Original-clinicalSeasonal and circadian distributions of ventricular fibrillation in patients with Brugada syndrome
Introduction
Brugada syndrome is an arrhythmogenic disease characterized by a particular electrocardiogram (ECG) pattern with a coved-type ST-segment elevation in the right precordial leads and an increased risk for sudden cardiac death due to ventricular tachyarrhythmias.1, 2, 3, 4, 5, 6 It is well-known that the incidence of ventricular tachyarrhythmias, including ventricular tachycardia (VT) and ventricular fibrillation (VF), is the highest in the winter and during the daytime in patients with structural heart disease.7, 8, 9, 10, 11, 12 In patients with Brugada syndrome, however, the seasonal patterns of the development of malignant ventricular tachyarrhythmias remain unknown, and the circadian patterns have been reported in only a small population.4, 13 Identification of the distribution of VF seems to contribute to a therapy option and the elucidation of the underlying pathophysiology of Brugada syndrome. Therefore, we investigated the seasonal and circadian patterns of VF by analyzing the data stored in an implantable cardioverter-defibrillator (ICD) of patients with Brugada syndrome.
Section snippets
Study population
The study population consisted of 62 consecutive patients with Brugada syndrome (58 men and four women, mean age 48 ± 14 years) who received an ICD between July 1992 and October 2005 at National Cardiovascular Center, Suita, Japan. The following devices were implanted: Medtronic 7217CX, 7221CX, 7223CX, 7227CX, 7228CX, 7229CX, 7230CX, 7036CX, and 7274CX; Guidant 1859, 1860, 1861, and 1790; and CPI 1000, 1600, 1718, and 1742. Brugada syndrome was diagnosed when J-wave amplitude was over 0.2 mV
Patient characteristics and VF episodes
Table 1 shows the clinical characteristics and follow-up data of the 62 patients with Brugada syndrome. Forty-seven (76%) patients had a history of VF/CA/unknown syncope. We could obtain the precise data of the first episodes of VF/CA/unknown syncope before implantation of ICD in 44 patients, and seasonal and circadian distributions of the first episodes of VF/CA/unknown syncope are shown in Figure 1, Figure 2. The seasonal distribution of the first episodes of VF/CA/unknown syncope indicated
Discussion
Our study indicates that there are specific seasonal and circadian variations of the VF episodes in patients with Brugada syndrome, which are quite different from those observed in patients with structural heart disease. There was a significant seasonal peak from spring to early summer and a significant circadian peak from midnight to early morning. The seasonal and circadian variations of electrical storms were similar to those of isolated VF episodes. These findings could be related to the
Conclusion
In patients with Brugada syndrome, there was a significant seasonal peak from spring to early summer and a significant circadian peak from midnight to early morning in terms of the occurrences of VF.
Acknowledgments
We gratefully acknowledge the expert statistical assistance of Akiko Kada.
References (35)
- et al.
Right bundle branch block, persistent ST segment elevation and sudden cardiac death: a distinct clinical and electrocardiographic syndromeA multicenter report
J Am Coll Cardiol
(1992) - et al.
The Brugada syndrome: clinical, electrophysiologic and genetic aspects
J Am Coll Cardiol
(1999) - et al.
Annual distribution of ventricular tachycardias and ventricular fibrillation
Am Heart J
(2003) - et al.
Circadian, daily, and seasonal distributions of ventricular tachyarrhythmias in patients with implantable cardioverter-defibrillators
Am J Cardiol
(2007) - et al.
Circadian variation in the incidence of sudden cardiac death in the Framingham Heart Study population
Am J Cardiol
(1987) - et al.
Acute and chronic management in patients with Brugada syndrome associated with electrical storm of ventricular fibrillation
Heart Rhythm
(2007) - et al.
Seasonal distribution of acute myocardial infarction in the second National Registry of Myocardial Infarction
J Am Coll Cardiol
(1998) - et al.
and the AVID InvestigatorsSeasonal variation of mortality in the Antiarrhythmics Versus Implantable Defibrillators (AVID) study registry
Heart Rhythm
(2004) - et al.
Seasonal variation of endothelin-1, angiotensin II, and plasma catecholamines and their relation to outside temperature
J Lab Clin Med
(2002) - et al.
Catecholamines in children with congenital long QT syndrome and Brugada syndrome
J Electrocardiol
(2001)