UNIQUE INSIGHTS IN THE ELECTROCARDIOLOGY OF SELF-TERMINATING VENTRICULAR FIBRILLATION USING BRUGADA SYNDROME AS A MODEL
Introduction: Non-sustained ventricular fibrillation (NS-FV) can be seen in patients with Brugada Syndrome:spontaneously, during defibrillation threshold testing or during programmed ventricular stimulation. Differentiating NS-VF from sustained ventricular fibrillation (S-VF) can be important in order to avoid unnecessary electrical shocks.
Methods: Twelve-lead ECG was studied in 5 patients with Brugada Syndrome and NS-VF (group 1). Brugada pattern was demonstrated spontaneously or afterpharmacological testingwith either ajmaline or flecainide. VF was induced during electrophysiological study.For each patient in group 1, two patients with S-VF were associated (group 2), in order to compare the 2 types of arrhythmia.. Cycle length and amplitude of the fibrillatory waves were compared between 2 groups.
Results: Cycle length was longer in the NS-VF group (196,7 +/- 25,2ms) compared with S-VF group (140,7 +/- 16,8 ms), p<0,001 measured in the last 5 seconds of the arrhythmia. Amplitude of the fibrillatory waves was higher in the NS-VF group (1,17 +/- 0,47mV) compared with de S-VF group (0,3 +/-0,12 mV) p=0,002 measured in the last 5 seconds of the arrhythmia.These features can be used to differentiate the 2 types of arrhythmia in order to avoid unnecessary electrical shocks.
Conclusions: Cycle length was longer in the NS-VF group compared with S-VF group, measured in the last 5 seconds of the arrhythmia. Amplitude of the fibrillatory waves was higher in the NS-VF group compared with the S-VF group. When arrhythmia becomesunorganized, with rapid, low amplitude fibrillatory waves, electrical shock should be administrated.