Assessment of markers for identifying patients at risk for life-threatening arrhythmic events in Brugada syndrome

INTRODUCTION: Risk stratification for life-threatening arrhythmic events in Brugada syndrome is not yet established. The aim of the present study was to examine the usefulness of various markers in predicting life-threatening arrhythmic events in the Brugada syndrome. METHODS AND RESULTS: Forty-six patients with Brugada-type ECGs were categorized into the symptomatic (n=28) and asymptomatic (n=18) groups. Statistical analyses were performed with respect to the usefulness of the following markers: SCN5A mutation, pharmacologic challenge, ventricular fibrillation (VF) inducibility by programmed electrical stimulation, and late potential (LP) by signal-averaged ECG (SAECG). Comparison between the two groups revealed a significant difference only in LP positivity (92.6% vs 47.1%, P=0.0004). The symptomatic group had significantly lower RMS40, longer LAS40, and longer fQRSd compared with the asymptomatic group. A significant difference was noted, especially RMS40. The positive predictive value, negative predictive value, and predictive accuracy when setting a cutoff value of 15 microV were 92.0%, 78.9%, and 86.4%, respectively. Furthermore, patients with an RMS40 value <15 microV (n=25) showed significantly higher rates of VF recurrence compared with patients with an RMS40 value > or = 15 microV (n=19, P=0.047). CONCLUSION: Regarding risk stratification for identifying high-risk patients in Brugada syndrome, only LP by SAECG was shown to be useful, suggesting the importance of RMS40 in predicting the history of life-threatening arrhythmic events and the recurrence of VF.     

Double SCN5A mutation underlying asymptomatic Brugada syndrome

OBJECTIVES: The purpose of this study was to identify risk markers in patients with Brugada syndrome. BACKGROUND: Patients with Brugada syndrome who experience syncope or aborted sudden death are at high risk for recurrent lethal arrhythmias. The prognosis and therapeutic approaches in asymptomatic individuals with a Brugada-type ECG (asymptomatic Brugada syndrome) are controversial. METHODS: We genetically screened 30 asymptomatic probands (29 men and 1 woman; mean age 47.1 years) exhibiting a spontaneous Brugada-type ECG. Family members of patients with Brugada syndrome were excluded from the study. RESULTS: Twenty-nine of 30 patients (96.7%) remained symptom-free for at least 3 years. One patient (case 1) with a family history of sudden death died suddenly during sleep. Ventricular fibrillation was induced by programmed electrical stimulation in 14 of 18 subjects (78%), but none of these 18 subjects developed spontaneous ventricular arrhythmias. Genetic screening failed to identify SCN5A mutations in most cases but demonstrated a novel double missense mutation (K1527R and A1569P) located on the same allele in another asymptomatic subject (case 2). Heterologously expressed mutant Na channels exhibited a negative shift of steady-state inactivation (9.2 mV) and enhanced slow inactivation, suggesting this individual harbors a subclinical channel dysfunction compatible with symptomatic Brugada syndrome. CONCLUSIONS: Asymptomatic individuals with a Brugada-type ECG generally have a better prognosis than their symptomatic counterparts, but a subgroup of these individuals may have a poor prognosis. Severe Na channel dysfunction as a result of SCN5A mutations may not be sufficient to cause symptoms or arrhythmias in patients with Brugada syndrome, suggesting unknown factors or modifier genes influence arrhythmogenesis.     

Prevalence of Brugada sign in patients presenting with palpitation in southern Iran.

