Left atrial concomitant surgical ablation for treatment of atrial fibrillation in cardiac surgery: A meta-analysis of randomized controlled trials

INTRODUCTION

Surgical ablation is a generally established treatment for patients with atrial fibrillation undergoing concomitant cardiac surgery. Left atrial (LA) lesion set for ablation is a simplified procedure suggested to reduce the surgery time and morbidity after procedure. The present meta-analysis aims to explore the outcomes of left atrial lesion set versus no ablative treatment in patients with AF undergoing cardiac surgery.

METHODS

A literature research was performed in six database from their inception to July 2017, identifying all relevant randomized controlled trials (RCTs) comparing left atrial lesion set versus no ablative treatment in AF patient undergoing cardiac surgery. Data were extracted and analyzed according to predefined clinical endpoints.

RESULTS

Eleven relevant RCTs were included for analysis in the present study. The prevalence of sinus rhythm in ablation group was significantly higher at discharge, 6-month and 1-year follow-up period. The morbidity including 30 day mortality, late all-cause mortality, reoperation for bleeding, permanent pacemaker implantation and neurological events were of no significant difference between two groups.

CONCLUSIONS

The result of our meta-analysis demonstrates that left atrial lesion set is an effective and safe surgical ablation strategy for AF patients undergoing concomitant cardiac surgery.

Bronchial effects of cryoballoon ablation for atrial fibrillation

BACKGROUND

Damage to extracardiac structures, including the esophagus and phrenic nerve, is a known complication of cryoballoon ablation (CBA) during pulmonary vein (PV) isolation for atrial fibrillation (AF). Other adjacent structures, including the pulmonary bronchi and lung parenchyma, may be affected during CBA at the PV ostia.

OBJECTIVE

The purpose of this study was to prospectively study the bronchial effects of CBA in humans undergoing CBA for PV isolation.

METHODS

Ten patients undergoing CBA for AF under general anesthesia were enrolled in an institutional review board-approved prospective observational study. Real-time bronchoscopy was performed during cryoablation of PVs adjacent to pulmonary bronchi to monitor for thermal injury. Patients were followed for the development of respiratory complaints postprocedure.

RESULTS

In 7 of 10 patients (70%) and in 13 of 22 freezes (59%), ice formation was visualized in the left mainstem bronchus during CBA in the left upper PV. Ice formation was not seen in the right mainstem bronchus during right upper PV CBA. The average time to ice formation was 89 seconds. There was no significant difference (P = -.45) in average minimum balloon temperature during freezes with ice formation (-48.5°C) and freezes without ice formation (-46.3°C). No patients went on to develop respiratory complications.

CONCLUSION

Unrecognized ice formation occurs frequently in the left mainstem bronchus during CBA for AF. This information helps explain the source of cough and hemoptysis in some patients who undergo CBA. The long-term consequences of this novel finding and the implications for procedural safety are unknown.

Impact of targeting adenosine-induced transient venous reconnection in patients undergoing pulmonary vein isolation for atrial fibrillation: a meta-analysis of 3524 patients

AIMS

Atrial fibrillation recurrences after pulmonary vein isolation (PVI) are not uncommon and are frequently related to pulmonary vein reconnection. Adenosine/ATP can reveal dormant pulmonary vein conduction after PVI. Previous studies revealed that adenosine-guided Additional ablation could improve arrhythmia-free survival. We performed a meta-analysis to assess the impact of additional ablation to eliminate adenosine-induced transient pulmonary vein reconnection in terms of atrial fibrillation recurrence at follow-up.

METHODS

MEDLINE/PubMed, Cochrane Library and references reporting atrial fibrillation ablation and adenosine/ATP-following PVI were screened, and studies were included if they matched inclusion and exclusion criteria.

RESULTS

A total of 3524 patients were enrolled with a median follow-up of 13 (6-20) months. Overall, 70% (60-85) of patients in ATP-guided ablation vs. 63% (48-79) in no ATP-guided ablation were free of atrial fibrillation at follow-up. Pooled results revealed that ATP-guided ablation reduced the risk of atrial fibrillation recurrence of 42% [odds ratio (OR) 0.58, 0.41-0.81], but this result was primary because of the contribution of retrospective over-randomized studies [OR 0.48 (0.35-0.65) vs. 0.76 (0.42-1.40), respectively]. 3.2% of patients experienced an adverse event. ATP-guided ablation is related to a nonsignificant increase in fluoroscopy time (OR 1.71, 0.98-2.96) and to a significant increase in procedure time (OR 2.84, 1.32-6.09).

CONCLUSION

Additional ablation aiming to eliminate adenosine-induced transient pulmonary vein reconnection failed to reduce the risk of atrial fibrillation recurrence at follow-up. Moreover, although adenosine-guided PVI is not affected by an augmented risk of adverse events, it is associated with a NS increased fluoroscopy exposure and significantly longer procedure duration. Further studies are required to identify the actual role of adenosine in PVI.

The safety and efficacy of hybrid ablation for the treatment of atrial fibrillation: A meta-analysis

Introduction

Hybrid ablation, an emerging therapy that combines surgical intervention and catheter ablation, has become a viable option for the treatment of persistent atrial fibrillation. In this analysis, we aimed to evaluate the safety and efficacy of hybrid ablation, as well as compare the outcomes of one-step and staged approaches.

Methods

We conducted a search in major online databases and selected the studies that met the inclusion criteria. The primary endpoint was defined as no episode of atrial fibrillation or atrial tachycardia lasting longer than 30 seconds without administration of antiarrhythmic drugs.

