Macroreentrant biatrial tachycardia relevant to interatrial septal incisions after mitral valve surgery: Electrophysiological characteristics and ablation strategy

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.