AIMS: Brugada syndrome is a cardiac channel abnormality that is associated with a high risk of ventricular fibrillation and sudden cardiac death and characterized by an electrocardiographic pattern of right bundle branch block and transient or persistent ST-segment elevation in leads V1-V3. No data regarding the frequency of Brugada syndrome exist in an Iranian population. The aim of this study was to determine the frequency of Brugada-type ECG pattern in southern Iran. METHODS AND RESULTS: All patients presenting with palpitation were enrolled in the study. A Brugada-type ECG pattern was determined according to the criteria recommended by European Heart Association Molecular Basis of Arrhythmias Study Group. A total of 3895 patients (mean age 38.2 +/- 11.9 years, 54% women) met all study criteria. One hundred patients (2.56%) had Brugada-type ECG pattern. Of these, 21 patients (0.54%) had definite Brugada sign (Type 1 or Types 2 and 3 with conversion to Type 1 following procainamide test). Of 21 patients with definite Brugada sign, eight had Brugada syndrome, four had history of syncope, two had coved-type ECG in the family, one had polymorphic ventricular tachycardia, and one had history of sudden cardiac death in the family. Five patients underwent ICD implantation. The incidence of a Brugada-type ECG pattern was 2.43% in subjects between 17 and 30 years and 0.13% in subjects >30 years (P = 0.01). CONCLUSION: Frequency of Brugada sign in an Iranian population presenting with palpitation is greater than some European countries and lower than a Japanese urban population.     

Brugada electrocardiographic pattern induced by fever

Brugada syndrome is a major cause of sudden death in young adults.Fever has been described to induce a Brugada-type electrocardiogram in asymptomatic patients with a negative family history,to disclose Brugada syndrome and to increase the risk of death and induce T wave alternans in patients with diagnosed Brugada syndrome.Risk stratification is challenging and demands a careful evaluation.Here we present 2 case reports and review the literature.     

健康人高位右侧胸前导联Brugada心电图征调查

目的 初步了解我国健康人高位右侧胸前导联Brugada心电图征发生率及其意义。方法 对1005例健康体检者进行病史询问、体格检查、X线胸片、标准12导联和第二肋间右侧胸前导联心电图检查,按照欧洲心脏病学会制定的标准筛选Brugada心电图征。结果 排除4例器质性心脏病和心律失常患者后,共1001例（男877例,女124例）人选,年龄17～75（28．3±14．8）岁。标准导联心电图检查发现5例2型Brugada心电图征（0．5％）,第二肋间右侧胸前导联心电图检查发现47例Brugada心电图征（4．70％）,均为男性（2型40例,3型7例）。无不明原因晕厥或黑噱史,无猝死家族史。结论 对于症状不典型者,依据标准导联或高位右侧胸前导联2型或3型Brugada心电图征诊断Brugada综合征要慎重。     

Risk stratification in patients with Brugada syndrome: analysis of daily fluctuations in 12-lead electrocardiogram (ECG) and signal-averaged electrocardiogram (SAECG)

Introduction: Risk stratification between symptomatic and asymptomatic patients with Brugada syndrome is not yet established. We compared daily fluctuations in 12-lead electrocardiogram (ECG) and signal-averaged ECG (SAECG) characteristics between symptomatic and asymptomatic patients with Brugada syndrome to identify new markers for distinguishing between high- and low-risk patients.
Methods and Results: Thirty-five patients with Brugada syndrome underwent ECG and SAECG simultaneously at least 4 times every 3 months. We evaluated daily fluctuations (differences between maximum and minimum values) in ECG and SAECG characteristics and compared them between symptomatic  (N = 11)  , and asymptomatic  (N = 24)  patients. On ECG, the daily fluctuations in r-J interval (interval from QRS onset to J point) in leads V1, V2, and V6 were significantly larger in symptomatic than in asymptomatic patients  (V1; 20 ± 6 vs 10 ± 8 msec, P < 0.01, V2; 22 ± 8 vs 11 ± 4 msec, P < 0.01, and V6; 24 ± 7 vs 14 ± 7 msec, P < 0.01)  . On SAECG, daily fluctuations in filtered QRS (f-QRS) duration and LAS40 were significantly larger in symptomatic than in asymptomatic patients (f-QRS;  15 ± 7 vs 9 ± 4 msec, P < 0.05  , and LAS40;  21 ± 7 vs 10 ± 6 msec, P < 0.05  ).
Conclusions: Instability of depolarization appears to be related to the risk of fatal ventricular arrhythmias in patients with Brugada syndrome. Daily fluctuations in ECG and SAECG characteristics could be useful for distinguishing between high- and low-risk patients with Brugada syndrome.     

