Class IC antiarrhythmic drug induced atrial flutter: electrocardiographic and electrophysiological findings and their importance for long term outcome after right atrial isthmus ablation.
OBJECTIVE
To describe the electrocardiographic and electrophysiological findings of new atrial flutter developing in patients taking class IC antiarrhythmic drugs for recurrent atrial fibrillation, and to report the long term results of right atrial isthmus ablation in relation to the ECG pattern of spontaneous atrial flutter.


METHODS
Retrospective analysis.


METHODS
Tertiary care academic hospital.


METHODS
24 consecutive patients with atrial fibrillation (age 54 (12) years; 5 female, 19 male) developing atrial flutter while taking propafenone (n = 12) or flecainide (n = 12).


RESULTS
The ECG was classified as typical (n = 13; 54%) or atypical atrial flutter (n = 8) or coarse atrial fibrillation (n = 3). Counterclockwise atrial flutter was the predominant arrhythmia. Acute success after isthmus ablation was similar in patients with typical (12/13) and atypical (8/8) atrial flutter. After long term follow up (13 (6) months, range 6-26 months), continuation of antiarrhythmic drug treatment appeared to result in better control of recurrences of atrial fibrillation in patients with typical atrial flutter (11/13) than in those with atypical atrial flutter (4/8), but the difference was not significant. Ablation for coarse atrial fibrillation was unsuccessful.


CONCLUSIONS
New atrial flutter developing in patients taking class IC antiarrhythmic drugs for recurrent atrial fibrillation has either typical or atypical flutter wave morphology on ECG. The endocardial activation pattern and the acute results of ablation suggest that the flutter circuit was located in the right atrium and that the isthmus was involved in the re-entry mechanism. There appeared to be better long term control of recurrent atrial fibrillation in patients with typical (85%) as compared with atypical atrial flutter (50%). Patients developing coarse atrial fibrillation may not be candidates for this strategy.
Department of Cardiology, Academic Hospital Maastricht, Cardiovascular Research Institute Maastricht, P Debyelaan 25, 6202 AZ, Postbox 5800, Maastricht, Netherlands.
A
A
Nabar
L M
LM
Rodriguez
C
C
Timmermans
R
R
van Mechelen
H J
HJ
Wellens
D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects*; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000601:surgery; D001282:Atrial Flutter / Q000139:chemically induced* / Q000175:diagnosis / Q000601:surgery*; D017115:Catheter Ablation; D004562:Electrocardiography; D005260:Female; D005424:Flecainide / Q000009:adverse effects; D006325:Heart Atria; D006801:Humans; D008297:Male; D008875:Middle Aged; D011405:Propafenone / Q000009:adverse effects*; D012189:Retrospective Studies
D000889:Anti-Arrhythmia Agents; D011405:Propafenone; D005424:Flecainide