Radiofrequency ablation of atrial fibrillation in patients with mechanical mitral valve prostheses safety, feasibility, electrophysiologic findings, and outcomes

Practical approach for atrial cardiomyopathy characterization in patients with atrial fibrillation

Atrial fibrillation (AF) causes progressive structural and electrical changes in the atria that can be summarized within the general concept of atrial remodeling. In parallel, other clinical characteristics and comorbidities may also affect atrial tissue properties and make the atria susceptible to AF initiation and its long-term persistence. Overall, pathological atrial changes lead to atrial cardiomyopathy with important implications for rhythm control. Although there is general agreement on the role of the atrial substrate for successful rhythm control in AF, the current classification oversimplifies clinical management. The classification uses temporal criteria and does not establish a well-defined strategy to characterize the individual-specific degree of atrial cardiomyopathy. Better characterization of atrial cardiomyopathy may improve the decision-making process on the most appropriate therapeutic option. We review current scientific evidence and propose a practical characterization of the atrial substrate based on 3 evaluation steps starting with a clinical evaluation (step 1), then assess outpatient complementary data (step 2), and finally include information from advanced diagnostic tools (step 3). The information from each of the steps or a combination thereof can be used to classify AF patients in 4 stages of atrial cardiomyopathy, which we also use to estimate the success on effective rhythm control.

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.

Acute and long-term success of left atrial anterior line and mitral isthmus line ablation in patients after mitral valve surgery

BACKGROUND

Perimitral flutter and atrial fibrillation may occur in patients with prior surgical mitral valve (MV) repair or replacement and can be challenging for percutaneous catheter ablation. This study sought to determine the feasibility, acute success and durability of catheter ablation of atrial fibrillation or atrial tachycardia by way of a mitral isthmus line (MIL) or an anterior line (AL).

METHODS

A total of 81 patients (49 males, mean age 62±11 years) with prior MV replacement (n = 30) or reconstruction (n = 51) underwent creation of a MIL (34) and/or an AL (72).

RESULTS

Acute bidirectional block of the MIL was successfully achieved in 24/34 cases and of the AL in 64/72 patients. Patients of the control group without prior MV surgery were matched 1:1 with the valve group. In the AL control subgroup, acute bidirectional block was achieved in 65/72 patients. Acute blockage in the MIL control subgroup could be achieved in 31/34 patients. The MIL valve subgroup showed the worst results in terms of durability, whereas a similar trend emerged in the control group and the AL valve subgroup (probability of failure in MIL valve subgroup 2.224 vs. MIL control subgroup 0.605 [Hazard Ratio (HR) = 0.27, 95% confidence interval (CI), 0.11-0.65), p = 0.004]; probability of failure in AL valve subgroup 0.844 vs. AL control subgroup 1.03 [HR = 1.22 (95% CI, 0.66-2.26), p = 0.523]).

CONCLUSIONS

Percutaneous creation of MIL and AL is feasible and safe in patients with prior MV replacement/repair and associated with moderate acute and long-term success rates to achieve bidirectional block. This article is protected by copyright. All rights reserved.

Safety of Catheter Ablation for Atrial Fibrillation in Patients with Mechanical Prosthetic Valves

BACKGROUND

Catheter ablation (CA) for Atrial Fibrillation (AF) is increasingly utilized in the recent years, with promising results. We aimed to investigate the nationwide trends in utilization and procedural complications of CA for AF in patients with mechanical prosthetic valves (MPVs).

METHODS AND RESULTS

We drew data from the US National Inpatient Sample (NIS) database to identify cases of AF ablations in patients with MPVs, between 2003-2015. Sociodemographic and clinical data were collected, and incidence of procedural complications, mortality, and length of stay were analyzed. We compared the outcomes to a propensity matched cohort of patients without MPVs. The study included a weighted total of 1898 CA for AF cases in patients with MPVs. The median age of the study population was 67 (61-75) years and 53% were males. Despite the increasing age and significant uptrend in the prevalence of individual comorbidities and Deyo - Charlson Comorbidity Index (CCI) over the years, the risk of peri-procedural complications and mortality in the study group didn't change between the early (2003-2008) and late (2009-2015) study years. The peri-procedural complication rate (8.4% vs 10.4%, p=0.33) and in-hospital mortality (0.2% vs. 0.2%, p=0.9) did not differ significantly between patients with MPVs and 1901 matched patients without MPVs. Length of stay was higher among patients with prior MPVs compared to the controls (4.0±0.2 vs. 3.3±0.2 days, p=0.011).

