respect to season, month, day of the week, and average daily temperature. Data from 154 consecutive patients (mean age 67 ± 14 years; 78% men, 71% with ischemic heart disease [IHD], mean left ventricular ejection fraction 34 ± 15%) were analyzed. During a mean follow-up of 35 ± 19 months, a total of 1,055 episodes of spontaneously terminated ventricular tachycardia (VT) and 612 episodes of VT or ventricular fibrillation with appropriate device therapy occurred. Distributions in the incidence of VT and VT or ventricular fibrillation receiving appropriate therapy were similar in patients with IHD and non-IHD. Spontaneously terminated VT and appropriately treated VT or ventricular fibrillation episodes occurred with the greatest incidence in the winter months and the lowest incidence in summer, spring, and fall. A linear regression between the number of episodes and the average daily temperature showed a greater likelihood of the 2 events occurring on cooler days, irrespective of the cause of cardiac disease. A weekly distribution was also observed, with the greatest proportion of episodes occurring on Fridays and the lowest on Saturdays and Sundays. A bimodal circadian distribution was present, with the greatest peak occurring from 8 a.m. to 1 p.m. and a smaller peak occurring from 5 p.m. to 10 p.m. In conclusion, the occurrence of ventricular tachyarrhythmias appears to follow circadian, daily, and seasonal distributions that are similar in patients with IHD and non-IHD. The incidence inversely correlates with average daily temperatures.

Original languageEnglish (US)
Pages (from-to)1134-1138
Number of pages5
JournalAmerican Journal of Cardiology
Volume100
Issue number7
DOIs
StatePublished - Oct 1 2007

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All Science Journal Classification (ASJC) codes

  • Cardiology and Cardiovascular Medicine

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