Results

Sixteen studies including 785 patients (paroxysmal atrial fibrillation, n = 83; persistent atrial fibrillation, n = 214; long-standing persistent atrial fibrillation, n = 488) were selected. Average history of atrial fibrillation was (5.0±1.6) years. The pooled proportion of patients who were arrhythmia-free at the primary endpoint was 73% (95% CI, 64%–81%, Cochran’s Q, P<0.001; I² = 81%). The pooled rate of severe short-term complications was 4% (95% CI, 2%–7%, Cochran’s Q, P = 0.01; I² = 51%). The success rate after one-step procedures (69%) was lower than that after staged procedures (78%). The staged approach could ultimately prove to be safer, although complication rates were relatively low for both approaches (2% and 5%, respectively).

Conclusions

Hybrid ablation is an effective and generally safe procedure. The current data suggest that staged hybrid ablation could be the optimal approach, as it is associated with a higher success rate and a seemingly lower complication rate. Additional randomized controlled trials are necessary to confirm these results.

Practical Techniques in Cryoballoon Ablation: How to Isolate Inferior Pulmonary Veins

Catheter ablation is the most effective treatment option for patients suffering from symptomatic atrial fibrillation. Electrical isolation of the pulmonary veins is the procedural cornerstone. Point-by-point radiofrequency current energy ablation in combination with a 3D electro-anatomical mapping system is the established approach to ablation. In contrast, cryoballoon ablation uses a single-shot approach to facilitate pulmonary vein isolation. However, fixed cryoballoon diameters (28 mm or 23 mm) and non-balloon compliance can lead to technical difficulties in isolating variable pulmonary vein anatomies. This review focuses on key procedural aspects and illustrates practical techniques in cryoballoon pulmonary vein isolation to shorten the learning curve without compromising safety and efficacy. It has a special emphasis on inferior pulmonary veins.

How to Prevent, Detect and Manage Complications Caused by Cryoballoon Ablation of Atrial Fibrillation

Atrial fibrillation is the most common cardiac arrhythmia and the prevalence is increasing every year. Patients who fail to maintain sinus rhythm with use of anti-arrhythmic drug therapy are referred for catheter ablation. Cryoballoon (CB) ablation has emerged as an effective and alternative treatment option to traditional point-by-point radiofrequency ablation, but there can be complications. This article reviews the incidence, presentation, risk factors, management and preventative strategies of three major complications associated with CB ablation: phrenic nerve injury, atrial oesophageal fistula and bronchial injury. Although these complications are rare, electrophysiologists should institute measures to identify high-risk patients, implement best-practice techniques to minimise risks and maintain a high index of suspicion to recognise the complications quickly and implement correct treatment strategies.

Sinus Rhythm Restoration after Radiofrequency Ablation Improves Survival in Patients Undergoing Mitral Valve Surgery : A Eight Year Single Center Study

Background

The usefulness of radiofrequency (RF) ablation in restoring sinus rhythm in patients with permanent atrial fibrillation (AF) undergoing surgery for mitral valve has been demonstrated. But whether sinus rhythm recovery affects long-term survival is less clear.

Methods

This study included 301 consecutive patients (126 men and 175 women, age 69±6 years) undergoing radiofrequency ablation of persistent atrial fibrillation along with mitral valve surgery. Radiofrequency ablation was performed using unipolar probe in 55.3%, bipolar probe in the remaining 44.7% of cases.

Results

Four patients died during hospitalization. At follow-up, sinus rhythm was present in 76% of the surviving patients. 71 patients never recovered sinus rhythm after hospital discharge. Mortality and recurrent hospitalization were significantly lower in patients with sinus rhythm at the end of follow-up in comparison to permanent AF. The incidence of stroke was also lower in patients with stable sinus rhythm. Larger atria, pulmonary hypertension and history of rheumatic disease were associated with the persistence of AF despite radiofrequency ablation. Although survival and functional capacity were significantly lower in patients with permanent AF at multivariate analysis only age and pulmonary artery pressure before surgery were independently associated with mortality.

Conclusion

Sinus rhythm restoration by RF ablation in patients undergoing mitral valve surgery is associated with an improved long-term survival. However our results suggest that a more severe hemodynamic impairment, expressed by higher pulmonary artery pressure, and increasing age are the only independent factors related to long-term survival.

Reconnection Rate and Long-Term Outcome with Adenosine Provocation During Cryoballoon Ablation for Pulmonary Vein Isolation

Background

Adenosine can unmask dormant conduction during pulmonary vein isolation (PVI) for atrial fibrillation (AF). Studies of adenosine use in radiofrequency PVI show high reconnection rates and conflicting results for long-term success, however there is limited data with cryoballoon ablation (CBA).

Methods

A prospectively maintained database of patients undergoing first CBA at a single institution was analyzed. Adenosine use was at the discretion of the primary operator. Additional freezes were delivered for reconnected veins until dormant conduction was eliminated. The primary endpoint, time to AF recurrence defined as any episode < 30 seconds after a 3-month blanking period, was assessed by Kaplan-Meier analysis.

Results

From 2011 to 2015, 406 patients underwent CBA, 361 of whom had > 3 months follow-up. The mean age was 61.7 years, 69% were male, and the prevalence of paroxysmal AF was 79% with no significant difference between those that did and did not receive adenosine (77% vs 86%, respectively, p = 0.23). Adenosine testing was performed in 78 patients (21.6%) with a mean dose of 10.6 mg/vein. Of the 306 veins evaluated, 17 (6%) demonstrated dormant conduction. Over a median 14.4 months follow-up, there was no significant difference in freedom from AF with adenosine use (p= 0.86).