CONCLUSION

This nationwide analysis shows that AF ablation in patients with mechanical valve prostheses bares similar risk of periprocedural complications and mortality as in patients without prosthetic valves. This article is protected by copyright. All rights reserved.

Radiofrequency catheter ablation of accessory pathways at the site of prior valve surgery

BACKGROUND

Radiofrequency catheter ablation (RFCA) for accessory pathways (APs) at the site of prior valve surgery (VS) remains challenging. We aimed to clarify the factors associated with successful RFCA for such APs.

METHODS

Upon reviewing a RFCA registry and previous case reports, we included nine patients who underwent RFCA of APs at the site of prior VS (total-VS group; age, 34.0 [24.5-45.0] years; men, 4/9) and 196 patients who underwent RFCA of APs with no history of VS (no-VS group; age, 40.5 [23.0-54.0] years; men, 114/196). Electrophysiological features, procedural details, and outcomes were examined.

RESULTS

Accessory pathway exhibited decremental conduction in four of nine patients in the total-VS group. The number of RFCA attempts was significantly higher in the total-VS group than in the no-VS group (10.0 [4.5-14.5] vs 2.0 [1.0-3.0]; P < 0.001). In four patients who underwent mitral VS, successful RFCA was achieved using the transaortic approach, coronary sinus (CS) approach, or bipolar ablation. In three patients who underwent tricuspid VS, successful RFCA was achieved using the above-prosthetics or trans-prosthetics approach. In two patients, RFCA failed. The trans-prosthetics approach and bipolar ablation technique were effective. The transaortic and CS approaches were occasionally effective. The transseptal approach was ineffective.

CONCLUSIONS

Successful RFCA of APs at the site of prior VS can be achieved by detailed mapping of the areas both above and below the prosthetic valve, as well as by ensuring effective radiofrequency energy delivery using various catheter approaches and RFCA techniques.

Clinical characteristics and rhythm outcome of catheter ablation of hemodynamically corrected valvular atrial fibrillation

BACKGROUND

Although the hemodynamic burden and structural substrate contribute to valvular atrial fibrillation (VAF) mechanisms, the role of catheter ablation has rarely been reported. We investigated the clinical characteristics, mapping findings, and long-term rhythm outcomes after catheter ablation of hemodynamically corrected VAF.

METHODS

We compared 77 patients with VAF (46.8% male, 52.7±8.8 years old, 46.8% paroxysmal AF, 24.7% with maze procedures) and 2244 patients with non-VAF (NVAF) who underwent catheter ablation. Among the VAF patients, 44 (57.1%) had mechanical valve AF (MV-AF) and 33 (42.9%) underwent a prior mitral valvuloplasty (MVP-AF). We analyzed the catheter ablation rhythm outcomes for MV-AF and MVP-AF.

RESULTS

The left atrial (LA) diameter was greater (p<0.001), LA voltage lower (p<0.001), and procedure-related complication rate higher (mainly sinus node dysfunction, p=0.004) for VAF than NVAF. During 70.2±1.8 months of follow-up, the rhythm outcome of VAF did not significantly differ from that of NVAF after catheter ablation (log rank p=0.399), even after excluding patients with maze procedures (log rank p=0.629). The clinical recurrence rates did not differ between the MV-AF and MVP-AF groups (log rank p=0.244), or between patients with prior maze procedures and those without (log rank p=0.651). The main conduction recovery sites of previous maze procedures were the perimitral (84.2%) and cavotricuspid isthmus (84.2%) areas, and recurrence mechanisms were macroreentry (63.2%) and focal/microreentry (26.3%) at scar border zones.

CONCLUSIONS

Although hemodynamically corrected VAF was associated with advanced LA remodeling, the rhythm outcome did not significantly differ from that of NVAF after catheter ablation.

Who Needs Catheter Ablation And Which Approach?

Catheter ablation therapy for atrial fibrillation (AF) has gained a significant role during maintenance of sinus rhythm compared to anti-arrhythmic medication. Catheter ablation techniques are also improved and progressed over years in parallel to better understanding of disease mechanisms and technological advancements. However, due to invasive nature of the therapy with its pertinent procedural risks, both appropriate patient selection and use of relevant approach should be considered by all electrophysiologists before decide to perform catheter ablation.

