Conduction properties of the crista terminalis in patients with atrial flutter due to amiodarone therapy for atrial fibrillation.
Some patients with atrial fibrillation (AF) treated by antiarrhythmic drugs (AAD) can develop typical atrial flutter, but the mechanism is not clear. This study included 21 patients with AF. Group I (n = 7) had typical atrial flutter due to amiodarone therapy. Group II (n = 7) did not develop atrial flutter after amiodarone treatment. Group III (n = 7) did not receive AAD treatment. A 7 Fr, 20-pole electrode catheter was placed along the CT identified by fluoroscopy and intracardiac echocardiography. After restoration of the sinus rhythm, decremental pacing near the CT was performed until 2 to 1 atrial capture. Complete transverse conduction block was defined as the appearance of double potentials with opposite activation sequence along the CT. Focal transverse conduction delay was defined as the appearance of double potentials at > or = 2 recording sites. Focal transverse conduction delay was observed during pacing at the cycle length of 693 +/- 110 ms in group I, 360 +/- 97 ms in group II and 343 +/- 109 ms in group III (P = 0.001). Complete transverse conduction block was observed during pacing at the cycle length of 391 +/- 118 ms in group I and 231 +/- 23 ms in group II (P = 0.001), but not in group III. In conclusion, focal transverse conduction delay in the CT was common in patients with AF. A predisposition to the line of the conduction block in the CT might contribute to the conversion of AF to typical atrial flutter due to amiodarone therapy.
Tai
Ching-Tai
CT
Division of Cardiology, Department of Medicine, National Yang-Ming University School of Medicine, Taipei Veterans General Hospital, Taiwan, Republic of China. cttai@vghtpe.gov.tw
Lin
Yung-Kuo
YK
Lan
Fei-Chiun
FC
Chen
Hung-Yi
HY
Ding
Yu-An
YA
Chang
Mau-Song
MS
Chen
Shih-Ann
SA
D000368:Aged; D000638:Amiodarone / Q000009:adverse effects*; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects*; D001281:Atrial Fibrillation / Q000188:drug therapy; D001282:Atrial Flutter / Q000139:chemically induced* / Q000503:physiopathology*; D004594:Electrophysiology; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged
D000889:Anti-Arrhythmia Agents; D000638:Amiodarone