Conclusions

Dormant conduction with adenosine is uncommon following CBA and its use does not improve long-term success rates.

New migraine with visual disturbance after cryoballoon ablation of atrial fibrillation

We report the case of a 58-year-old woman who developed a headache and visual disturbances after a cryoballoon ablation procedure for atrial fibrillation at our institution. She presented to the emergency department four days post ablation and was admitted the hospital for overnight observation. Serial neurological examinations and neuroimaging were unremarkable for stroke or transient ischemic attack. The patient had some brief transient visual changes which resolved completely after several days, with no further clinical sequelae. She followed up in the outpatient neuro-ophthalmology clinic and had a normal visual field examination. She was given a diagnosis of new onset migraine with visual aura.

Effectiveness and safety of simultaneous hybrid thoracoscopic endocardial catheter ablation of atrial fibrillation in obese and non-obese patients

Background

We evaluated the safety and effectiveness of the hybrid thoracoscopic endocardial epicardial ablation technique for the treatment of atrial fibrillation (AF) in obese versus non-obese patients.

Methods

Between January 2010 and January 2015, a cohort of 61 patients were retrospectively identified to undergo ablation of AF as a stand-alone procedure using a thoracoscopic, hybrid epicardial-endocardial technique. All patients underwent continuous 7-day Holter monitoring at 3, 6 months, 1 year and yearly thereafter.

Results

A total of 40% of the obese cohort had persistent or long-standing AF, compared to 54.9% of the non-obese cohort. There were no deaths or conversion to cardiopulmonary bypass required. At 3-year follow-up, 60% of the obese group were in sinus rhythm (SR) with no episode of AF, atrial flutter or atrial tachycardia lasting 30 s off anti-arrhythmic drugs. This was compared to 70.6% in the non-obese group, with no significant difference between the groups (P=0.468). For success rates on anti-arrhythmic drugs, this was 80% in the obese group compared to 86% in the non-obese group at 3-year follow-up (P=0.637). No patient died and no thromboembolic/bleeding events or procedure-related complications occurred during the follow-up.

Conclusions

In a retrospective cohort with approximately half with persistent or long-standing AF, thoracoscopic hybrid epicardial endocardial ablation proved to be equally effective and safe in obese versus non-obese patients. Current preliminary findings require further validation in multi-institutional prospective studies with larger sample sizes.

Identification and Ablation of Dormant Conduction in Atrial Fibrillation Using Adenosine

BACKGROUND

Ablation is used for treatment of atrial fibrillation (AF) but recurrence is common. Dormant conduction is hypothesized to be responsible for these recurrences, and the role of adenosine in identification and ablation of these pathways is controversial with conflicting results on AF recurrence.

MATERIALS AND METHODS

We conducted a meta-analysis for studies evaluating AF ablation and adenosine use. Included in the meta-analysis were human studies that compared ablation using adenosine or adenosine triphosphate (ATP) and reported freedom from AF in patients beyond a minimum follow-up of 6 months.

RESULTS

Our analysis suggests that the use of adenosine leads to a decrease in recurrence of AF compared to the cohort which did not utilize adenosine. Subgroup analysis showed no difference in the recurrence of AF with the modality used for ablation (cryoablation vs. radiofrequency ablation) or with the preparation of adenosine used (ATP vs. adenosine). There was a significant benefit in delayed administration of ATP over early administration. Pooling results of only randomized control trials did not show any significant difference in AF recurrence.

CONCLUSIONS

Adenosine-guided identification and ablation of dormant pathways may lead to a decrease in recurrence of AF.

Vascular complications following intra-aortic balloon pump implantation: an updated review

Background:

The use of the intra-aortic balloon pump (IABP) as a support device remains controversial due to the fact that a number of studies have shown no benefit in end mortality whilst using this device. One of the reasons for this could be the increase in vascular complications when using the pump. Therefore, the aim of the present review was to assess the current literature available with regards to IABP vascular complications during the clinical situation.

Methods:

A literature search was performed, searching for IABP complications in adult human studies between 1990 and 2016.

Results:

A total of 20 reports were identified as fitting the criteria of this study. The majority of vascular complications were limb ischemia, bleeding or mesenteric ischemia. The overall incidence of vascular complications ranged from 0.94% to 31.1%. Diabetes, peripheral vascular disease and hypertension, as well as smoking were all identified as risk factors for complications following IABP. Furthermore, studies supported the use of sheathless balloon insertion to reduce the risk of complications.

Conclusion:

Major vascular complications, including limb and mesenteric ischemia as well as bleeding and hemorrhage, have been associated with IABP. However, the incidence of these complications was generally low. Further studies are still required to truly understand the risk/benefit associated with the use of IABP.

Adenosine Testing After Atrial Fibrillation Ablation: Systematic Review and Meta-Analysis

BACKGROUND

Adenosine can be used to reveal dormant pulmonary vein (PV) conduction after pulmonary vein isolation (PVI) for the treatment of atrial fibrillation (AF). We performed a systematic review and meta-analysis to assess the impact of adenosine administration in patients undergoing PVI for AF.

METHODS

Meta-analysis of 22 studies was performed to assess the rates of freedom from AF in 1) patients with dormant PV conduction versus patients without dormant PV conduction, and 2) patients given routine adenosine post PVI versus patients not given adenosine. Relative-risks (RR) were calculated using random effects modelling.

