Long-Term Outcome Following Ablation of Atrial Tachycardias Occurring after Mitral Valve Replacement in Patients with Rheumatic Heart Disease

Outcome of tailored therapy in rheumatic heart disease with persistent atrial fibrillation (RHD-AF)

INTRODUCTION

Rheumatic heart disease with persistent atrial fibrillation (RHD-AF) is associated with increased morbidity. However, there is no standardized approach for the maintenance of sinus rhythm (SR) in them. We aimed to determine the utility of a stepwise approach to achieve SR in RHD-AF.

METHODS

Consecutive patients with RHD-AF from July 2021 to August 2023 formed the study cohort. The stepwise approach included pharmacological rhythm control and/or electrical cardioversion (Central illustration). In patients with recurrence, additional options included AF ablation or pace and ablate strategy with conduction system pacing or biventricular pacing. Clinical improvement, NT-proBNP, 6-Minute Walk Test (6MWT), heart failure (HF) hospitalizations, and thromboembolic complications were documented during follow-up.

RESULTS

Eighty-three patients with RHD-AF (mean age 56.13 ± 9.51 years, women 72.28%) were included. Utilizing this approach, 43 (51.81%) achieved and maintained SR during the study period of 11.04 ± 7.14 months. These patients had improved functional class, lower NT-proBNP, better distance covered for 6MWT, and reduced HF hospitalizations. The duration of AF was shorter in patients who achieved SR, compared to those who remained in AF (3.15 ± 1.29 vs 6.93 ± 5.23, p = 0.041). Thirty-five percent (29) maintained SR after a single cardioversion over the study period. Only one underwent AF ablation. Of the 24 who underwent pace and ablate strategy, atrial lead was implanted in 22 (hybrid approach), and 50% of these achieved and maintained SR. Among these 24, none had HF hospitalizations, but patients who maintained SR had further improvement in clinical and functional parameters.

CONCLUSIONS

RHD-AF patients who could achieve SR with a stepwise approach, had better clinical outcomes and lower HF hospitalizations.

High density mapping of complex atrial tachycardia in patients after cardiac surgery

To provide an overview of the current application of high-density mapping (HDM) in the mechanism of complex atrial tachycardias (ATs). Complex ATs are frequently scar-related, after history of previous cardiac surgery and large scars. These scar-related ATs are difficult to manage medically and frequently recur after electrical cardioversion. HDM technologies have enabled rigorous elucidation of AT mechanisms in patients post cardiac surgery. This article showed the application of HDM technology in complex ATs from the mechanisms of complex ATs, the development of HDM technology, and the identification of scars or critical isthmus from HDM. HDM-guided approach is highly effective for identifying the ATs mechanism and critical isthmus.

Long-term clinical outcome of atrial fibrillation ablation in patients with history of mitral valve surgery

Aims

Atrial fibrillation (AF) occurs frequently after mitral valve (MV) surgery. This study aims to evaluate the efficacy and long-term clinical outcomes after the first AF ablation in patients with prior MV surgery.

Methods

Sixty consecutive patients with a history of MV surgery without MAZE referred to three European centers for a first AF ablation between 2007 and 2017 (group 1) were retrospectively enrolled. They were matched (propensity score match) with 60 patients referred for AF ablation without prior MV surgery (group 2).

Results

After the index ablation, 19 patients (31.7%) from group 1 and 24 (40%) from group 2 had no recurrence of atrial arrhythmias (ATa) (p = 0.3). After 62 (48-84) months of follow-up and 2 (2-2) procedures, 90.0% of group 1 and 95.0% of group 2 patients were in sinus rhythm (p = 0.49). In group 1, 19 (31.7%) patients had mitral stenosis, and 41 (68.3%) had mitral regurgitation. Twenty-seven (45.0%) patients underwent mechanical valve replacement and 33 (55.0%) MV annuloplasty. At the final follow-up, 28 (46.7%) and 33 (55.0%) patients were off antiarrhythmic drugs (p = 0.46). ATa recurrence was seen more commonly in patients with prior MV surgery (54 vs. 22%, respectively, p < 0.05). No major complication occurred.

Conclusion

Long-term freedom of atrial arrhythmias after atrial fibrillation catheter ablation is achievable and safe in patients with a history of mitral valve surgery. In AF patients without a history of mitral valve surgery, repeated procedures are needed to maintain sinus rhythm.

Ablation of atrial tachycardia in the setting of prior mitral valve surgery

BACKGROUND

Data regarding catheter ablation of post-surgical atrial tachycardia occurring after mitral valve surgery are scarce. Through a search of the literature, this study aimed to assess the feasibility of catheter ablation and the characteristics of atrial arrhythmias ablated in these patients.

