Circadian Variation in Sudden Cardiac Death: Effects of Age, Sex, and Initial Cardiac Rhythm

Circadian variation in ventricular tachycardia and atrial fibrillation in a medical-cardiological ICU

“…Most patients were mechanically ventilated with need for continuous analgosedation. Among the cohorts studied so far with respect to a diurnal distribution were patients with myocardial infarction [2], myocardial ischemia [3], sudden cardiac death [5,6,7,8,9], outpatients with ventricular arrhythmias [10,11,12,13,14,15], symptomatic thirddegree atrioventricular block [16] and, supraventricular arrhythmias [17,18]. Thus our study extends previous data to a medical-cardiological critically ill population.…”

“…A clear and significant temporal pattern was also seen for VT. Previous studies on the occurrence of sudden cardiac death and VT reveal a wide variation in time of onset [4,5,6,7,8,9,10,11,12,13,14,15], but most have found a clustering of arrhythmias and sudden cardiac death in the morning and during the day. A nadir during the night is common to all these studies.…”

“…In patients with VT a circadian pattern with a frequency peaks were found between 9 a.m. and 6 p.m. [10], 7 and 11 a.m., 4 and 8 p.m. [11], 2 and 3 p.m. [12], and in the midmorning [12]. Sudden cardiac death and out of hospital, witnessed cardiac arrest clustered between 1 and 2 a.m. [28], in the morning [29], and between 6 and 12 a.m. [8]. Ventricular fibrillation in the Brugada syndrome, as a very specific entity in this context, had a peak occurrence between 6 a.m. and 6 p.m. [13] with a trough in the evening and during the night.…”

“…The evidence of circadian distributions may carry implications for the recognition and treatment of these events. Circadian clustering has been described for myocardial infarction [2], myocardial ischemia [3], stroke [4] sudden cardiac death [5,6,7,8,9], ventricular arrhythmias [10,11,12,13,14,15], symptomatic third-degree atrioventricular block [16], and the inducibility of supraventricular tachycardia [17,18]. Further, circadian variations in sinus rate are present in subjects with normal sinus node function and also partly in those with sinus node dysfunction [19,20].…”

“…With regards to a circadian variation in arrhythmia onset in critically ill patients, data are entirely lacking. This is somewhat surprising in view of the above data on circadian clustering of quite a variety of cardiovascular events [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20].…”