RESULTS

In 18 studies, 3038 patients received adenosine and freedom from AF in those patients with dormant PV reconnection was significantly lower (62.9%) compared to patients without PV reconnection (67.2%) (RR 0.87; 95% CI: 0.78-0.98). In seven studies with 3049 patients, the freedom from AF was significantly higher in patients who received adenosine (67%) versus those patients who did not receive adenosine (63%) (RR: 1.11; 95% CI: 1.01-1.22).

CONCLUSIONS

The present study showed clear benefits of adenosine testing for freedom from AF recurrence. Adenosine-guided dormant conduction is associated with higher AF recurrence despite further ablation. Future studies should investigate the optimal methodology, including dosage and waiting time between PVI and adenosine administration.

Complications caused by adenosine during catheter ablation of atrial fibrillation

Adenosine is increasingly used to assess for dormant conduction following pulmonary vein isolation during atrial fibrillation ablation. While the half‐life of adenosine is typically short and side effects transient, operators should be aware of more serious, lasting adverse reactions including anaphylaxis and bronchospasm.

Use of dabigatran vs. warfarin with low-molecular-weight heparin bridging in catheter ablation for atrial fibrillation patients with a low CHADS2 score

The purpose of the present study was to compare the efficacy and safety of dabigatran and interrupted warfarin with low-molecular-weight heparin bridging in non-valvular atrial fibrillation (AF) catheter ablation. Previously, there has been concerns that bridging therapy increases bleeding events without the benefit of stroke prevention. It has been suggested that bridging therapy should be considered only for patients at high-risk of thrombosis. Nevertheless, bridging therapy in AF patients with a low CHADS2 score may be safe and effective. The authors performed a prospective, observational study that included consecutive 240 patients undergoing AF ablation in P.R. China. A total of 139 patients received 110 mg dabigatran twice daily and 101 patients took dose-adjusted warfarin that had been bridged with low-molecular-weight heparin. The mean patient age was 55.48 years with 72.1% being men and 74.2% having paroxysmal AF. One thromboembolic complication occurred in the dabigatran group compared to none in the warfarin group. Both the groups presented a similar major bleeding rate, total bleeding rate, and bleeding and thromboembolic complications. In patients undergoing AF ablation, the risk of bleeding or thromboembolic complications was similar for both dabigatran and interrupted warfarin with bridging therapy. Bridging therapy appeared to be safe and effective for the low-risk population.

Surgical and Hybrid Ablation of Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia in humans and is known to be associated with an increased risk of stroke, dementia, heart failure and mortality. Non-pharmacological therapy with ablation using either surgical or percutaneous techniques is recommended in drug refractory AF. Early attempts to devise procedures to ablate AF and restore sinus rhythm culminated with the Cox-Maze procedure, the first truly successful procedure. Since then, ablation surgery has been conducted predominately as a concomitant procedure. The Cox Maze procedure is complex and technically demanding and has, therefore, been extensively modified with new techniques for creating the linear ablation lines, new lesion sets, minimally invasive surgical techniques and most recently hybrid surgical-catheter ablation techniques. Surgical ablation techniques result in a marked reduction in atrial fibrillation when compared to conventional therapy with only a small increase in procedural risk. However, further research is required to more accurately quantify those benefits and to determine the optimal lesion sets, specific to the underlying arrhythmia mechanism and the optimal energy sources for ablation.

Current Interventional and Surgical Management of Congenital Heart Disease: Specific Focus on Valvular Disease and Cardiac Arrhythmias

Successful outcome in the care of patients with congenital heart disease depends on a comprehensive multidisciplinary team. Surgery is offered for almost every heart defect, despite complexity. Early mortality for cardiac surgery in the neonatal period is ≈10% and beyond infancy is <5%, with 90% to 95% of patients surviving with a good quality of life into the adult years. Advances in imaging have facilitated accurate diagnosis and planning of interventions and surgical procedures. Similarly, advances in the perioperative medical management of patients, particularly with intensive care, has also contributed to improving outcomes. Arrhythmias and heart failure are the most common late complications for the majority of defects, and reoperation for valvar problems is common. Lifelong surveillance for monitoring of recurrent or residual structural heart defects, as well as periodic assessment of cardiac function and arrhythmia monitoring, is essential for all patients. The field of congenital heart surgery is poised to incorporate new innovations such as bioengineered cells and scaffolds that will iteratively move toward bioengineered patches, conduits, valves, and even whole organs.

Surgical Treatment of Atrial Fibrillation in Patients with Rheumatic Valve Disease

OBJECTIVE:

To assess heart rhythm and predictive factors associated with sinus rhythm after one year in patients with rheumatic valve disease undergoing concomitant surgical treatment of atrial fibrillation. Operative mortality, survival and occurrence of stroke after one year were also evaluated.

METHODS:

Retrospective longitudinal observational study of 103 patients undergoing rheumatic mitral valve surgery and ablation of atrial fibrillation using uni- or bipolar radiofrequency between January 2013 and December 2014. Age, gender, functional class (NYHA), type of atrial fibrillation, EuroSCORE, duration of atrial fibrillation, stroke, left atrial size, left ventricular ejection fraction, cardiopulmonary bypass time, myocardial ischemia time and type of radiofrequency were investigated.

RESULTS:

After one year, 66.3% of patients were in sinus rhythm. Sinus rhythm at hospital discharge, lower left atrial size in the preoperative period and bipolar radiofrequency were associated with a greater chance of sinus rhythm after one year. Operative mortality was 7.7%. Survival rate after one year was 92.3% and occurrence of stroke was 1%.

