Brugada Case
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Brugada Case
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Previous yearly ECGs were reported to be normal. The review of ECG from year
1999, however, showed similar but milder abnormalities:
He has never had any symptoms and there was no family history of sudden death. A procainamide challenge showed characteristic aggravation of ST segment
elevations, confirming the diagnosis of Brugada syndrome:
It was a painful decision, but he had to stop flying airplanes. A more difficult decision had to be made about his own further care. The value of electrophysiologic studies in risk stratification of asymptomatic Brugada cases is controversial. There is also a divergence of opinion about the implantation of ICD in such cases. Brugada syndrome was first described in 1992. This syndrome is diagnosed by characteristic ECG changes of right bundle branch block and ST segment elevation from V1-V3 in the context of sudden death (aborted or not) or syncope. Symptoms are attributable to either polymorphic ventricular tachycardia or ventricular fibrillation. It is important to recognize this characteristic ECG pattern as it is a marker for sudden cardiac death. The disease is responsible for up to 4-12% of unexpected sudden deaths and for up to 50% of sudden deaths in patients with a structurally normal heart. The syndrome is estimated to have an autosomal dominant inheritance in 30% of families and no clear pattern of inheritance in 20% of families. The remaining 50% of cases are sporadic, suggesting a "de novo" mutation. Mutations in the SCN5A gene encoding the cardiac sodium channel have been described but not all families with Brugada syndrome have a mutation of this gene, suggesting a heterogeneous genetic disease. Antiarrhythmic drug treatment with amiodarone, However, the optimum management of asymptomatic patients with Brugada syndrome remains controversial, as the natural history of the disease in this group of patients is unclear. According to Brugada, asymptomatic patients recognized at random or discovered in a family study have an 8% incidence of arrhythmic events during a mean follow up of 27 months. Patients with a family history of symptomatic Brugada syndrome and those with persistent but not intermittent ECG changes are reported to have an increased risk of sudden death. This suggests an implantable cardioverter-defibrillator to be appropriate treatment for some or all of the asymptomatic cases. However, against this is a study from Priori group showing 0% cardiovascular mortality of asymptomatic patients with Brugada syndrome over a mean follow up period of 49 months.
Long-term follow-up of individuals with the electrocardiographic pattern of right bundle-branch block and ST-segment elevation in precordial leads V1 to V3. Brugada J, Brugada R, Antzelevitch C, Towbin J, Nademanee K, Brugada P. Circulation 2002 Jan 1;105(1):73-8 BACKGROUND: The electrocardiographic pattern of right bundle-branch block with ST-segment elevation in leads V1 to V3 is increasingly recognized among patients who have aborted sudden cardiac death, but also in asymptomatic individuals, raising questions about its prognostic significance. METHODS AND RESULTS: The clinical, electrophysiological, and follow-up data of 334 patients with the Brugada phenotype were analyzed. A total of 79 women and 255 men with a mean age at diagnosis of 42+/-16 years were studied. The abnormal ECG was recognized after a resuscitated cardiac arrest in 71 patients (group A), after a syncopal episode in 73 patients (group B), and in 190 asymptomatic individuals (group C). Sustained ventricular arrhythmias were inducible in 83%, 63%, and 33% of patients in group A, group B, and group C, respectively. During 54+/-54 and 26+/-36 months of follow-up, respectively, 62% of patients in group A and 19% of group B patients had a new arrhythmic event. Inducibility of ventricular arrhythmias was the only predictor of arrhythmia occurrence in both groups. During a mean follow-up of 27+/-29 months, 8% of group C individuals had a first arrhythmic event. In these individuals, inducibility of ventricular arrhythmias and a basal abnormal ECG were predictors of arrhythmia occurrence. CONCLUSIONS: An ECG showing right bundle-branch block and ST-segment elevation in the right precordial leads is a marker of malignant ventricular arrhythmias and sudden death. Recurrence of malignant arrhythmias is high after the occurrence of symptoms. Among asymptomatic individuals, those with a spontaneously abnormal ECG and inducible to ventricular arrhythmias have the poorer prognosis.
Asymptomatic patients with a brugada electrocardiogram: are they at risk? J Cardiovasc Electrophysiol 2001 Jan;12(1):7-8
Three-year follow-up of
patients with right bundle branch block and ST segment elevation in the right
precordial leads: Japanese Registry of Brugada Syndrome. Idiopathic Ventricular
Fibrillation Investigators.