Long-term follow-up in patients with Brugada Syndrome in South China

ObjectiveTo evaluate the presence of Brugada electrocardiogram (ECG) pattern, clinical characteristics, treatment, and long‐term prognosis of Brugada syndrome in southern Chinese population.MethodsThis prospective study consisted of a consecutive series of patients with diagnostic coved type I Brugada ECG pattern at baseline between January 2007 and February 2020. Histories of symptoms including ventricular tachycardia (VT)/ventricular fibrillation (VF) episode, syncope, and family history of Brugada Syndrome (BrS) or unexplained sudden cardiac death were collected. Electrophysiological study and implantable cardioverter‐defibrillator (ICD) were performed. All patients included in this study were followed up in the outpatient department every 6 months after baseline evaluation. Occurrences of syncope, VF, and sudden death were independently analyzed by two cardiologists.Results45 (56.3%) patients were diagnosed with BrS. During a mean follow‐up of 7.9 ± 3.6 years, six patients had experienced documented VF/sudden cardiac death (SCD) or recurrent syncope. Two patients experienced episodes of syncope more than once. Two patients experienced onset of electrical storm with a total of 11 episodes of VF. There were 50% of these events occurring in fever status. One of patient with BrS died of SCD.ConclusionThere was a very low prevalence of Brugada syndrome in southern Chinese population. The risk of arrhythmic events was low in asymptomatic patients. ICD was high effective in preventing SCD without adverse device outcome in long‐term follow‐up. Fever can lead to predispose to malignant arrhythmia, and aggressive treatment of febrile state in Brugada syndrome was recommended.     

Electrocardiographic and electrophysiologic characteristics in patients with Brugada type electrocardiogram and inducible ventricular fibrillation: single center experience.

BACKGROUND: The study examined the electrocardiographic and electrophysiologic characteristics in relation to programmed ventricular stimulation (PVS)-induced ventricular fibrillation (VF) in patients with Brugada syndrome. METHODS AND RESULTS: Thirty-four patients with a Brugada-type electrocardiogram (ECG) were enrolled. Twelve patients had a type 1 ECG, 12 had a type 2 ECG, and 10 had a type 3 ECG. PVS was performed with up to 2 ventricular premature beats from the right ventricular apex and outflow tract at 2 basic cycle lengths (600 and 400 ms). VF was induced in 17 of 23 (74%) asymptomatic patients and 10 of 11 (91%) symptomatic patients (p<0.05). The 27 patients in whom VF was induced by PVS and 7 patients without inducible VF were followed up for 47.1+/-33.7 months. One sudden death occurred during the follow-up period among asymptomatic patients with inducible VF, and no sudden death occurred among patients without inducible VF. CONCLUSIONS: In conclusion, inducibility of ventricular arrhythmia is high in patients with Brugada syndrome, but it does not correlate with clinical presentation. Few arrhythmic events occur during follow up. However, the present study data suggest that electrophysiologic study-induced VF does not predict arrhythmic events during follow up.     

普罗帕酮试验引起Brugada综合征心室颤动(附一例报告)

探索普罗帕酮试验在Brugada综合征中的作用及安全性。患者有家族性夜间猝死史 ,近 1 9个月来反复发作性夜间晕厥5次 ,两次猝死未遂 ,一次记录到的心电图为心室颤动 (VF) ,其超声心动图、冠状动脉造影、左右心室造影正常 ,电生理检查心脏传导系统功能正常 ,右心室程序电刺激可诱发VF ,诊断不明。静脉用普罗帕酮 2mg/kg后 30min出现典型Brugada综合征心电图改变 ,并诱发VF。结论 :普罗帕酮可作为诊断Brugada综合征的工具 ,同时应警惕其致心律失常作用     

Brugada phenocopy in a patient with unstable angina and three-vessel coronary artery disease

A 52-year-old male was admitted with unstable angina and three-vessel coronary artery disease. Electrocardiography (ECG) changes consistent with type-1 Brugada ECG pattern were noted during admission. The patient was asymptomatic for syncope and had no family history of sudden cardiac death, ICD implantation, and Brugada syndrome. After coronary by-pass graft the Brugada ECG pattern resolved, and ajmaline test did not elicit type-1 ECG pattern, confirming the suspicion of Brugada phenocopy.     

