Macro-reentrant atrial tachycardia after tricuspid or mitral valve surgery: is there difference in electrophysiological characteristics and effectiveness of catheter ablation?

Fig. 1. Right atrial MAT ablation. In A the flutter wave of counterclockwise CTI-dependent AFL was negative in inferior limb leads (II, III and aVF), positive in precordial lead V1, and progressively became shallow negative from precordial lead V2 to V6. In B the flutter wave of clockwise CTI-dependent AFL was positive in inferior limb leads, negative in precordial lead V1, and progressively became positive in precordial lead V2 to V6. In C counterclockwise AFL was terminated by CTI linear ablation after tricuspid valve bio-prosthesis implantation. Of note, two pouches were found in proximity to the tricuspid annulus (TA) and at the mid-portion of the CTI area (white arrows). Extensive and prolonged RF energy delivery was needed to interrupt AFL and achieve CTI block. The dotted circle represented the tricuspid annulus (TA). In D right atriotomy-related macro-reentry was identified to around the scar line (gray dots line), entrainment pacing at either side of the scar line produced a matched PPI. The critical isthmus was found between the inferior border of the scar and the inferior vena cava, where short linear RF ablation terminated the tachycardia and rendered it non-inducible. Of…

Fig. 2. “Figure-of-eight” right atrial MAT ablation after mitral valve prosthesis replacement. A–J showed the activation sequence of the “figure-of-eight” macro-reentry using a common isthmus, which was localized in a low voltage area, bounded by bilateral lines of block K at the postero-lateral wall of the RA. The white solid lines represented lines of block defined by the system algorithm. White arrows indicated the activation direction from the earliest to the latest area. In L, M the MAT was terminated by a short linear ablation across the common isthmus (LL and PA view). Note the small diastolic potentials at the site of MAT termination. In N a prophylactic short line was added to prevent other possible macro-reentries. Abbreviations referred to Fig. 1