CONCLUSION:

Atrial fibrillation ablation surgery with surgical approach of rheumatic mitral valve resulted in 63.1% patients in sinus rhythm after one year. Discharge from hospital in sinus rhythm was a predictor of maintenance of this rhythm. Increased left atrium and use of unipolar radiofrequency were associated with lower chance of sinus rhythm. Operative mortality rate of 7.7% and survival and stroke-free survival contribute to excellent care results for this approach.

Mechanistic Insights Into Durable Pulmonary Vein Isolation Achieved by Second-Generation Cryoballoon Ablation

Background

The mechanism explaining the efficacy of cryoballoon ablation (CBA) for atrial fibrillation has not been clarified.

Methods and Results

We compared lesion characteristics between patients in whom pulmonary vein isolation (PVI) was performed by CBA (n=56) and those by contact force (CF)-based RF ablation (n=56). We evaluated the 3-dimensional PV morphology before and after cryoballoon inflation. After PVI, a 3D left atrial voltage map was created. Pacing (10 mA and 2 ms) was performed within the low voltage area from the ablation line, and electrically unexcitable ablated tissue was identified. ATP-provoked dormant conduction after PVI occurred in 9 of the 224 (4%) PVs in the CBA group and in 13 of the 224 (6%) PVs in the CF group (P=0.3935). The inflated balloon stretched the PV from the original PV ostial surface by 7.1±3.5 mm, but at sites with (vs, sites without) residual PV potential/dormant conduction, the extent of the PV distension was reduced (4.0±4.0 mm vs. 7.2±3.4 mm, P<0.0001). The unexcitable ablated tissue around the PVs was significantly wider in CB patients than in CF patients (16.7±5.1 mm vs. 5.3±2.3 mm, P<0.0001).

Conclusions

Use of the cryoballoon significantly distends the PV. Without this extensive distention, PVI may not be successful. CBA seems to yield wide unexcitable ablation zones. These factors seem to explain the durability of CBA lesions.

Role of adenosine-guided pulmonary vein isolation in patients undergoing catheter ablation for atrial fibrillation: a meta-analysis

AIMS

Adenosine had been reported to unmask dormant conduction and thus identify pulmonary vein at risk of reconnection. However, the role of adjunctive adenosine infusion after pulmonary vein isolation (PVI) on long-term arrhythmia-free survival was still contentious. The purpose of the present meta-analysis was to assess the association of adenosine testing with long-term ablation success in patients with atrial fibrillation (AF) (i.e. freedom from AF recurrence).

METHODS AND RESULTS

We systematically searched the electronic databases and finally included 10 studies, with 1771 patients undergoing adenosine-guided PVI and 1787 patients undergoing conventional PVI. In comparison to conventional PVI alone, adenosine-guided PVI improved the arrhythmia-free survival by 17% during a median follow-up of 12 months [relative risk (RR): 1.17; 95% confidence interval (CI): 1.07 to 1.27; P = 0.014]. Patients undergoing adenosine-guided PVI had similar fluoroscopy time to those who undergoing conventional PVI [weighted mean difference (WMD): 1.76; 95% CI: -5.66 to 9.17; P = 0.64], despite longer procedure time (WMD: 20.6; 95% CI: 0.70 to 40.50; P = 0.042).

CONCLUSION

From the available data of clinical studies, adenosine-guided PVI was associated with an increased arrhythmia-free survival when compared with conventional PVI in patients undergoing catheter ablation for AF.

Relationship of the lungs to the left atrium of particular relevance for ablation of atrial fibrillation

BACKGROUND

Symptoms of possible lung and pleural injury such as chest pain and hemoptysis occur during and after radiofrequency ablation (RFA) and cryoablation (CA) of the left atrium (LA) for treatment of atrial fibrillation (AF). We determined the anatomical relationship of the lungs to the LA with particular reference to areas commonly targeted during AF ablation.

METHODS

Distances from the LA endocardium to the lungs were measured from pre-procedure CT angiograms of 100 consecutive patients (71 males, age 60 ± 8 years) who underwent AF ablation.

RESULTS

In 97% of the patients, the posterior right pulmonary vein antrum was <5 mm from the lower lobe of the right lung (RLL) over a supero-inferior distance of 3.6 ± 1.5 cm (minimum distance 1.2 ± 0.7 mm). The right inferior pulmonary vein (RIPV) ostium was <5 mm from the RLL in 94% (mean 2.7 ± 1.9 mm). The right superior pulmonary vein ostium was <5 mm from the RLL in 29% (mean 7.1 ± 3.8 mm). The medial segment of the right middle lobe was <5 mm from the carina between right pulmonary veins in 83% (mean 3.6 ± 1.9 mm). The mitral isthmus was <5 mm from the lingula in 5% (mean 9.4 ± 3.6 mm). The inferior lobe of the left lung was <5 mm from the posterior aspect of the ostia of the left inferior and superior pulmonary veins in 9 and 0%, respectively. The bronchi were <5 mm from the LA in 5%.

CONCLUSIONS

The lungs are intimately related to sites of the LA commonly targeted during AF RFA. Whether this anatomical proximity translates into clinically significant potential for collateral lung damage during RFA merits further study.