Natural history of Brugada syndrome: the prognostic value of programmed electrical stimulation of the heart

INTRODUCTION: The prognostic value of electrophysiologic studies in individuals with the syndrome of right bundle branch block and ST segment elevation in precordial leads V1 to V3 (Brugada syndrome) remains controversial. Our previous data from 252 individuals with the syndrome suggested that programmed ventricular stimulation had a good overall accuracy to predict events. However, studies from independent investigators questioned our results. We report here the largest population with Brugada syndrome ever studied by programmed electrical stimulation of the heart. METHODS AND RESULTS: Four hundred forty-three individuals with an ECG diagnostic of Brugada syndrome were studied by programmed electrical stimulation of the heart. The diagnosis was made because of the classic ECG showing a coved-type ST segment elevation in precordial leads V1 to V3. Of the 443 individuals, 180 had developed spontaneous symptoms (syncope or aborted sudden cardiac death) and 263 were asymptomatic at the time the diagnosis was made. The ventricular stimulation protocol included a minimum of two basic pacing cycle lengths with two ventricular premature beats from the right ventricular apex. A sustained ventricular arrhythmia was induced in 217 cases (49%). Symptomatic patients were more frequently inducible [126/180 (70%)] than asymptomatic individuals [91/263 (34%); P = 0.0001]. Males were more frequently inducible than females (54% vs 32%, P < 0.0001). Inducible individuals had a longer HV interval than noninducible patients (50 +/- 12 msec vs 46 +/- 10 msec, P < 0.002). HV interval and number of premature beats needed to induce VF were not related to outcome. Inducibility was statistically a powerful predictor of arrhythmic events during follow-up. Sixty of 217 inducible patients (28%) had spontaneous ventricular fibrillation compared with 5 of 221 noninducible patients (2%; P = 0.0001). CONCLUSION: Inducibility of sustained ventricular arrhythmias during programmed ventricular stimulation of the heart is a good predictor of outcome in Brugada syndrome.     

Clinical significance of macroscopic T-wave alternans after sodium channel blocker administration in patients with Brugada syndrome

Introduction:  Macroscopic T-wave alternans (TWA) is sometimes observed after sodium channel blocker administration in patients with Brugada syndrome (BS), but little is known about the association between occurrence of TWA and clinical characteristics in BS patients. We investigated the association between spontaneous ventricular fibrillation (VF) occurrence and TWA after pilsicainide, a sodium channel blocker administration in BS patients.
Methods and Results:  We administered pilsicainide at a dose of 1 mg/kg to 77 BS patients (76 males and one female; mean age, 48.4 years) and examined the association between TWA after pilsicainide administration and clinical characteristics, including age, spontaneous VF, syncope, family history of sudden death, spontaneous coved ST elevation, late potentials (LP), induction of VF by programmed electrical stimulation, and SCN5A mutation. None of the patients had TWA before pilsicainide administration, but TWA became apparent in 17 (22.1%) of the patients after pilsicainide administration. Patients with TWA had a significantly higher incidence of spontaneous VF (52.9% vs 8.3%, P < 0.001) and syncope (58.8% vs 26.7%, P < 0.05) than did patients without TWA. Then, we focused on the association between spontaneous VF and clinical characteristics. Patients with spontaneous VF had a significantly higher incidence of TWA (64.3% vs 12.7%, P < 0.001) and LP positive (92.9% vs 56.5%, P < 0.01) than did patients without spontaneous VF. In multivariate analysis, TWA (P = 0.001) and LP (P = 0.047) appeared as the independent predictor for spontaneous VF.
Conclusion:  TWA after pilsicainide administration is associated with a high risk of clinical VF in patients with BS.     

