ClinicalGeneticClinical impact of the number of extrastimuli in programmed electrical stimulation in patients with Brugada type 1 electrocardiogram
Introduction
Brugada syndrome (BrS) is a channelopathy that can cause sudden death due to ventricular fibrillation (VF) in apparently healthy individuals in their prime. Since Brugada et al reported it first in 1992, several indices have been reported as reliable prognostic factors.1, 2, 3, 4, 5, 6 However, there remains much room for debate in prognostic indices except for history of VF.7 Although induction of lethal ventricular arrhythmia (VA) by programmed electrical stimulation (PES) is still widely adopted for deciding the indication of an implantable cardioverter-defibrillator (ICD), controversial data have been reported regarding its prognostic value.2, 4, 7, 8, 9 Brugada et al reported that VF inducibility by PES can be a strong predictor of subsequent cardiac events in patients with BrS.8 However, other studies could not confirm these findings.2, 4, 7 Because protocols of PES and backgrounds of patients were different in each study, direct comparison of the results was not possible. Moreover, clinical significance of the number of extrastimuli, the site of induction, and the coupling interval of extrastimuli at the time of VF induction by consistent protocol have not been fully elucidated.
The aim of the present study was to test the hypothesis that subsequent cardiac events occur more frequently in patients with BrS with induction of VAs by fewer extrastimuli during PES. Thus, we examined the relationships of several parameters of PES, especially the number of extrastimuli, the site of induction, and the coupling interval of extrastimuli at the time of VF induction, with subsequent cardiac events.
Section snippets
Study population
The study population consisted of consecutive 108 Japanese patients with Brugada type 1 electrocardiogram (ECG) in the absence or presence of sodium-channel–blocking agent (104 men, mean age 46 ± 12 years) who underwent electrophysiological study at National Cerebral and Cardiovascular Center, Suita, Japan, between 1993 and 2009. Twenty-six patients had a history of VF, 40 had a history of syncope, and 42 were asymptomatic at the time of the electrophysiological study. Patients' characteristics
Electrophysiological study
VA was induced in 81 patients (VF in 71 and PVT in 10): in 4 by single extrastimulus, in 41 by double extrastimuli, and in 36 by triple extrastimuli. There were 45 patients in group SD, 36 in group T, and 27 in group N.
Patients' characteristics are presented in Table 2. There were no significant differences among the 3 groups in gender, age, history of VF or syncope, family history of BrS or sudden death under 45 years of age, and age at the first cardiac event. There were also no significant
Conclusion
The number of extrastimuli in PES that induced ventricular arrhythmias served as a prognostic indicator for patients with type 1 Brugada ECG. The site of induction and the coupling interval of extrastimuli at the time of VF induction were not prognostic indicators of patients with BrS. Our data suggest that PES in patients with type 1 Brugada ECG should employ up to 2 extrastimuli, rather than 3.
References (24)
- et al.
Right bundle branch block, persistent ST segment elevation and sudden cardiac death: a distinct clinical and electrocardiographic syndrome: a multicenter report
J Am Coll Cardiol
(1992) - et al.
Augmented ST-segment elevation during recovery from exercise predicts cardiac events in patients with Brugada syndrome
J Am Coll Cardiol
(2010) - et al.
Electrophysiologic characteristics and implications of induced ventricular fibrillation in symptomatic patients with Brugada syndrome
J Am Coll Cardiol
(2002) - et al.
Genotype–phenotype relationship in Brugada syndrome: electrocardiographic features differentiate SCN5A-related patients from non-SCN5A-related patients
J Am Coll Cardiol
(2002) - et al.
Comparison of long-term follow-up of electrocardiographic features in Brugada syndrome between the SCN5A-positive probands and the SCN5A-negative probands
Am J Cardiol
(2007) - et al.
Cellular basis for trigger and maintenance of ventricular fibrillation in the Brugada syndrome model: high-resolution optical mapping study
J Am Coll Cardiol
(2006) - et al.
An international compendium of mutations in the SCN5A-encoded cardiac sodium channel in patients referred for Brugada syndrome genetic testing
Heart Rhythm
(2010) - et al.
Long-term prognosis of probands with Brugada-pattern ST-elevation in leads V1–V3
Circ Arrhythm Electrophysiol
(2009) - et al.
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
Circulation
(2002) - et al.
Natural history of Brugada syndrome: insights for risk stratification and management
Circulation
(2002)
Noninvasive risk stratification of subjects with a Brugada-type electrocardiogram and no history of cardiac arrest
Ann Noninvasive Electrocardiol
Long-term prognosis of patients diagnosed with Brugada syndrome: results from the FINGER Brugada syndrome registry
Circulation
Cited by (0)
This work was supported by a research grant for the cardiovascular diseases (grant number H23-114, 22-1-2) from the Ministry of Health, Labor, and Welfare, Japan, and a grant from Japan Cardiovascular Research Foundation. Dr Shimizu was supported in part by a research grant for the cardiovascular diseases (grant number 21C-8, 22-4-7) from the Ministry of Health, Labor, and Welfare, Japan, and a Grant-in-Aid for Scientific Research on Innovative Areas (grant number 22136011).