Characteristics of the new AtriCure cryoFORM® cryoablation probe for the surgical treatment of cardiac arrhythmias

INTRODUCTION

Atrial fibrillation has a significant impact on patient mortality and morbidity. In particular, stroke is a frequent complication associated with atrial fibrillation. In recent years, various treatment options have been developed that are based on the elimination of atypical electrically active atrial areas. Areas covered: This manuscript presents a new cryoablation probe from AtriCure Inc. In addition to describing the characteristics of the probe, we also discuss atrial fibrillation and its surgical therapy options as well as the basics of cryosurgery. The cryoFORM® cryoablation probe is an ablation system developed for cardiothoracic surgeons that utilizes nitrous oxide (N₂O) to create continuous transmural lesions that block propagation of atrial activation. The main features of the probe are an excellent working capacity due to the use of N₂O, high flexibility, and, in combination with the cryoICE® Box V6, an active defrost mode for quick detachment. Expert commentary: The cryoFORM® ablation probe is a new device for the treatment of atrial fibrillation using N₂O as an energy source. The probe is made from stainless steel and has a corrugated surface, a design that provides a higher flexibility than the cryoICE probe.

Chronic obstructive pulmonary disease and atrial fibrillation: An unknown relationship

Chronic obstructive pulmonary disease (COPD) is independently associated with atrial fibrillation (AF). Decreased oxygenation, hypercapnia, pulmonary hypertension, diastolic dysfunction, oxidative stress, inflammation, changes in atrial size by altered respiratory physiology, increased arrhythmogenicity from nonpulmonary vein foci commonly located in the right atrium, and respiratory drugs have been implicated in the pathogenesis of AF in COPD. The understanding of the relationship between COPD and AF is of particular importance, as the presence of the arrhythmia has significant impact on mortality, especially in COPD exacerbations. On the other hand, COPD in AF is associated with AF progression, success of cardioversion, recurrence of AF after catheter ablation, and increased cardiovascular and all-cause mortality. Treatment of the underlying pulmonary disease and correction of hypoxia and acid-base imbalance represents first-line therapy for COPD patients who develop AF. Cardioselective β-blockers are safe and can be routinely used in COPD. In addition, AF ablation was proved to be efficient and safe, and improves quality of life in these patients. This review presents the association between COPD and AF, describes the pathophysiological mechanisms implicated in AF development in COPD, underlines the prognostic significance of AF in COPD patients and vice versa, and highlights emerging therapeutic approaches in this setting.

Outcomes in hypertrophic cardiomyopathy patients with and without atrial fibrillation: a survival meta-analysis

BACKGROUND

Atrial fibrillation (AF) is a frequent occurrence in patients with hypertrophic cardiomyopathy (HCM). It is associated with worsening symptoms, cardiovascular events, and mortality. We conducted a meta-analysis of studies reporting on mortality in patient with HCM and AF.

METHODS

We searched PubMed, Medline, Embase, Ovid and Cochrane for studies which reported cardiovascular events and mortality in patients with HCM and AF. Outcome was a composite of cardiac mortality and/or all-cause mortality. Mantel Haenszel odds ratio (OR) or hazard ratio (HR) were calculated using random-effects meta-analysis for the prespecified outcome. Heterogeneity was assessed using I² statistics.

RESULTS

Six studies met the inclusion criteria. There were 6,858 patients; 1,314 (19%) had history of AF. During a mean follow up that ranged between 4 and 8 years, 405 (30.8%) patients with AF died as compared to 1,011 (18.2%) patients without AF (OR =2.49, 95% CI: 1.85-3.35, P<0.00001, I²=57%). Results persisted with inclusion of studies only reporting specifically on cardiac mortality (OR =2.80, 95% CI: 1.79-4.39, P<0.00001, I²=56%). Also, the mortality difference persisted after exclusion of deaths secondary to stroke in both groups (2 studies, 1,398 patients, OR =2.57, 95% CI: 1.57-4.20, P=0.0002, I²=31%). In three studies (5,857 patients); the presence of AF was associated with a pooled HR of 1.66 (95% CI: 1.29-2.13, P<0.0001, I²=41%).

CONCLUSION

Patients with HCM who develop AF have higher risk of mortality and cardiac deaths as compared to HCM patients without AF.

We Know What the Cardiac Surgeon Did During Last Hybrid Arrhythmia Procedure

Superior vena cava (SVC) is an important source of origin of atrial fibrillation (AF) triggers other than a pulmonary vein. Because of the proximity of SVC-aorta ganglionic plexi to the SVC and the extension of myocardium in the SVC from the right atrium, SVC frequently becomes an important source of ectopic beats initiating AF. The potential complications of SVC isolation may include sinus node injury. Sinus node isolation was observed in a patient who had undergone previous surgical isolation of SVC for AF, while attempting to ablate endocardially, near the superior part of interatrial septum for an atrial tachycardia.

Pulmonary Vein Isolation with the Cryoballoon Technique: Feasibility, Procedural Outcomes, and Adoption in the Real World: Data from One Shot Technologies TO Pulmonary Vein Isolation (1STOP) Project

BACKGROUND

Catheter ablation (CA) is recommended for patients with drug refractory symptomatic atrial fibrillation (AF). "One Shot" catheters have been introduced to simplify CA and cryoballoon ablation (CBA) is spreading rapidly. Few real-world data are available on standard clinical practice, mainly from single-center experience. We aimed to evaluate clinical settings, demographics, and acute procedural outcomes in a large cohort of patients treated with CBA.

METHODS

A total of 903 patients (73% male, mean age 59 ± 11) underwent pulmonary vein CBA. Correlations between the patient's inclusion time and clinical characteristics, procedure duration, acute success rate, and intraprocedural complications were evaluated.

