Key result
The presence of a local coronary artery across the mitral isthmus was associated with a significantly lower rate of successful bidirectional block compared to its absence (42% vs 92%; P<0.001).
Why the study?
Does the presence of a local coronary artery across the mitral isthmus prevent the successful creation of a bidirectional block line in patients with atrial fibrillation?
Observational (n=81)
Does the presence of a local coronary artery across the mitral isthmus prevent the successful creation of a bidirectional block line in patients with atrial fibrillation?
Absolute Event Rate: 42% vs 92%
p-value: p=<0.001
The presence of a local coronary artery at the mitral isthmus and a larger coronary sinus diameter are independent risk factors for failing to achieve a complete mitral isthmus block line during AF ablation.
May warrant pre-procedural coronary imaging before mitral isthmus ablation in AF; leaves open whether anatomy modifies block success in prospective trials.
BACKGROUND: The addition of a mitral isthmus (MI) block line after pulmonary vein isolation could lead to a favorable outcome of catheter ablation in patients with atrial fibrillation (AF). However, it is sometimes tough to create a complete MI block line, and the cooling effect because of the local coronary flow may prevent the creation of a successful MI block line. METHODS AND RESULTS: This study enrolled 81 AF patients in whom the creation of an MI block line was attempted in those with persistent or pacing-inducible AF after pulmonary vein isolation. A local coronary artery (LCA) across the MI block line was observed in 43 (53%) of 81 patients, and a bidirectional MI block was successfully accomplished in 53 (65%) of 81 patients, at the estimated MI line. The ratio of a successful MI block line was significantly lower in the patients with an LCA than in those without an LCA (42% versus 92%; P<0.001). The mean diameter of the coronary sinus (0.59 ± 0.18 versus 0.82 ± 0.22 cm; P<0.001) and length of the estimated MI line (33.4 ± 9.9 versus 29.4 ± 7.1 mm; P=0.032) were significantly shorter in the patients with a successful MI block line than in those without a successful MI block line. In the multivariable analysis, an LCA at the MI and a larger coronary sinus diameter were independent risk factors for an unsuccessful MI block line. CONCLUSIONS: Local coronary flow at the MI is associated with an increased incidence of an unsuccessful MI block line.
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Kurotobi et al. (2011) conducted an observational in Atrial fibrillation (n=81). Presence of a local coronary artery across the mitral isthmus block line vs. Absence of a local coronary artery was evaluated on Successful bidirectional mitral isthmus block line (p=<0.001). The presence of a local coronary artery across the mitral isthmus was associated with a significantly lower rate of successful bidirectional block compared to its absence (42% vs 92%; P<0.001).
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