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

Abstract

Background Ablation of atrial tachycardia (AT) that occurs after cardiac surgery or prior ablation often requires complex lesion sets. In combination with the pre‐existing atrial scar, these lesion sets may result in inadvertent intra‐atrial conduction block. This study reports the phenomenon of incidental isolation of right atrial (RA) regions that occurs secondary to AT ablation, which in some cases results in profound bradycardia due to sinus exit block. Methods and Results Intracardiac electrograms were examined in consecutive patients who underwent AT ablation in the RA. Cases of localized isolation of the RA were defined as areas that developed electrical dissociation during ablation. Of 132 patients having ablation in both the RA free wall and the cavotricuspid isthmus (CTI), 10 (7.6%) developed unintentional isolation of the lateral RA. Five of these patients had prior mitral valve surgery, comprising 12.2% of all 41 patients with mitral surgery who underwent ablation in the CTI and the RA free wall. All patients with regional isolation had a pre‐existing scar in the lateral wall of the RA. In six patients, isolation of the lateral RA resulted in profound bradycardia due to exit block from the peri‐sinus node myocardium. Conclusions Complex ablation lesions in patients with prior valve surgery, prior ablation, or atrial myopathy may result in unintended localized conduction block in the RA. In some cases, isolation of the lateral RA can result in complete sinus exit block with profound bradycardia requiring pacemaker implantation.

Catheter ablation of atrial tachycardias after mitral valve surgery: A systematic review and meta‐analysis

“…Year of publication ranged from 2002 to 2019 (seven [14][15][16][17][18][19][20] in the last 5 years). The studies were from different geographic areas with nine (64%) from western countries (four in Europe, four in the USA, and one in Australia).…”

“…Of note, demographic characteristics (including age and sex) were available in 218 patients (96%). [14][15][16][17][18][19][20][22][23][24][25][26][27] Left ventricular ejection fraction (LVEF) was available in 183 patients (81%) from eight studies (57%) [14][15][16][17][18]22,23,27 and left atrial anteroposterior diameter was available in 156 patients (69%). [15][16][17][18][19]22,23,26,27 All patients underwent MVS; however, the type of MVS was not clearly reported in three studies (21%).…”

“…[15][16][17][18][19]22,23,26,27 All patients underwent MVS; however, the type of MVS was not clearly reported in three studies (21%). 14,20,21 Briefly, 67% and 33% of patients underwent MV replacements with biological or mechanical prostheses and mitral valvuloplasty, respectively. Surgical ablation for AF was performed in 129 patients (59%) as either Cox-Maze IV procedure (94%), using different energy sources, or epicardial pulmonary vein isolation (6%).…”

“…ATs suppression was obtained in 212 patients leading to an overall pooled estimate of acute procedural success equal to 95% (95% CI: 87 to 100, p < .0001; I 2 = 53%, p = .010) ( Figure 2). Subgroup analysis revealed a significant improvement in the procedural success (heterogeneity between subgroups: p = .027) among the 10 studies [14][15][16][17][18][19][20][22][23][24] published after the year 2010 (pooled estimate of the proportion of 97%; 95% CI: 92%-100%; I 2 = 39.7%; p = .09) when compared to the four studies 21,[25][26][27] published before 2010 (pooled estimate of proportion 81%; 95% CI: 56%-98%; I 2 = 17%; p = .31). The formal test for publication bias did not achieve statistical significance (p = .071).…”

Atrial Cardiomyopathy: An Unexplored Limb of Virchow's Triad for AF Stroke Prophylaxis

“…While the distribution of LA fibrosis is variable among AF patients, the anterior LA is especially pronounced and vulnerable to both fibrosis and focal drivers of AF. In patients with complex atrial anatomy, such as patients with prior valve surgery, history of atrial ablation procedures, and fibrotic AC, complex ablation lesions may result in lateral RA isolation or even complete sinus exit block with bradycardia requiring pacemaker implantation (83). Regarding recurrence of arrhythmias, atrial fibrosis is an independent risk factor for AF recurrence after pulmonary vein isolation without LA substrate modification (84).…”