J Am Coll Cardiol 2001 Jun 1;37(7):1916-20
Brugada syndrome: manifest, concealed, "asymptomatic," suspected and simulated. Surawicz B. J Am Coll Cardiol 2001 Sep;38(3):775-7
Prognostic value of electrophysiologic investigations in Brugada syndrome. Brugada P, Geelen P, Brugada R, Mont L, Brugada J. J Cardiovasc Electrophysiol 2001 Sep;12(9):1004-7 INTRODUCTION: The prognostic value of electrophysiologic investigations in individuals with Brugada syndrome is unclear. Previous studies failed to determine its value because of a limited number of patients or lack of events during follow-up. We present data on the prognostic value of electrophysiologic studies in the largest cohort ever collected of patients with Brugada syndrome. METHODS AND RESULTS: Two hundred fifty-two individuals with an ECG diagnostic of Brugada syndrome were studied electrophysiologically. The diagnosis was made because of a classic ECG with a coved-type ST segment elevation in precordial leads V1 to V3. Of the 252 individuals, 116 had previously developed spontaneous symptoms (syncope or aborted sudden cardiac death) and 136 were asymptomatic at the time of diagnosis. A sustained ventricular arrhythmia was induced in 130 patients (51%). Symptomatic patients were more frequently inducible (73%) than asymptomatic individuals (33%) (P = 0.0001). Fifty-two individuals (21%) developed an arrhythmic event during a mean follow-up of 34 +/- 40 months. Inducibility was a powerful predictor of arrhythmic events during follow-up both in symptomatic and asymptomatic individuals. Overall accuracy of programmed ventricular stimulation to predict outcome was 67%. Overall accuracy in asymptomatic individuals was 70.5%, with a 99% negative predictive value. Overall accuracy in symptomatic patients was 62%, with only a 4.5% false-negative rate. No significant differences were found in the duration of the H-V interval during sinus rhythm between symptomatic or asymptomatic individuals. However, the H-V interval was significantly longer in the asymptomatic individuals who became symptomatic during follow-up compared with those who did not develop symptoms (59 +/- 8 msec vs 48 +/- 11 msec, respectively; P = 0.04). CONCLUSION: Inducibility of sustained ventricular arrhythmias is a good predictor of outcome in Brugada syndrome. In asymptomatic individuals, a prolonged H-V interval during sinus rhythm is associated with a higher risk of developing arrhythmic events during follow-up. Symptomatic patients require protective treatment even when they are not inducible. Asymptomatic patients can be reassured if they are noninducible.
Prevalence of
asymptomatic ST segment elevation in right precordial leads with right bundle
branch block (Brugada-type ST
shift) among the general Japanese population. Heart 2001 Aug;86(2):161-6 OBJECTIVE: To examine the modality and morbidity of asymptomatic ST segment elevation in leads V1 to V3 with right bundle branch block (Brugada-type ST shift). METHODS: 8612 Japanese subjects (5987 men and 2625 women, mean age 49.2 years) who underwent a health check up in 1997 were investigated. Those with Brugada-type ST shift underwent the following further examinations over a two year period after the initial check up: ECG, echocardiogram, 24 hour Holter monitoring, treadmill exercise testing, signal averaged ECG, and slow kinetic sodium channel blocker loading test (cibenzoline, 1.4 mg/kg). RESULTS: Asymptomatic Brugada-type ST shift was found in 12 of 8612 (0.14%) subjects. Eleven of these 12 subjects were followed up. Follow up ECG exhibited persistent Brugada-type ST shift in seven of 11 (63.6%) subjects. ST shift was transformed from a saddle back to a coved type in three subjects. None of the subjects had morphological abnormalities or abnormal tachyarrhythmias. Positive late potentials were found in seven of 11 (63.6%) subjects. Augmentation of ST shift was shown by both submaximal exercise and drug administration in one of the 11 subjects (9.1%). CONCLUSIONS: Asymptomatic subjects with Brugada-type ST shift were not unusual, at a rate of 0.14% in the general Japanese population. Almost all of the subjects had some abnormalities in non-invasive secondary examinations. Additional and prospective studies are needed to confirm the clinical significance and the prognosis of asymptomatic Brugada-type ST shift.
Sudden death in high-risk family members: Brugada syndrome. Brugada P, Brugada R, Brugada J. Am J Cardiol 2000 Nov 2;86(9 Suppl 1):K40-K43 Brugada syndrome (an electrocardiographic pattern of right bundle branch block, ST segment elevation in leads V1 to V3, and sudden death) is genetically determined and caused by mutations in the cardiac ion channels. The mode of inheritance of the disease is autosomal dominant in half of familial forms. Sudden death may, however, occur from a variety of causes in relatives and patients with this syndrome. Twenty-five Flemish families with this syndrome with a total of 334 members were studied. Affected members were recognized by means of the typical electrocardiogram of the syndrome, either occurring spontaneously or after the intravenous administration of antiarrhythmic drugs. Sudden deaths in these families were classified as related or not to the syndrome by analysis of the data at the time of the event, mode of inheritance of the disease, and data provided by survivors. Of the 25 families with the syndrome, 18 were symptomatic (at least 1 sudden death related to the syndrome) and 7 were asymptomatic (no sudden deaths related to the syndrome). In total, there were 42 sudden cardiac deaths (12% incidence). Twenty-four sudden deaths were related to the syndrome and all happened in symptomatic families. Eighteen sudden deaths (43% of total sudden deaths) were not related to the syndrome (9 cases) or were of unclear cause (9 cases). Three of them occurred in 2 asymptomatic families and the remaining 15 in 5 symptomatic families. A total of 24 of the 50 affected members (47%) and 18 of the 284 unaffected members (6%) had aborted sudden death. This difference in the incidence of sudden death was statistically significant (p <0.0001). Patients with aborted sudden death caused by the syndrome were younger than patients with sudden death of other or unclear causes (38 +/- 4 years vs 59 +/- 3 years respectively; p = 0.0003). In families at high risk of sudden death because of genetically determined diseases, the main cause of sudden death remains the disease itself. However, almost half of sudden deaths are caused by unrelated diseases or from unclear causes. Accurate classification of the causes of sudden death is mandatory for appropriate analysis of the causes of death when designing preventive treatments.
