Role of Signal-Averaged Electrocardiograms for Predicting the Inducibility of Ventricular Fibrillation in the Syndrome Consisting of Right Bundle Branch Block and ST Segment Elevation in Leads V1-V3.

Abstract

SUMMARYRight bundle branch block and ST segment elevation (RBBB-STE) in the right precordial leads have been reported as a distinct clinical and electrocardiographic syndrome in patients prone to ventricular fibrillation (VF) in the absence of structural heart disease (Brugada syndrome). The purpose of the study was to investigate the role of signal averaged electrocardiogram (SAECG) in identifying patients at high risk among asymptomatic RBBB-STE patients. Thirteen patients with the RBBB-STE ECG were identified. Symptoms were: syncope (n=3, cases 1, 3, and 11), atypical chest pain (n=3, cases 4, 10, and 12) and palpitations (n=2, cases 6, and 7). The other 5 patients were asymptomatic. SAECG and programmed electrical stimulation (PES) were conducted in all patients. Body surface late potentials (LPs) were present in 7 of 13 patients before PES. Vf was induced in 6 of 7 LP positive patients. Vf was induced in 3 of 6 LP negative patients, but LP became positive in 2 of 3 patients in whom Vf was induced. One patient with syncope due to VF (case 1), 1 patient without symptoms who died suddenly during follow up (case 2), and 1 asymptomatic patient (case 9) showed reproducibly positive LP. In a patient (case 9) with positive LP at baseline, LP transiently became negative during follow up. In RBBB-STE patients, reproducibly positive LP is at risk for malignant ventricular arrhythmias and sudden death. Repeated SAECG recording may be useful for screening high-risk patients who should receive electrophysiological study among asymptomatic RBBB-STE patients. (

Endocardial Electrograms From the Right Ventricular Outflow Tract After Induced Ventricular Fibrillation in Patients With Brugada Syndrome

“…However, the existence of conduction delay at the RVOT has been suggested in many reports. [4][5][6][11][12][13][14] In addition, several clinical studies have suggested that spontaneous episodes of VF are triggered by premature ventricular contractions originating mainly from the RVOT. 19 However, this electrical abnormality has not been shown by endocardial mapping in a routine electrophysiologic study.…”

“…The positive LP that characterizes BS is defined at our institution as a root mean square voltage of the last 40 ms <20 V. 5 …”

“…[1][2][3] However, several studies have shown a high incidence of ventricular late potentials (LPs) [4][5][6] and a high rate of induction of ventricular fibrillation (VF) by programmed ventricular stimulation (PVS). [7][8][9][10] Furthermore, recent reports have indicated that delayed activation of the RV outflow tract (RVOT) contributes to the electrocardiographic characteristics and arrhythmogenesis of BS.…”

Atrial Electrophysiological Abnormality in Patients With Brugada Syndrome Assessed by P-Wave Signal-Averaged ECG and Programmed Atrial Stimulation

“…Positive late potential characterizing BS is defined in our institution as the root mean square voltage of the last 40 ms <20 V. 8 The P-wave signal-averaged ECG was recorded in all 15 controls by using a P-wave triggered and bidirectionally filtered mode (MAC VU ECG unit; Marquette Co, Milwaukee, WI, USA). The FPD was calculated from the vector magnitude of the X, Y, Z leads.…”

“…Arrhythmias such as premature ventricular contraction, monomorphic ventricular tachycardia, [3][4][5] polymorphic ventricular tachycardia, and ventricular fibrillation (VF) 1,2,6 and a high incidence of positive ventricular late potentials have been reported in patients with BS. [7][8][9] The discovery of associated mutations of the sodium channel gene in some patients confirmed the primary electrical nature of the disease. 10,11 If BS is a sodium channel disease, it is possible that an electrical abnormality exists not only in the ventricular myocardium but also in the atrial myocardium.…”