Morning Preference in Onset of Symptomatic Third-Degree Atrio-Ventricular Heart Block

Abstract

The aim of this study was to examine 24h patterning in the symptoms indicative of third-degree atrio-ventricular (AV) heart block. We found a total of 227 cases (126 men and 101 women) of third-degree AV block that had been diagnosed by the Emergency Medical Department of the St. Anna Hospital in Ferrara, Italy between 1990 and 2001. Determination of the hour of onset of symptomatic third-degree AV block, however, was possible and listed in the records of only 161 or 70.9% of the cases (92 men and 69 women). The onset time of every event was categorized into one of four 6h spans of the 24h: night (00:00-05:59h), morning (06:00-11:59h), afternoon (12:00-17:59h), and evening (18:00-23:59h). The onset of the symptoms of third-degree AV block in the sample of 161 cases was significantly greater in the morning between 06:00 and 11:59h than any other 6h span of the day and night (chi2-test; p < 0.001). The same phenomenon was substantiated in the subgroup of the 92 males (chi2; p < 0.0001), although it could not be detected for the smaller subgroup of 69 women. The 24h pattern, with morning preference, in the onset of symptomatic third-degree AV block is similar to the one in sudden cardiac death and cardiogenic cardiac arrest. The etiology of the 24h pattern in symptomatic AV block is unknown; it may be an expression of intrinsic biological rhythmicity within the heart tissue or its control system, and/or the timing of environmental triggers resulting in coronary ischemia.

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.…”

“…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].…”

“…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].…”

Circadian rhythms and cardiovascular health

“…A 24-h pattern, with morning preference, in the onset of symptomatic third-degree AV block was demonstrated in an emergency room setting, 230 similar to the one in SCD and cardiogenic cardiac arrest. 231 The etiology of this 24-h pattern is unknown; it may be an expression of intrinsic biological rhythmicity within cardiac tissue or its control system and/or the timing of environmental triggers culminating in coronary ischemia.…”