METHODS

Studies assessing the main procedure parameters and the electrophysiologic findings of the investigated atrial tachycardia were selected. The electrophysiologic mechanism (focal vs. re-entrant arrhythmias), site of arrhythmia origin (left atrium vs. right atrium) and their anatomic correlation with specific surgical access and/or prior Cox-Maze IV procedure were all addressed.

RESULTS

Eleven studies including 206 patients undergoing catheter ablation of 297 post-surgical arrhythmia morphologies occurring after mitral valve surgery were considered. Major complications were observed in 2 patients only (0.9%). Restoration of sinus rhythm was achieved in 96% of patients. Macro-reentrant arrhythmia was mostly observed (90.4%) with a non-negligible proportion of focal arrhythmia (9.6%). Left-sided arrhythmia was common (54.4%,) but cavotricuspid isthmus-dependent arrhythmia was frequently reported (33%). Although specific atriotomies showed trends towards peculiar locations of the investigated arrhythmia, Cox-Maze IV procedure was the only independent predictor for left-sided arrhythmia (OR=17.3; 95% CI 7.2-41.2; P<0.0001).

CONCLUSIONS

Catheter ablation of post-surgical arrhythmia occurring after mitral valve surgery is feasible, and, in this setting, the vast majority of the arrhythmia morphologies are based on macro-reentry and in about one third of cases show cavotricuspid isthmus-dependent arrhythmia. Prior Cox-Maze-IV associated with mitral valve surgery is an independent predictor of left-sided arrhythmia possibly due to non-transmural surgical lesions.

Prevalence of intra-atrial reentrant tachycardia following mitral valve surgery: Relationship to surgical approach

BACKGROUND AND AIM

Mitral valve (MV) surgeries create electrophysiological substrates that give rise to postoperative arrhythmias. MV surgical procedures have been associated with macro- and microreentrant arrhythmogenic circuits, as well as circuits involving the atrial roof. It is not well understood why such arrhythmias develop; therefore, the aim of this study was to describe clinical and procedure characteristics associated with atrial arrhythmias in patients with prior MV surgery.

METHODS

This retrospective chart review evaluated patients who had prior MV surgery and ablation procedures for atrial tachycardia between 2014 and 2018 (n = 20). Patients were classified into those exhibiting typical atrial flutter or another atrial tachyarrhythmia.

RESULTS

Within the 20 patient cases reviewed, 30 arrhythmias were documented. Two-thirds of arrhythmias were typical atrial flutter; the percent incidence of arrhythmias originating in the right atrial (RA) roof, around the right atriotomy scar, in the left atrium, and at the crista terminalis was 20%, 3%, 7%, and 7%, respectively. Nearly every case of RA roof flutter (n = 5/6) and most arrhythmias (n = 20/30) occurred in patients who had a transseptal approach during MV surgery. Voltage maps did not show clear differences in scarring between groups.

CONCLUSION

Results from this study suggest that an arrhythmogenic substrate for RA roof tachycardias is generated by transseptal approaches for MV surgery. This substrate is not clearly related to a surgical scar. These data suggest that other approaches should be considered for MV surgeries. Additionally, more research is needed to determine the mechanism for this nonscar-related arrhythmia substrate.

Substrate characteristics and ablation outcome of left atrial tachycardia in rheumatic mitral valve disease

BACKGROUND

Right atrial tachycardia (AT) is a common arrhythmia postsurgical valve replacement in patients with rheumatic heart disease (RHD). However, the substrate and the mechanism of left AT in such patients and the ablation efficacy is less known.

METHODS AND RESULTS

Twenty-seven RHD patients with AT were enrolled in this study; nine of them (33%) had left AT. Five and four patients had left AT during the first and second procedure, respectively. A spontaneous scar in the left posterior wall was identified in all patients, and obvious anterior scar in three patients. Dual-roof-dependent AT was found in three patients and macroreentry AT surrounding right pulmonary vein was identified in one patient, two of whom had left anterior scar. Three patients had AT circuit going around the mitral annulus, one of whom had left anterior scar. Entrainment pacing at different sites confirmed the mechanism of these macroreentries. Two patients had a focal origin, one was localized in posterior wall at the edge of the scar and the other one was originated from the left septum with normal voltage. After a mean follow-up of 27.4 ± 7.9 months, the left AT group had a similar recurrence rate compared with the right AT group alone (67% vs 56%, P = 0.58). In the left AT group, 11% of patients had AT recurrence and 56% of patients developed atrial fibrillation.

CONCLUSION

Left atrial AT can occur in RHD patients postmitral valve replacement. Catheter ablation is feasible with high acute success rate. The incidence of late development atrial fibrillation is considerable after successful ablation.

Postoperative atrial tachycardias after mitral valve surgery: Mechanisms and outcomes of catheter ablation

BACKGROUND

Atrial tachycardias (ATs) including atrial fibrillation are common arrhythmias occurring late after mitral valve (MV) surgery, and their management is challenging.

