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.

Pattern of inheritance in three sudden unexplained death syndrome ("Lai-tai") families.

Sudden Unexplained Death Syndrome (SUDS) (or Lai-tai) is sudden death in previously healthy young adults without any structural cause of death from autopsy findings. Our previous data showed that familial SUDS is not X-linked recessive. The objective of this study was to determine the pattern of inheritance in familial SUDS using the ECG markers of Brugada syndrome (RBBB and ST-segment elevation in V1 to V3), SUDS and presumptive SUDS as phenotypes. We employed the standard 12-lead ECG and higher intercostal space (ICS) V1 to V3 (-V1 to -V3 and -2V1 to -2V3) leads ECG in SUDS relatives after procainamide and drew the pedigree. We studied 62 relatives of 9 SUDS victims who died in Singapore and selected 3 families (n = 34) for the procainamide test and ECG. The mean age was 36.4 +/- 23.6 years (4-78 years). Three SUDS families showed the same pattern of inheritance of autosomal dominant.

Right ventricular electrocardiographic leads for detection of Brugada syndrome in sudden unexplained death syndrome survivors and their relatives.

BACKGROUND: Sudden unexplained death syndrome (SUDS) is a sudden death syndrome in previously healthy Southeast Asian young adults without any structural causes of death. Many SUDS survivors show electrocardiographic (ECG) evidence of RSR' and ST elevation in leads V1 to V3, which is similar to the ECG pattern in Brugada syndrome. However, in many cases transient normalization of the ECG does not make diagnosis with standard 12-lead ECG possible. HYPOTHESIS: To overcome this problem, we utilized the new right ventricular ECG leads to detect the Brugada syndrome in SUDS survivors. METHODS: The subject was a Thai male patient who presented with a SUDS-like syncopal attack. He had cardiac arrest due to idiopathic ventricular fibrillation. RESULTS: Post-resuscitation standard 12-lead ECG showed no diagnostic features of Brugada syndrome. However, ECG patterns of RSR' and ST elevations typical for Brugada syndrome could be detected at the higher intercostal space leads V1 to V3. We observed similar findings in 2 of the other 10 SUDS survivors and 4 of 23 healthy family members. CONCLUSIONS: Our data suggest that these new right ventricular leads ECG may be helpful in detecting Brugada syndrome in SUDS survivors and their relatives.