Impact of Surgical Ablation of Atrial Fibrillation on the Progression of Tricuspid Regurgitation and Right-Sided Heart Remodeling After Mitral-Valve Surgery: A Propensity-Score Matching Analysis

BACKGROUND

This study assessed the role of surgical ablation for atrial fibrillation (AF) in decreasing tricuspid regurgitation (TR) and right-sided heart remodeling in patients after mitral valve procedure.

METHODS AND RESULTS

Between 1994 and 2014, 1568 consecutive patients with AF undergoing mitral valve procedure were identified. In 26.0% (n=408), surgical ablation of AF was used. Propensity-score matching (PSM) was performed on the basis of 41 known perioperative risk variables. Survival, reoperation, stroke, and moderate-to-severe TR, as well as echocardiography indices in long-term follow-up, were compared in 406 matched patient pairs (ablated and nonablated groups). The nonablated group showed significantly higher risks of death (hazard ratio [HR], 1.644; 95% CI, 1.081-2.501; P=0.020), reoperation (HR, 2.644; 95% CI, 1.299-5.466; P=0.008), and moderate-to-severe TR (HR, 1.436; 95% CI, 1.059-1.948; P=0.020), associated with a significantly deteriorated cardiac function, progression of TR, and right-sided heart remodeling after 5-year follow-up. In a subgroup comparison of ablated patients with sinus rhythm versus AF recurrence, a PSM analysis was performed at the 5-year follow-up. The recurrent group showed significantly higher risks of moderate-to-severe TR (HR, 2.427; 95% CI, 1.261-4.671; P=0.008). AF recurrence was associated with progressive TR and significant deterioration in right-sided heart remodeling.

CONCLUSIONS

In a retrospective PSM analysis, mitral valve disease with AF was associated with TR progression as well as right-sided heart remodeling, which are alleviated by surgical ablation.

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.

Pouched mitral isthmus is associated with incomplete linear block in atrial fibrillation patients with mechanical mitral valve replacement

BACKGROUND

Previous studies have described the impact of mitral isthmus (MI) anatomy on the likelihood of achieving MI linear block in patients with native mitral valves (NMV) who underwent atrial fibrillation (AF) ablation. However, none have investigated that issue in AF patients with mechanical mitral valve replacements (MMVR).

METHODS AND RESULTS

Twenty-nine consecutive patients who developed symptomatic persistent AF post-MMVR and referred for ablation were enrolled. Twenty-nine patients with NMV who underwent ablation of persistent AF during the same period were matched. With preprocedural cardiac computed tomographic imaging, MI anatomical features of all the participants were analyzed. Pouched MI was observed in 19 (65.5%) MMVR patients versus to 6 (20.7%) controls (P = 0.001). Bidirectional linear block across MI was achieved in 21 (72.4%) MMVR patients and 22 (75.9%) in the controls (P = 0.764). In the multivariable analysis, pouched MI was an independent predictor of incomplete MI block.

CONCLUSIONS

Pouched MI accounts for the majority of AF patients with MMVR and may be associated with incomplete bidirectional linear block of MI.

Case report: paravalvular leak as a complication of percutaneous catheter ablation for atrial fibrillation

An increasing number of reports reveal the safety and efficacy of catheter ablation for atrial fibrillation therapy even in patients with a history of prosthetic heart valve. This case report presents a 60 year old female patient who had a prosthetic mitral paravalvular leak as a complication of radiofrequency ablation. Surgery revealed a 15 mm hole and three broken knots in the posterolateral mitral annulus. This report demonstrates radiofrequency ablation for atrial fibrillation in patients with prosthetic mitral valve may cause a paravalvular leak likely as a result of thermal injury. Moreover, patient can be asymptomatic at first. The clinician should keep in mind such complication and the patient should be evaluated in terms of paravalvular leakage.

Bipolar radiofrequency ablation is useful for treating atrial fibrillation combined with heart valve diseases

BACKGROUND

Atrial fibrillation (AF) is a common arrhymia, and it results in increased risk of thromboembolism and decreased cardiac function. In patients undergoing cardiac surgery, concomitant radiofrequency ablation to treat AF is effective in restoring sinus rhythm (SR). This study is an observational cohort study aimed to investigate the safety and efficacy of bipolar radiofrequency ablation (BRFA) for treating AF combined with heart valve diseases.