Relationship between dominant prolongation of the filtered QRS duration in the right precordial leads and clinical characteristics in Brugada syndrome

Background: Electrical abnormalities in the RVOT may be involved in Brugada syndrome.
Objectives: We investigated the relationship between the signal-averaged ECG (SAECG) and electrophysiologic study (EPS), especially focusing on conduction delay in the outflow tract of the right ventricle (RVOT) and its contribution to clinical characteristics.
Methods: Twenty-four patients with Brugada syndrome (23 men and 1 woman; 61 ± 16 years old) were studied. We assessed the presence of late potential (LP) in SAECG and the filtered QRS duration in the right precordial leads (V₁ or V₂; RfQRS) and in the left precordial leads (V₅ or V₆; LfQRS) and the difference between them. In 18 patients, SAECG was evaluated for an LP on three separate occasions.
Results: SAECG was positive for LP in 15 patients at least once; and in 7 patients, SAECG was positive for an LP on multiple occasions, and 6 of 7 patients (86%) had a history of cardiac arrest. The difference between RfQRS and LfQRS was significantly greater in patients with cardiac arrest than in patients with syncope or in asymptomatic patients; 29 ± 10, 14 ± 11 (P < 0.01), and 7 ± 5 msec (P < 0.001), respectively. All patients were alive and one patient with cardiac arrest had an appropriate VF therapy delivered by the ICD.
Conclusions: The dominant prolongation of the filtered QRS duration in the right precordial leads may be related to the risk of arrhythmic event in Brugada syndrome.     

Asymptomatic Brugada Syndrome Case Unmasked During Dimenhydrinate Infusion

Typical ECG of that described for Brugada syndrome was elicited in a patient diagnosed with labyrinthopathy during infusion of dimenhydrinate, a first-generation antihistamine usually used to treat motion sickness. Although the patient had no history of syncope or palpitations, and there was no family history of cardiac disease or sudden death, the ECG abnormality was reproduced later with intravenous flecainide, and an asymptomatic Brugada syndrome was diagnosed.     

High-frequency potentials developed in wavelet-transformed electrocardiogram as a novel indicator for detecting Brugada syndrome

BACKGROUND: A reliable alternative method for detecting Brugada syndrome is desirable because the diagnosis of Brugada syndrome using 12-lead ECG is not optimal. OBJECTIVES: The purpose of this study was to assess the usefulness of the wavelet-transformed ECG in detecting Brugada syndrome. METHODS: The study consisted of 15 patients with Brugada syndrome and 15 healthy subjects (control group). The parameters on the signal-averaged ECG and the frequency components recorded from the wavelet-transformed ECG were compared between the two groups. Measurements were repeated after pilsicainide infusion in the two groups of patients, after an isoproterenol infusion following pilsicainide injection, and after administration of cilostazol in the group of patients with Brugada syndrome. RESULTS: The positive rate of late potentials was 80% in the Brugada syndrome group and 0% in the control group (P <.01). The high-frequency components (80-150 Hz) were developed in the Brugada syndrome group to a greater extent than in the control group, but the low-frequency components (10-50 Hz) did not differ (mean peak power at 80 Hz; 713 +/- 36 vs 488 +/- 60, P <.001). After pilsicainide injection, high-frequency components significantly increased in both groups. However, after isoproterenol and cilostazol administration, high-frequency components significantly decreased but remained higher than in the control group (80 Hz; 655 +/- 40 vs 488 +/- 60, P <.001). The sensitivity of the development of high-frequency components in detecting Brugada syndrome was higher than that of signal-averaged ECG (100% vs 80%), but specificity remained high and similar (100% for both methods). CONCLUSION: Abnormally high-frequency components recorded from the wavelet-transformed ECG might be a novel factor in detecting Brugada syndrome.     