RESULTS

Seventy-seven percent of patients were affected by paroxysmal AF and 23% by persistent AF. Overall, acute success rate was 97.9% and periprocedural complications were observed in 35 (3.9%) patients, 13 (1.4%) of which were classified as major complications. With respect to the patient's inclusion time analysis, an increase in treatment of persistent AF was observed, a significant decrease in CBA times (procedure, ablation, and fluoroscopy: 136.0 ± 46.5 minutes, 28.8 ± 19.6 minutes, and 34.3 ± 15.4 minutes, respectively) was observed, with comparable acute success rate and intraprocedural complications over time. The rate of major complications was extremely low (1.4%); no death, atrioesophageal fistula, stroke, or other major periinterventional or late complications occurred.

CONCLUSION

This series represents the largest experience of CBA in the treatment of AF that also describes the adoption curve of this relatively recent technology. CBA showed an excellent safety profile when performed in a large real-world clinical setting, with satisfactory acute success rate and, on average, short procedural times.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov (NCT01007474).

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.

Contact Force and Atrial Fibrillation Ablation

Catheters able to measure the force and vector of contact between the catheter tip and myocardium are now available. Pre-clinical work has established that the degree of contact between the radiofrequency ablation catheter and myocardium correlates with the size of the delivered lesion. Excess contact is associated with steam pops and perforation. Catheter contact varies within the left atrium secondary to factors including respiration, location, atrial rhythm and the trans-septal catheter delivery technology used. Compared with procedures performed without contact force (CF)-sensing, the use of this technology has, in some studies, been found to improve complication rates, procedure and fluoroscopy times, and success rates. However, for each of these parameters there are also studies suggesting a lack of difference from the availability of CF data. Nevertheless, CF-sensing technology has been adopted as a standard of care in many institutions. It is likely that use of CF-sensing technology will allow for the optimization of each individual radiofrequency application to maximize efficacy and procedural safety. Recent work has attempted to define what these optimal targets should be, and approaches to do this include assessing for sites of pulmonary vein reconnection after ablation, or comparing the impedance response to ablation. Based on such work, it is apparent that factors including mean CF, force time integral (the area under the force-time curve) and contact stability are important determinants of ablation efficacy. Multicenter prospective randomized data are lacking in this field and required to define the CF parameters required to produce optimal ablation.

Is visceral flow during intra-aortic balloon pumping size or volume dependent?

AIM

We evaluated the influence of intra-aortic balloon size and volume on mesenteric and renal flows.

METHODS

Thirty healthy swine underwent 120-minute ligation of the left anterior descending coronary artery followed by 6 hours of reperfusion. Then, they were randomly assigned to the following five groups of animals, with six animals in each group: no intra-aortic balloon pump (IABP), a short 35-mL IABP, a short 40-mL IABP, a long 35-mL IABP and a long 40-mL IABP. Superior mesenteric artery (SMA) and renal flows were measured at baseline (t₀), at 2-hour ischemia (t₁) and every hour thereafter until 6 hours of reperfusion (from t_R1 to t_R6).

RESULTS

SMA flows increased significantly at t_R1 only in the two short IABP groups (p<0.001) and balloon volume did not appear to affect flows which, at any experimental time-point, were comparable using 35 mL or 40 mL balloons (p>0.05). Renal flows appeared to be influenced by balloon length, but not by volume. Indeed, flows in the renal arteries rose during IABP treatment; the increase was significantly higher in the short balloon groups and throughout the whole reperfusion (all, p<0.001).

CONCLUSIONS

Changes in visceral perfusion during IABP assistance were significantly related to balloon length, but not to its volume. This could be relevant for the evolution of balloon engineering design in order to reduce the incidence of mesenteric ischemia following IABP. Further research is necessary to confirm these findings.

Effective contact and outcome after pulmonary vein isolation in novel circular multi-electrode atrial fibrillation ablation

Introduction

Pulmonary vein (PV) reconnection is frequently the cause of recurrence of atrial fibrillation (AF) after ablation. The second-generation gold multi-electrode ablation (Gold-MEA) catheter has a new design possibly resulting in improved lesion formation compared with its predecessor. We aimed to determine the association between effective radiofrequency applications with the Gold-MEA catheter and outcome after AF ablation.

Methods

50 consecutive patients with paroxysmal AF underwent Gold-MEA (PVAC GOLD^TM, Medtronic Inc.) ablation. The Gold-MEA catheter was navigated to the PV ostium by fluoroscopy. Duty-cycled radiofrequency ablations were performed at all PV ostia. Lesions were considered transmural when electrode temperature was >50 °C and power >3 W for >30 seconds. After the ablation procedure, patients visited the outpatient clinic at 3‑month intervals including 24-hour Holter ECGs.

Results

Mean age was 56 years. All PVs were acutely isolated with the Gold-MEA catheter. Procedure time was 111 ± 22 minutes, ablation time was 24 ± 6.7 minutes and fluoroscopy time was 20 ± 8.1 minutes. No procedure-related complications were observed. One year after ablation, 60 % of patients were still free of arrhythmia recurrences after a single PV isolation attempt. The number of transmural lesions was associated with arrhythmia-free survival: 25.0 % in <72 transmural lesions, 64.3 % in 72–108 transmural lesions and 71.4 % in >108 transmural lesions (p = 0.029).

Conclusion

PV isolation can be performed successfully with the Gold-MEA catheter, with a favourable safety profile. Transmurality of lesions was associated with ablation success and may improve AF ablation success.

