A Novel Criterion for Conduction Block After Catheter Ablation of Right Atrial Tachycardia After Mitral Valve Surgery

Abstract

Background— One operative approach to the mitral valve, the superior transseptal incision, is proarrhythmic because of extensive atriotomies. The objective of this study is to describe complex atrial tachycardias (ATs) that occur after this approach and propose methods to verify lines of block as an end point for catheter ablation. Methods and Results— Of the 69 patients who had electrophysiological studies for AT after mitral valve surgery, 20 patients had prior superior transseptal incisions. Of these, 14 had complex ATs involving the lateral right atrium (RA). There were 9 dual-loop, 4 single-loop, and 1 focal tachycardias. Lateral wall ablation was performed either by creating a linear lesion from the lateral atriotomy to the inferior vena cava, superior vena cava, or tricuspid annulus or by ablating focally in the lateral RA. After a single ablation procedure, conduction block in the lateral wall was verified in 10 of 14 patients using 1 of 2 distinct patterns of block. One pattern consisted of late activation in an anterolateral corridor of the RA, and a second pattern consisted of wide-spaced double potentials. Recurrent conduction through the lateral wall lesions was associated with intraprocedural and late recurrences of ATs. Conclusions— The optimal end point for ablating ATs after mitral valve surgery with the superior transseptal approach is to establish lines of block that can be recognized by characteristic patterns of activation in the lateral RA. A novel criterion for lateral conduction block after catheter ablation is identification of a late-activated corridor in the anterolateral RA.

Regional isolation in the right atrium with disruption of intra‐atrial conduction after catheter ablation of atrial tachycardia

“…9 The superior transseptal approach, in particular, is arrhythmogenic and also can interfere with sinus node function. [10][11][12] In fact, for mitral valve surgery patients having ablation in both the CTI and the RA free wall, the rate of regional RA block was 12%. These findings indicate that atypical flutters arising from the RA in patients with prior mitral surgery are often associated with extensive conduction abnormalities and ablation of these arrhythmias poses a substantial risk of bradycardia.…”

“…These approaches involve right atriotomies in addition to septal incisions and create substrates for reentrant ATs . The superior transseptal approach, in particular, is arrhythmogenic and also can interfere with sinus node function . In fact, for mitral valve surgery patients having ablation in both the CTI and the RA free wall, the rate of regional RA block was 12%.…”

Successful Treatment of Macroreentrant Atrial Tachycardia by Radiofrequency Ablation Targeting Channels with Continuous Activation

“…In addition, to establish lines of blockade in double‐loop right atrial MRAT, most strategies start from a single linear ablation at either of these two loops, such as the cavotricuspid isthmus. Such strategies require a second ablation procedure to eliminate the other reentrant loop . Because the atrial catheters for activation references might be located in the second loop, there would be a misinterpretation if no significant changes were observed in surface ECG and electrograms during ablation of the first reentrant loop.…”

Abnormal atrial strain with speckle-tracking echocardiography predicts the arrhythmic substrate of atypical right atrial flutter

“…Atypical RA flutter was observed in patients who had undergone prior cardiac surgery for obvious structural heart disease 2, 3, 4. In recent years, a few reports have described atypical RA flutter in patients without obvious structural heart disease or previous cardiac surgery 5, 6, 7.…”