The prevalence, incidence and prognostic value of the Brugada-type electrocardiogram: a population-based study of four decades

OBJECTIVES: We sought to demonstrate the prevalence, incidence and prognostic value of the Brugada-type electrocardiogram (ECG) in a general population. BACKGROUND: The Brugada syndrome is characterized by evidence of right bundle branch block and ST segment elevation in the right precordial leads, as well as sudden death caused by ventricular fibrillation. However, the natural history of the Brugada-type ECG remains unclear. METHODS: We investigated 4,788 subjects (1,956 men and 2,832 women) who were <50 years old in 1958 and had undergone biennial health examinations, including electrocardiography, through 1999. The Brugada-type ECG was defined as a terminal r' wave in lead V(1) and ST segment elevation > or =0.1 mV in leads V(1) and V(2). Unexpected death was defined as sudden death or unexplained accidental death. RESULTS: There were a total of 32 Brugada-type ECG cases; the prevalence and incidence were 146.2 in 100,000 persons and 14.2 persons per 100,000 person-years, respectively. The incidence was nine times higher among men than women, and the average age at presentation was 45 +/- 10.5 years. The Brugada-type ECG appeared intermittently in most cases and was found in 26% of subjects who died unexpectedly. Cox survival analysis revealed that mortality from unexpected death was significantly higher in subjects with a Brugada-type ECG than in control subjects (p < 0.01). Unexpected deaths were more frequent among subjects with the Brugada-type ECG who had a history of syncope (p < 0.05). CONCLUSIONS: The Brugada-type ECG is not a very rare condition in the adult Japanese population. Subjects with a Brugada-type ECG have an increased risk of unexpected death.     

Vagal activity modulates spontaneous augmentation of ST elevation in the daily life of patients with Brugada syndrome

INTRODUCTION: In Brugada syndrome, ventricular fibrillation (VF) occurs mainly during sleep, and Brugada ECG signs are intensified by parasympathomimetic drugs; therefore, vagal activity could be a precipitating factor of VF. The aim of the present study was to elucidate the relation between spontaneous augmentation of ST elevation and changes in autonomic nervous activities in the daily life of patients with Brugada syndrome. METHODS AND RESULTS: Twenty-three consecutive patients with Brugada syndrome were studied. Group VF(+) consisted of 7 symptomatic patients and 3 asymptomatic patients with inducible VF; group VF(-) consisted of 13 asymptomatic patients without documented or inducible VF. Two-channel unipolar lead (V(1) and V(2)) Holter ECG was recorded. Heart rate variability was analyzed by the maximum entropy method. Spontaneous augmentation of ST elevation (>/=1.5 mm/20 min) occurred more frequently during 24 hours in group VF(+) than in group VF(-) (5.7 +/- 2.5 times vs 2.3 +/- 2.4 times, P < 0.01). ST elevation was significantly greater in group VF(+) than in group VF(-) (2.1 +/- 0.2 mm vs 1.8 +/- 0.2 mm, P < 0.05). Power of the high-frequency component (HF: 0.15-0.4 Hz) and RR interval increased progressively, and the ratio of low-frequency component (LF; 0.04- 0.15 Hz) to high-frequency component (LF/HF) gradually decreased toward the time of maximum ST elevation. During an entire day, daytime (0-5 P.M.), and nighttime (0-5 A.M.), both HF and LF/HF were not different between groups VF(+) and VF(-). CONCLUSION: In Brugada syndrome, spontaneous augmentation of ST elevation in daily life occurred along with an increase in vagal activity. ST elevation was augmented more in patients with VF than in those without VF under similar vagal tone.     

Prevalence and prognosis of subjects with Brugada-type ECG pattern in a young and middle-aged Finnish population.