OBJECTIVE

The purpose of this study was to determine the electrophysiological mechanisms of ATs in patients with prior MV surgery and the long-term outcomes of catheter ablation.

METHODS

We studied 67 consecutive patients (mean age 59.4 ± 10.6 years; 41 men [61%]) with prior MV surgery who presented with ATs postoperatively between 2007 and 2015.

RESULTS

AT was clinically documented before the electrophysiology study in 55 patients, whereas in the remaining 12 patients AT was inducible at the study. A total of 99 ATs (35 spontaneous and 64 inducible) were characterized. Overall, the right atrium (RA) was the chamber of origin in 56%. The underlying mechanism was macroreentry in 91 cases and included typical RA flutter (n = 37), mitral annular flutter (n = 21), incisional right AT (n = 16), roof-dependent reentry (n = 12), and local left atrial reentry (n = 5). Eight focal ATs were also documented: 6 from the left atrium and 2 from the RA. Left-sided ATs were more common in patients with prior Maze procedure (53%), and mitral annular flutter was twice as prevalent in this group (42% vs 21%; P = .05). The ablation was acutely successful in 98.5%. Freedom from atrial arrhythmias was 62% at 12 months, with 42% requiring more than 1 procedure.

CONCLUSION

Macroreentry is the predominant AT mechanism in patients with prior MV surgery. Circuits are most often localized to the RA, with left-sided ATs more common in patients with prior Maze procedure. Repeat procedures are common and outcomes with 1 year complete AT control good.

Radiofrequency Ablation of Left Atrial Reentrant Tachycardias in Rheumatic Mitral Valve Disease: A Case Series

BACKGROUND

Left atrial (LA) reentrant tachycardias are not uncommon in regions where rheumatic heart disease is prevalent. Some of these arrhythmias may be curable by radiofrequency ablation (RFA). However, there are limited data pertaining to this in existing literature.

CASE REPORT

Three patients who had rheumatic mitral valve disease with past history of surgical-/catheter-based intervention and having no significant residual disease had symptomatic atrial flutter despite optimal medical management. An electrophysiological study confirmed an LA focal/micro-reentrant mechanism in all. There was patchy scarring of the LA, and successful RFA of these arrhythmias could be achieved.

CONCLUSION

The focal nature of the scar in these patients may suggest that the rheumatic involvement of the atrium or the hemodynamic consequence of the vulvar lesion causes nonuniform insult to the atrial tissue and limited scar. At least in some patients with limited scarring, early RFA may help in the maintenance of sinus rhythm.

Ablation of Atrial Fibrillation in a Patient with a Mechanical Mitral Valve

Clinicians must be mindful of the left ventricular lead when cannulating the coronary sinus with a decapolar catheter or an ablation catheter. Left atrial catheter ablation for the treatment of atrial fibrillation in patients with a mechanical mitral valve, when approached carefully, can be performed safely and effectively. Block across linear lines should be confirmed using differential activation and/or differential pacing to decrease risks of proarrhythmias.

Very long-term outcome of catheter ablation of post-incisional atrial tachycardia: Role of incisional and non-incisional scar

BACKGROUND

The arrhythmogenicity of right atrial (RA) incisional scar after cardiac surgery could result in atrial tachycardia (AT). Radiofrequency catheter ablation is effective in the treatment of such tachycardia. However, data regarding long-term outcomes are limited.

METHODS AND RESULTS

A total of 105 patients with prior RA incision who underwent radiofrequency catheter ablation of AT were included. In the first procedure, electroanatomic mapping (EAM) revealed a total of 139 ATs in 105 patients, including 88 cavotricuspid isthmus dependent atrial flutters (IDAFs), 5 mitral annulus reentrant tachycardias (MARTs), 44 intra-atrial reentrant tachycardias (IARTs) and 2 focal ATs (FATs). AT was successfully eliminated in 101 (96.1%) patients. During a mean follow-up period of 90 ± 36 months, recurrent AT was observed in 23 patients and 21 underwent a second ablation. A total of 23 ATs were identified in redo procedures including 4 IDAFs, 2 MARTs, 12 IARTs and 5 FATs. The time to recurrence was significantly different among various AT types. Acute success was achieved in 20 of 23 redo procedures. Taking a total of 21 patients presenting atrial fibrillation during follow-up into account, 85 patients (81.9%) were in sinus rhythm. No complications except for a case of RA compartmentation occurred.

CONCLUSION

RA incisional scar played an essential role in promoting both IDAF and IART, while non-incisional scar contributed to a substantial rate of late recurrent AT in forms of both macroreentry and small reentry. Catheter ablation using EAM system resulted in a high success rate during long-term follow-up.