Update on hypertrophic cardiomyopathy and a guide to the guidelines

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiovascular disorder, affecting 1 in 500 individuals worldwide. Existing epidemiological studies might have underestimated the prevalence of HCM, however, owing to limited inclusion of individuals with early, incomplete phenotypic expression. Clinical manifestations of HCM include diastolic dysfunction, left ventricular outflow tract obstruction, ischaemia, atrial fibrillation, abnormal vascular responses and, in 5% of patients, progression to a 'burnt-out' phase characterized by systolic impairment. Disease-related mortality is most often attributable to sudden cardiac death, heart failure, and embolic stroke. The majority of individuals with HCM, however, have normal or near-normal life expectancy, owing in part to contemporary management strategies including family screening, risk stratification, thromboembolic prophylaxis, and implantation of cardioverter-defibrillators. The clinical guidelines for HCM issued by the ACC Foundation/AHA and the ESC facilitate evaluation and management of the disease. In this Review, we aim to assist clinicians in navigating the guidelines by highlighting important updates, current gaps in knowledge, differences in the recommendations, and challenges in implementing them, including aids and pitfalls in clinical and pathological evaluation. We also discuss the advances in genetics, imaging, and molecular research that will underpin future developments in diagnosis and therapy for HCM.

Challenges and Outcomes of Posterior Wall Isolation for Ablation of Atrial Fibrillation

Background

The left atrial posterior wall (PW) often contains sites required for maintenance of atrial fibrillation (AF). Electrical isolation of the PW is an important feature of all open surgeries for AF. This study assessed the ability of current ablation techniques to achieve PW isolation (PWI) and its effect on recurrent AF.

Methods and Results

Fifty‐seven consecutive patients with persistent or high‐burden paroxysmal AF underwent catheter ablation, which was performed using an endocardial‐only (30) or a hybrid endocardial–epicardial procedure (27). The catheter ablation lesion set included pulmonary vein antral isolation and a box lesion on the PW (roof and posterior lines). Success in creating the box lesion was assessed as electrical silence of the PW (voltage <0.1 mV) and exit block in the PW with electrical capture. Cox proportional hazards models were used for analysis of AF recurrence. PWI was achieved in 21 patients (36.8%), more often in patients undergoing hybrid ablation than endocardial ablation alone (51.9% versus 23.3%, P=0.05). Twelve patients underwent redo ablation. Five of 12 had a successful procedural PWI, but all had PW reconnection at the redo procedure. Over a median follow‐up of 302 days, 56.1% of the patients were free of atrial arrhythmias. No parameter including procedural PWI was a statistically significant predictor of recurrent atrial arrhythmias.

Conclusions

PWI during catheter ablation for AF is difficult to achieve, especially with endocardial ablation alone. Procedural achievement of PWI in this group of patients was not associated with a reduction in recurrent atrial arrhythmias, but reconnection of the PW was common.

Atrial flutter after surgical maze: incidence, diagnosis, and management

PURPOSE OF REVIEW

The prevalence of atrial fibrillation is increasing and surgical ablation is becoming more common, both as a stand-alone procedure and when performed concomitantly with other cardiac surgery. Although surgical ablation is effective, with it unique challenges arise, including iatrogenic macroreentrant tachycardias that are often highly symptomatic and difficult to manage conservatively.

RECENT FINDINGS

Postsurgical ablation, localization of the arrhythmic circuit is difficult to determine using surface ECG alone because of alterations in the atrial myocardium, and multiple different pathways are often present. Most, however, localize to the left atrium, and percutaneous catheter ablation is emerging as an effective treatment modality.

SUMMARY

Patients with complex postoperative arrhythmias should be referred to a dedicated atrial fibrillation center when possible and symptomatic arrhythmias mapped and ablated. Knowledge of the previously performed surgical lesion set is of vital importance in understanding the mechanism of the arrhythmia and increasing procedural success rates.

VIDEO ABSTRACT

http://links.lww.com/HCO/A31.

Hybrid ablation for atrial fibrillation: a systematic review

PURPOSE

Hybrid ablation for AF is performed in a growing number of centers. Due to absence of guidelines, operative approaches and perioperative care differ per center. In this review, an overview of findings from published studies on hybrid ablations is given, and related topics are discussed (e.g., one- and two-stage approaches, lesion sets, and patient management).

METHODS

A systematic literature search was performed in the PubMed and Embase databases. All identified articles were screened and checked for eligibility by the two authors.

RESULTS

Twelve studies describing a total of 563 patients were selected. Due to substantial differences in approaches (one-stage, two-stage, sequential), surgical techniques (bilateral or monolateral thoracoscopy, subxiphoideal, transabdominal), energy sources (unipolar, bipolar), lesion sets (applying left or right atrial lesions), periprocedural care and endpoints (monitoring, definition of recurrence), and success rates (sinus rhythm after a mean of 26 months) are difficult to compare and varied from 27 % (without antiarrhythmic drugs, AADs) to 94 % (with AADs). For studies using bipolar devices, success rates with the use of antiarrhythmic drugs were at least 71 %. Major complications such as bleeding, sternotomy, and death occurred in 7 % of the total population (of which ten complications, 16 %, occurred in the concomitant cardiac surgery hybrid group).

CONCLUSION

The field of AF ablation has dramatically changed over the past years, with one of the most recent developments the hybrid AF ablation. Lack of matching data hinders drawing conclusions and creating guidelines. Early results however are encouraging. More data are awaiting and needed.