Transient proarrhythmic state following atrioventricular junctional radiofrequency ablation.
This study was designed to prospectively assess ventricular de- and repolarization by the QRS, QT, and JT intervals, and their dispersion in the 12-lead ECG during right ventricular pacing at 60, 70, and 80 beats/min during the first month after AV junctional RF ablation. Previous reports have found early polymorphic ventricular arrhythmia after RF AV junctional ablation. Our hypothesis was that there is a proarrhythmic state following this procedure, which depends on the paced rate and time after ablation. The analysis of the immediate changes was based on 17 patients (10 men) with a mean age of 64 years (SD 14) (range 38-82 years). A 12-lead ECG was recorded during right ventricular pacing at 60, 70, and 80 beats/min within 24 hours (day 1), between 24 and 48 hours (day 2), and 1 week after ablation (day 7). For analysis of changes beyond 1 week, 13 additional patients with a mean age of 73 years (SD 8) (range 62-90 years) were analyzed on days 1, 7, and 30. All intervals were measured with a digitizing table. The mean QRS duration shortened by 2.4% at 60 beats/min (P <0.01), and the mean QT and JT intervals shortened by 5-7% between days 1 and 7 (P < 0.001). The mean QT was 9% shorter and the mean JT interval was 13% shorter at 80 compared to 60 beats/min on day 1 (P < 0.001). QT dispersion was reduced by 13% when the stimulation rate was increasedfrom 60 to 80 beats/min on day 1 (P < 0.05). There were no significant changes beyond the first week. The study results point to the induction of a proarrhythmic state immediately after AV junctional RF ablation resolving during the first week. Repolarization shortened gradually between 80 and 60 beats/min to an extent that is suggestive of a clinically important antiarrhythmic effect at the higher rate, which was supported also by clinical experience.
Nowinski
Karolina
K
Department of Cardiology, Karolinska Institutet at Karolinska Hospital, Stockholm, Sweden. karolina.nowinski@medks.ki.se
Gadler
Fredrik
F
Jensen-Urstad
Mats
M
Bergfeldt
Lennart
L
D000200:Action Potentials; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000209:etiology*; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000601:surgery*; D001283:Atrioventricular Node / Q000601:surgery*; D006328:Cardiac Catheterization; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation / Q000009:adverse effects* / Q000379:methods; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016277:Ventricular Function, Left