METHODS

Clinical data were analyzed retrospectively from 324 cases of rheumatic heart disease combined with persistent AF patients who underwent valve replacement concomitant BRFA. The modified left atrial and the simplified right atrial ablation were used for AF treatments. Of the 324 patients, 248 patients underwent mitral valve replacement and 76 patients underwent double valve replacement. Meanwhile, 54 patients underwent concomitant thrombectomy and 97 underwent tricuspid valvuloplasty. And all of them received temporary pacemaker implantation. The 24 hours holter electrocardiogram (ECG) monitoring and echocardiography was performed before the operation, on the first day after operation, on discharge day, and at 6 and 12 months after operation.

RESULTS

There were 299 patients with SR on the first day after operation (92.30%), 12 patients with junctional rhythm (3.70%), 11 patients with AF (3.39%), and 2 patients with atrial flutter (0.62%). The temporary pacemaker was used in 213 patients (65.74%) with heart rates less than 70 beat/minute in the ICU. Two patients died early and the mortality rate was 0.62%. Two patients had left ventricular rupture and the occurrence rate was 0.62%. They both recovered. There was no degree III atrioventricular blockage and no permanent pacemaker implantation. Overall survival rate was 99.38% (322 cases) with SR conversion rate of 89.13% (287 cases) at discharge. The SR conversion rate was 87.54% and 87.01% at 6 and 12 months after operation. Sinus bradycardia occurred in 3.42% of patients at 6 months after operation and in 3.03% of patients at 12 months after operation. Echocardiography showed that the left atrial diameter was significantly decreased, and ejection fraction and fractional shortening were significantly improved.

CONCLUSIONS

BRFA for treating AF in concomitant valve replacement is safe and with good efficacy.

Advances in catheter ablation: atrial fibrillation ablation in patients with mitral mechanical prosthetic valve

Atrial fibrillation (AF) is common in patients with mitral valve replacement (MVR). Treatment of AF in these subjects is challenging, as the arrhythmia is often refractory to antiarrhythmic drug therapy. Radiofrequency catheter ablation (RFCA) is usually avoided or delayed in patients with MVR due to the higher perceived risks and difficulty of left atrial catheter manipulation in the presence of a mechanical valve. Over the last few years, several investigators have reported the feasibility and safety of RFCA of AF in patients with MVR. Five case-control studies have evaluated the feasibility and safety of RFCA of AF or perimitral flutter (PMFL) in patients with MVR. Overall, a total of 178 patients with MVR have been included (21 undergoing ablation of only PMFL), and have been compared with a matched control group of 285 patients. Total procedural duration (weigthed mean difference [WMD] = +24.5 min, 95% confidence interval [CI] +10.2 min to +38.8 min, P = 0.001), and fluoroscopy time (WMD = +13.5 min, 95% CI +3.7 min to +23.4 min, P = 0.007) were longer in the MVR group. After a mean follow-up of 11.5 ± 8.6 months, 64 (36%) patients in the MVR group experienced recurrence of AF/PMFL, as compared to 73 (26%) patients in the control group, accounting for a trend toward an increased rate of recurrences in patients with MVR (odds ratio [OR] = 1.66, 95% CI 0.99 to 2.78, P = 0.053). Periprocedural complications occurred in 10 (5.6%) patients in the MVR group, and in 8 (2.8%) patients in the control group (OR = 2.01, 95% CI 0.56 to 7.15, P = 0.28). In conclusion, a quantitative analysis of the available evidence supports a trend toward a worse arrhythmia-free survival and a higher absolute rate of periprocedural complications in patients with MVR undergoing RFCA of AF or PMFL, as compared to a matched control group without mitral valve disease. These data would encourage the adoption of RFCA of AF in MVR patients mostly by more experienced Institutions.

Atrial Tachyarrhythmias After Cardiac Transplantation

Cardiac transplant recipients demonstrate a unique substrate for atrial tachyarrhythmias owing to the surgical techniques involved. Surgical modification of the atria during transplant surgery has both proarrhythmic and antiarrhythmic effects detailed in this paper. Cavotricuspid isthmus-dependent right atrial flutter is the most common arrhythmia identified. Atrial fibrillation is uncommon owing to obligatory surgical pulmonary vein isolation. Donor hearts can also contain pre-existing accessory pathways or dual AV nodal physiology causing supraventricular tachycardia for which adenosine treatment is not recommended, but catheter ablation is curable.