Brugada syndrome with atypical ECG: downsloping ST-segment elevation in inferior leads

We present an unusual case of a young Thai immigrant, symptomatic, who had suffered prior episodes of syncope with strong family background: male, first-degree relatives, younger than 45 years old who had died suddenly. The rest ECG, with the patient asymptomatic at the time, showed persistent ST-segment elevation, in inferior leads and "mirror" image in the anterior wall, which were not modified with sublingual nitrates, in absence of demonstrable structural heart disease by chest X-rays and echocardiogram, hypothermia, ischemia, or electrolytic disorders. Holter monitoring revealed at dawn, a short episode of polymorphic ventricular tachycardia of short onset extrasystole coupling, which evolved into asystole and sudden cardiac death. We believe this is a sudden unexplained death syndrome, although we did not have a chance to conduct a genetic study.     

Prognostic value of electrophysiologic investigations in Brugada syndrome

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.     

Brugada syndrome-like ST-segment elevation increase exacerbated by vomiting.

The patient was a 53 year-old male who had 3 syncopal episodes over a 6-month period. In the electrophysiological study, ventricular fibrillation (VF) was repeatedly induced by the ventricular extrastimulus method. Intravenous pilsicainide was administered, and the J-point and ST-segment in the right precordial leads became slightly elevated just following drug administration. Five min later, the patient experienced severe nausea and then vomited twice, at which point the electrocardiogram (ECG) showed increased elevation of the J-point and ST-segment. These ECG changes recovered to normal 30 min later. The cause of his syncope was strongly suspected to be related to the VF associated with Brugada syndrome. An interesting aspect of this case was the particular type of J-point and ST-segment elevation that was induced when the patient experienced nausea and vomiting. It is proposed that this phenomenon originated from the vagal stimulation associated with the nausea and vomiting.     

Brugada pattern masquerading as ST-segment elevation myocardial infarction in flecainide toxicity

Flecainide (a class 1c antiarrhythmic) produces a dose-dependent decrease in intracardiac conduction. Its well known common electrocardiographic effects are prolongation of PR and QT intervals and the QRS complex duration. We report a case of flecainide toxicity in an elderly female who presented with a type 1 Brugada pattern who essentially had a previously normal ECG pattern on therapeutic dose of flecainide therapy. The case describes a rare electrocardiographic abnormality induced by flecainide toxicity which otherwise could be easily misinterpreted as a ST-segment elevation myocardial infarction (STEMI) without lack of expertise and high clinical suspicion.     

The Brugada syndrome: clinical,electrophysiologic and genetic aspects

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.     

Clinical and electrophysiologic profile of Brugada syndrome in Iranian patients

Clinical and electrophysiologic characteristics of 20 patients (15 males; mean age, 42 +/- 9 years) with Brugada syndrome were studied. Electrocardiographic abnormalities (spontaneous in 6 and provoked in 14) were recognized in 5 symptomatic and 15 asymptomatic patients. Mean PR (188 +/- 18 vs. 184 +/- 24 ms) and QT (362 +/- 34 vs. 382 +/- 28 ms) intervals and ST-segment elevation (2.28 +/- 0.42 vs. 2.70 +/- 0.77 mm) were similar in both groups. The PR interval was slightly longer in males than females (191 +/- 21 vs.168 +/- 18 ms, p = 0.042), but ST-segment elevation (2.70 +/- 0.78 vs. 2.24 +/- 0.26 mm) was similar. The HV interval was longer in males than females (57 +/- 4 vs. 50 +/- 4 ms, p = 0.047). Ventricular arrhythmias were induced in 40% of asymptomatic patients. There was no significant difference in age, sex, PR interval, ST-segment elevation, or HV interval between inducible and non-inducible patients. A defibrillator was implanted in 8 patients. During 16 +/- 2 months of follow-up, one symptomatic patient had appropriate device therapy. None of the asymptomatic and non-inducible patients experienced a cardiac event. Electrophysiologic data have no role in predicting inducibility in programmed stimulation.     