Clinical and genetic heterogeneity of right bundle branch block and ST-segment elevation syndrome: A prospective evaluation of 52 families. Priori SG, Napolitano C, Gasparini M, Pappone C, Della Bella P, Brignole M, Giordano U, Giovannini T, Menozzi C, Bloise R, Crotti L, Terreni L, Schwartz PJ. Circulation 2000 Nov 14;102(20):2509-15 BACKGROUND: The ECG pattern of right bundle branch block and ST-segment elevation in leads V(1) to V(3) (Brugada syndrome) is associated with high risk of sudden death in patients with a normal heart. Current management and prognosis are based on a single study suggesting a high mortality risk within 3 years for symptomatic and asymptomatic patients alike. As a consequence, aggressive management (implantable cardioverter defibrillator) is recommended for both groups. METHODS AND RESULTS: Sixty patients (45 males aged 40+/-15 years) with the typical ECG pattern were clinically evaluated. Events at follow-up were analyzed for patients with at least one episode of aborted sudden death or syncope of unknown origin before recognition of the syndrome (30 symptomatic patients) and for patients without previous history of events (30 asymptomatic patients). Prevalence of mutations of the cardiac sodium channel was 15%, demonstrating genetic heterogeneity. During a mean follow-up of 33+/-38 months, ventricular fibrillation occurred in 5 (16%) of 30 symptomatic patients and in none of the 30 asymptomatic patients. Programmed electrical stimulation was of limited value in identifying patients at risk (positive predictive value 50%, negative predictive value 46%). Pharmacological challenge with sodium channel blockers was unable to unmask most silent gene carriers (positive predictive value 35%). CONCLUSIONS: At variance with current views, asymptomatic patients are at lower risk for sudden death. Programmed electrical stimulation identifies only a fraction of individuals at risk, and sodium channel blockade fails to unmask most silent gene carriers. This novel evidence mandates a reappraisal of therapeutic management.
The Brugada syndrome: clinical, electrophysiologic and genetic aspects. Gussak I, Antzelevitch C, Bjerregaard P, Towbin JA, Chaitman BR. J Am Coll Cardiol 1999 Jan;33(1):5-15 This review deals with the clinical, basic and genetic aspects of a recently highlighted form of idiopathic ventricular fibrillation known as the Brugada syndrome. Our primary objective in this review is to identify the full scope of the syndrome and attempt to correlate the electrocardiographic manifestations of the Brugada syndrome with cellular and ionic heterogeneity known to exist within the heart under normal and pathophysiologic conditions so as to identify the cellular basis and thus potential diagnostic and therapeutic approaches. The available data suggest that the Brugada syndrome is a primary electrical disease resulting in abnormal electrophysiologic activity in right ventricular epicardium. Recent genetic data linking the Brugada syndrome to an ion channel gene mutation (SCN5A) provides further support for the hypothesis. The electrocardiographic manifestations of the Brugada syndrome show transient normalization in many patients, but can be unmasked using sodium channel blockers such as flecainide, ajmaline or procainamide, thus identifying patients at risk. The available data suggest that loss of the action potential dome in right ventricular epicardium but not endocardium underlies the ST segment elevation seen in the Brugada syndrome and that electrical heterogeneity within right ventricular epicardium leads to the development of closely coupled premature ventricular contractions via a phase 2 reentrant mechanism that then precipitates ventricular tachycardia/ventricular fibrillation (VT/VF). Currently, implantable cardiac defibrillator implantation is the only proven effective therapy in preventing sudden death in patients with the Brugada syndrome and is indicated in symptomatic patients and should be considered in asymptomatic patients in whom VT/VF is inducible at time of electrophysiologic study. |
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blockers,
or both does not prevent sudden cardiac death in Brugada syndrome and therefore
current recommendations suggest use of an implantable cardioverter defibrillator
in symptomatic patients.