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


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).


CONCLUSIONS
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.
Ajiro
Youichi
Y
The Heart Institute of Japan, Tokyo Women's Medical University, Tokyo, Japan.
Hagiwara
Nobuhisa
N
Kasanuki
Hiroshi
H
D015415:Biomarkers; D002037:Bundle-Branch Block / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality*; D018572:Disease-Free Survival; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D062554:NAV1.5 Voltage-Gated Sodium Channel; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D055502:Secondary Prevention; D012720:Severity of Illness Index; D015222:Sodium Channels / Q000235:genetics; D016019:Survival Analysis; D013577:Syndrome; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000401:mortality*
D015415:Biomarkers; D062554:NAV1.5 Voltage-Gated Sodium Channel; C568320:SCN5A protein, human; D015222:Sodium Channels