Decreased nocturnal standard deviation of averaged NN intervals. An independent marker to identify patients at risk in the Brugada Syndrome.
OBJECTIVE
Risk-stratification of asymptomatic Brugada Syndrome (BS) patients remains a key-issue. A typical spontaneous BS-ECG pattern and ventricular tachycardia (VT)/ventricular fibrillation (VF) inducibility are two recognized risk markers. The aim of the study was to identify additional risk markers in asymptomatic BS.


RESULTS
We have compared Holter recordings in symptomatic and in asymptomatic patients with BS. Heart rate variability (HRV), QT-interval rate-dependence and ST-segment elevation (ST-SE) were analysed. The study population included 47 BS patients (M=36, mean age=45+/-13 years) with a malignant ventricular arrhythmia in 11 cases, an unexplained syncope in 10 cases and no symptoms in the remaining 26 cases. A typical spontaneous BS-ECG was present in 21 cases and a drug-induced BS-ECG in 26 cases. A downward trend of the time domain variables of HRV was observed. During the nocturnal period, standard deviation (SD) of the 5min averaged NN intervals (SDANN) (46+/-13 vs 57+/-18ms, P=0.02) and ultra low frequency component (3287+/-2312 vs 5030+/-3270 ms(2), P=0.04) were significantly lower in symptomatic versus asymptomatic patients. In contrast, no difference was found in QT-interval rate dependence and in ST-SE. At multivariate logistic regression, VT/VF inducibility, typical spontaneous BS-ECG and a decreased nocturnal SDANN were associated with arrhythmic events (P=0.003).


CONCLUSIONS
A decreased nocturnal SDANN was an independent marker of arrhythmic events in these BS patients.
Hermida
Jean-Sylvain
JS
Centre Hospitalier Universitaire, Amiens, France. hermida.jean-sylvain@chu-amiens.fr
Leenhardt
Antoine
A
Cauchemez
Bruno
B
Denjoy
Isabelle
I
Jarry
Geneviève
G
Mizon
Fréderique
F
Milliez
Paul
P
Rey
Jean-Luc
JL
Beaufils
Philippe
P
Coumel
Philippe
P
D000328:Adult; D002037:Bundle-Branch Block / Q000175:diagnosis* / Q000503:physiopathology; D002940:Circadian Rhythm; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D015716:Electrocardiography, Ambulatory / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012815:Signal Processing, Computer-Assisted; D013577:Syndrome; D014693:Ventricular Fibrillation / Q000175:diagnosis