Key result
Mitral isthmus ablation terminates biatrial tachycardia, maintaining 4-month freedom from antiarrhythmic drugs and symptoms.
Why the study?
Does catheter ablation of the mitral isthmus treat biatrial tachycardia while preserving left atrial appendage activation in a patient with extensive prior ablations?
Case Report (n=1)
No
Does catheter ablation of the mitral isthmus treat biatrial tachycardia while preserving left atrial appendage activation in a patient with extensive prior ablations?
Targeting the mitral isthmus rather than Bachmann's bundle can successfully treat biatrial tachycardia while avoiding electrical isolation of the left atrial appendage in patients with extensive prior ablations.
May support mitral isthmus ablation in select post-ablation biatrial tachycardia; hypothesis-generating and should not yet change practice.
A 57-year-old man underwent his seventh ablation session for atrial tachycardia (AT). His previous ablations involved several regions of the right atrium (RA) and left atrium (LA). The AT was characterized as biatrial tachycardia with a circuit involving the mitral annulus and septal RA. The AT was terminated by ablation through the insertion site of Bachmann's bundle (BB) in both atria. After 3 months, the patient underwent his eighth ablation session because of AT recurrence. Activation maps showed that the connection from the RA to LA and vice versa was maintained via BB and the coronary sinus, respectively. The ablation target to interrupt the AT circuit was the mitral isthmus (MI), not BB, because BB supplied the electrical activation of the left atrial appendage (LAA) via a unidirectional electrical connection from the RA to LA. Ablation attempts from within the coronary sinus were performed to target the epicardial connection in the MI and led to complete blockage of the connection from the LA to RA. Otherwise, the connection from the RA to LA was preserved via BB. The patient was free of symptoms and anti-arrhythmic drugs at the 4-month follow-up. However, he had a high risk of electrical isolation of the LAA because extensive ablations had been performed; the strategy of targeting the MI contributed to the balance between preserving the electrical activation of the LAA and treating the biatrial tachycardia. Verification of the connective pathway between the two atria might be helpful to determine the optimal target.
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Ishiguchi et al. (2020) conducted a case report in Biatrial tachycardia (n=1). Catheter ablation of the mitral isthmus was evaluated on Freedom from symptoms and anti-arrhythmic drugs. Ablation of the mitral isthmus successfully terminated biatrial tachycardia and maintained freedom from symptoms and anti-arrhythmic drugs at 4 months while preserving left atrial appendage activation.
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