Spontaneous onset of ventricular fibrillation in Brugada syndrome with J wave and ST-segment elevation in the inferior leads.

We report the case of a 52-year-old man with variant Brugada syndrome who was successfully resuscitated from ventricular fibrillation (VF). Resting ECG showed J wave and ST-segment elevation in the inferior leads but no coved or saddleback ST-segment elevation in the right precordial leads. Pilsicainide infusion provoked coved-type ST-segment elevation in the right precordial leads and mild ST-segment elevation 80 ms after the J point in the inferior leads. During an emergency, 12-lead ECG showed that spontaneous onset of VF was preceded by left bundle branch block and superior axis-type ventricular extrasystoles. The present case provides additional information on the site of origin of VF in patients with Brugada syndrome.     

A case of a concealed type of Brugada syndrome with a J wave and mild ST-segment elevation in the inferolateral leads

We report a patient with a concealed type of Brugada syndrome. The electrocardiogram in the emergency department revealed atrial fibrillation with an almost normal ST segment. Slight electrocardiogram abnormalities of the J wave and mild ST-segment elevation appeared in the inferolateral leads a few days later. Although the ST segment in the right precordial leads, including that recorded from the high intercostal space recording sites, was completely normal, a drug challenge test using pilsicainide revealed a coved-type ST-segment elevation only in a modified V2 lead placed 1 or 2 intercostal spaces higher.     

Postprandial augmentation of bradycardia-dependent ST elevation in patients with Brugada syndrome

Introduction : In patients with Brugada syndrome, the circadian variation of ST elevation could be modulated by the autonomic nervous activity and RR interval. Recently, glucose-induced insulin secretion was also reported to contribute to fluctuation of ST elevation. Therefore, we assessed the effects of taking meals on the ST-RR relationship in the daily life of patients with Brugada syndrome.
Methods and Results: Twenty-eight patients with Brugada syndrome, who had the type I ST elevation, were categorized into 12 symptomatic and 16 asymptomatic patients. Unipolar lead (V₂) Holter ECG was recorded and ST-RR relationships for a 2-hour period were compared before and after each meal. From ST-RR linear regression lines, ST-RR slope (mm/sec) and ST(mm) at RR intervals of both 0.6 seconds and 1.2 seconds (ST_(0.6) and ST_(1.2)) were determined. The ST-RR slope increased significantly after lunch (2.6 ± 0.4 vs 4.4 ± 1.2, P < 0.05) and dinner (2.1 ± 1.0 vs 5.2 ± 1.9, P < 0.01) in symptomatic patients, but not in asymptomatic patients. In both groups, ST_(0.6) was not different before or after each meal. However, ST_(1.2) increased after each meal in symptomatic patients. After dinner, ST_(1.2) was significantly higher in symptomatic patients than in asymptomatic patients (5.0 ± 2.7 vs 3.6 ± 0.8, P < 0.05). Postprandial increase in both ST-RR slope and ST_(1.2) was greatest at dinner in symptomatic patients; however, this tendency was not seen in asymptomatic patients.
Conclusions: In symptomatic patients with Brugada syndrome, bradycardia-dependent augmentation of ST elevation was enhanced for the postprandial period, especially after dinner. This could be related to occurrence of ventricular fibrillation in the late evening.     

The Brugada syndrome

The Brugada syndrome is a hereditary disease causing sudden cardiac death in apparently healthy individuals with a structurally normal heart. The disease is caused by mutations in the cardiac sodium channel gene SCN5A. Patients with this disease have a peculiar electrocardiogram with elevation of the ST segment in leads V1 to V3, an electrocardiogram that every doctor should recognize. There exist variants of the electrocardiogram with minimal ST segment elevation and even concealed forms that can only be unmasked by the administration of class I antiarrhythmic drugs. When left untreated or when treated with all known antiarrhythmic drugs, patients with Brugada syndrome have a high mortality (approximately 10% per year). The only effective treatment to prevent sudden death is the implantable defibrillator.