CORRESPONDENCE: LETTER TO THE EDITOR
Reply
Begoña Benito, MD,
Josep Brugada, MD, PhD*,
Ramon Brugada, MD, PhD and
Pedro Brugada, MD, PhD
* The Thorax Institute, Hospital Clinic, Arrhythmia Section, University of Barcelona, Villarroel 170, 08036 Barcelona, Spain (Email: jbrugada{at}clinic.ub.es).
We thank Dr. van den Berg and colleagues for their interest in our article (1) and their valuable comments, which raise important issues regarding the diagnosis of Brugada syndrome. Indeed, a syndrome requires a constellation of symptoms and signs for diagnosis, and a single electrocardiographic finding does not define a syndrome. Dr. van den Berg and colleagues do certainly realize that Brugada syndrome is no longer a syndrome but a disease. After the description of the first mutation in the sodium channel causing Brugada syndrome (2), a multitude of other mutations in the sodium and other channels have been described. It is clear that the consensus report from 2005 (3) is more than outdated and an update is urgently required in terms of both diagnosis and therapeutic approach.
The definite phenotypic manifestation of the Brugada syndrome is the presence of a type-1 electrocardiogram (ECG), either spontaneously or after sodium-blocker challenge. Given that even the sole presence of the ECG pattern has been proven to entail a risk of sudden cardiac death, this was the only prerequisite required in all of our 384 patients included in the study, as stated in the article (1). However, in reply to Dr. van den Berg and colleagues, we must say that most of our patients, both men and women and in similar proportions (82.4% vs. 89.3%, respectively, p = 0.06), did fulfill the II Consensus Report definition of Brugada syndrome. Therefore, the better prognosis in women cannot be explained because of their lower rate of "confirmed diagnosis" according to the consensus. As can be drawn from our article, in addition to the type-1 ECG, 66 of the 272 male patients (24.3%) also had symptoms, 82 (30.1%) had a family history of early sudden death, and 84 (31.9%) had documented ventricular fibrillation either spontaneous or inducible at the time of diagnosis. Because these clinical variables tended to meet within the same individual, they resulted in a total of 148 (54.4%) patients. Additionally, in 74 (27.2%) more men, a type-1 ECG was documented in at least 1 family member. Therefore, at the time of their first evaluation, 222 of 272 patients (81.7%) had a confirmed diagnosis of Brugada syndrome according to the II Consensus definition. On the other hand, a total of 100 of 112 female patients (89.3%) fulfilled the Consensus criteria of Brugada syndrome (62 [55.4%] because of symptoms, family history of sudden death, documented ventricular fibrillation, or a combination, and 38 [33.9%] because of none of the others and a presence of type-1 ECG in family members). Importantly, among the 62 patients (50 men and 12 women) who did not meet the II Consensus definition of Brugada syndrome at the time of first evaluation, 2 men experienced sudden death in follow-up, increasing the total of men with "confirmed diagnosis" to 224 (82.4%). The occurrence of life-threatening events in patients not fulfilling the clinical criteria proposed by the consensus attests to the need to interpret with caution the definition of Brugada syndrome, and also reminds us of the importance of following up all patients even when a type-1 ECG pattern is found in isolation.
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References
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1. Benito B, Sarkozy A, Mont L, et al. Gender differences in clinical manifestations of Brugada syndrome J Am Coll Cardiol 2008;52:1567-1573.[Abstract/Free Full Text]2. Chen Q, Kirsch GE, Zhang D, et al. Genetic basis and molecular mechanism for idiopathic ventricular fibrillation Nature 1998;392:293-296.[CrossRef][Medline] 3. Antzelevitch C, Brugada P, Borggrefe M, et al. Brugada syndrome: report of the Second Consensus Conference: endorsed by the Heart Rhythm Society and the European Heart Rhythm Association Circulation 2005;111:659-670.[Abstract/Free Full Text]
Related Article
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Brugada Syndrome or Brugada Electrocardiogram?
- Maarten P. van den Berg, Rudolf A. de Boer, and J. Peter van Tintelen
J. Am. Coll. Cardiol. 2009 53: 1569.
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