Background: Macroreentrant biatrial tachycardia (BiAT) associated with interatrial septal incisions after mitral valve (MV) surgery has been rarely reported.
Objective: The purpose of this study was to assess the mapping and ablation strategy of this special category of atrial tachycardia (AT).
Methods: We identified 10 BiATs from a total of 84 ATs after MV surgery performed at 3 institutions. Activation maps for both the right atrium (RA) and left atrium (LA) were obtained using an ultrahigh-density mapping system. We also performed entrainment pacing from multiple LA and RA site within the speculative circuit.
Results: By analyzing activation and propagation maps of both atria, we classified the circuit into 3 distinct types. In all types, posteroinferior interatrial connections act as a critical limb that, combined with other interatrial connections (Bachmann bundle, fossa ovalis, and coronary sinus ostium in 3 types, respectively), complete the circuit of BiATs. Most ATs (8/10) were terminated targeting the RA and LA end of posteroinferior interatrial connection sites.
Conclusion: Ultrahigh-density mapping provides a detailed description of the macroreentrant circuit of BiAT associated with interatrial septal incisions. Posteroinferior interatrial connections were essential for the circuit and should be the preferred target for ablation.
Keywords: Ablation; Atrial tachycardia; High-density mapping; Interatrial septum; Reentrant tachycardia.
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