AIMS: The purpose of this study was (1) to determine the prevalence of Brugada syndrome ECG abnormalities ("Brugada sign") in two Finnish populations and (2) to evaluate the natural course of subjects with the "Brugada sign". METHODS AND RESULTS: The study population consisted of 2479 healthy male Air Force applicants (age 18-30 years), and 542 healthy middle-aged subjects (age 40-60 years). All subjects underwent a thorough physical examination and 12-lead ECG in 1980-1990 (first population) and in 1991-1992 (second population). The ECG criteria suggested by the European Society of Cardiology were used to identify subjects with the "Brugada sign". Fifteen (0.61%) subjects in the first population and three subjects in the second population (0.55%) fulfilled the ECG criteria for type 2 or 3 Brugada syndrome, i.e., they had J-point elevation and a saddleback-type ST-segment configuration in the right precordial leads. Type 1 Brugada ECG abnormality (coved ST-segment elevation) was not seen in any subject. No mortality or life-threatening ventricular arrhythmias occurred in either study population during follow-up (19+/-2 years and 11+/-1 years, respectively). CONCLUSION: The benign natural course of the patients with the "Brugada sign" suggests that in asymptomatic subjects without a family history of sudden cardiac death, type 2 or 3 Brugada ECG pattern is a normal variant rather than a specific predictor of life-threatening ventricular arrhythmias.     

发热诱发Brugada波的遗传学及心电参数危险因素分析

目的对发热诱发Brugada波的遗传学及心电参数危险性进行分析。方法使用DNA直接测序法对临床收集的5例发热诱发Brugada波患者进行基因筛查,并回顾性调查127例住院发热患者心电图上Brugada波和不完全右束支传导阻滞(IRBBB),并与正常对照组进行心电参数的比较。结果5例发热诱发Brugada ECG患者未发现基因突变。127例发热患者Brugada波1例,发生率为0.8%,13例有IRBBB。发热组患者QTc和TpTe间期较正常对照延长(P<0.05)。0.5~3年随访126例患者无一例发生心源性猝死。结论发热致Brugada波个体与钠通道基因突变无关联。发热诱发Brugada波的健康个体心血管事件发生率低。     

New electrocardiographic leads and the procainamide test for the detection of the Brugada sign in sudden unexplained death syndrome survivors and their relatives.

AIMS: Sudden unexplained death syndrome occurs in previously healthy South-east Asian young adults without any structural cause of death. The common electrocardiographic (ECG) change in sudden unexplained death syndrome survivors is right bundle branch block and ST elevations in leads V(1) to V(3), which are similar to the ECG pattern in the Brugada syndrome (Brugada sign). It is difficult to diagnose the Brugada sign with the 12-lead ECG in sudden unexplained death syndrome survivors and their family members because the ECG could be transiently normalized. We proposed using the higher intercostal space V(1) to V(3) lead ECG, together with procainamide to detect the Brugada sign. METHODS AND RESULTS: Among 20 ventricular fibrillation cardiac arrest patients, 13 sudden unexplained death syndrome survivors and their relatives (n=88) were studied using the single standard 12-lead ECG and the new six higher intercostal space V(1) to V(3) lead ECG (-V(1) to -V(3) and -2V(1) to -2V(3)). Ten sudden unexplained death syndrome survivors and relatives (n=48) who had a normalized ECG were also infused with procainamide (10 mg x kg(-1)i.v.) to unmask the Brugada sign and both ECG methods were recorded. Forty healthy individuals and 13 spouses served as the control group. Prior to the procainamide infusion, the Brugada sign could be detected in nine sudden unexplained death syndrome survivors (69.2%) and three (3.4%) relatives with the standard ECG and in 12 (92.3%) and nine (10.2%) with the new six-lead ECG. After the procainamide infusion, the Brugada sign could be demonstrated in seven sudden unexplained death syndrome survivors (70%) and seven (14.6%) relatives with the standard ECG and in nine (90%) (P=0.26) and 23 (47.9%) (P=0.0004) with the new six-lead ECG, respectively. All the controls were negative for the Brugada sign. CONCLUSIONS: Our data suggest that the new higher intercostal space lead ECG, with or without the procainamide test is helpful in detecting the Brugada sign in sudden unexplained death syndrome survivors and their relatives.