Takekuni Hayashi1, Seiji Fukamizu2, Takeshi Mitsuhashi3, Takeshi Kitamura2, Yuya Aoyama2, Rintaro Hojo2, Yoshitaka Sugawara3, Harumizu Sakurada4, Masayasu Hiraoka5, Hideo Fujita3, Shin-Ichi Momomura3. 1. Division of Cardiovascular Medicine, Saitama Medical Center, Jichi Medical University, Saitama, Japan. Electronic address: hayahsi1979@yahoo.co.jp. 2. Department of Cardiology, Tokyo Metropolitan Hiroo Hospital, Tokyo, Japan. 3. Division of Cardiovascular Medicine, Saitama Medical Center, Jichi Medical University, Saitama, Japan. 4. Department of Cardiology, Tokyo Metropolitan Health and Medical Treatment Corporation Ohkubo Hospital, Tokyo, Japan. 5. Toride Kitasohma Medical Center Hospital, Ibaraki, Japan.
Abstract
OBJECTIVES: The aim of this study was to determine whether re-entrant circuits were associated with the ligament of Marshall (LOM). BACKGROUND: Peri-mitral atrial tachycardias (PMATs) following pulmonary vein isolation (PVI) or mitral valve surgery are common. METHODS: Six PMATs involving epicardial circuits were identified from 38 patients. Of these, 4 PMATs involved the LOM (PMAT-LOM, mean cycle length 308 ± 53 ms), as confirmed by the insertion of a 2-F electrode in the vein of Marshall (VOM). All patients underwent PVI and mitral isthmus ablation. The PMAT-LOMs were diagnosed based on left atrium (LA) activation maps that covered <90% of tachycardia cycle length (TCL), and a difference between the post-pacing interval and TCL that was: 1) ≤20 ms at the VOM, the ridge between the left pulmonary vein and appendage, the anterior wall of the LA, and along the 6 to 11 o'clock direction of the mitral annulus; and 2) >20 ms at the distal coronary sinus (CS), the posterior wall of the LA, and the mitral isthmus ablation line (or noncapture). Catheter ablation was performed at the ridge for all PMAT-LOMs. RESULTS: Three tachycardias were successfully terminated at the ridge, which showed continuous fractionated potential lasting >100 ms, confirming the bidirectional block of Marshall bundle (MB)-LA connections. The remaining tachycardia required ablation for the CS-MB connections, confirming bidirectional block of CS-MB connections. CONCLUSIONS: PMAT-LOMs following PVI or valve surgery accounted for up to 11% of PMATs. The bidirectional block of either MB-LA or CS-MB connections is required to eliminate PMAT-LOMs.
OBJECTIVES: The aim of this study was to determine whether re-entrant circuits were associated with the ligament of Marshall (LOM). BACKGROUND:Peri-mitral atrial tachycardias (PMATs) following pulmonary vein isolation (PVI) or mitral valve surgery are common. METHODS: Six PMATs involving epicardial circuits were identified from 38 patients. Of these, 4 PMATs involved the LOM (PMAT-LOM, mean cycle length 308 ± 53 ms), as confirmed by the insertion of a 2-F electrode in the vein of Marshall (VOM). All patients underwent PVI and mitral isthmus ablation. The PMAT-LOMs were diagnosed based on left atrium (LA) activation maps that covered <90% of tachycardia cycle length (TCL), and a difference between the post-pacing interval and TCL that was: 1) ≤20 ms at the VOM, the ridge between the left pulmonary vein and appendage, the anterior wall of the LA, and along the 6 to 11 o'clock direction of the mitral annulus; and 2) >20 ms at the distal coronary sinus (CS), the posterior wall of the LA, and the mitral isthmus ablation line (or noncapture). Catheter ablation was performed at the ridge for all PMAT-LOMs. RESULTS: Three tachycardias were successfully terminated at the ridge, which showed continuous fractionated potential lasting >100 ms, confirming the bidirectional block of Marshall bundle (MB)-LA connections. The remaining tachycardia required ablation for the CS-MB connections, confirming bidirectional block of CS-MB connections. CONCLUSIONS: PMAT-LOMs following PVI or valve surgery accounted for up to 11% of PMATs. The bidirectional block of either MB-LA or CS-MB connections is required to eliminate PMAT-LOMs.