Pulmonary vein antrum isolation for treatment of atrial fibrillation in patients with valvular heart disease or prior open heart surgery

Catheter ablation for atrial fibrillation in hypertrophic cardiomyopathy patients: a systematic review

PURPOSE

The primary aim of this systematic review was to assess the efficacy of catheter ablation of atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM). Differentiation based off catheter ablation modalities was not considered due to the limited scope of the current field. Studies that employed alcohol septal ablation for the treatment of AF in HCM patients were excluded as were abstracts, case reports, conference presentations, editorials, reviews, and expert opinions

METHODS

Electronic searches were performed in six databases from their inception until January 2014. Relevant studies regarding catheter ablation for AF in HCM populations were identified. Data was extracted and analyzed according to pre-defined clinical endpoints

RESULTS

A review was undertaken of eight studies in which 241 HCM patients underwent catheter ablation for AF. Overall AF-free survival at last follow-up ranged from 47 to 77% (64-67%). Sinus rhythm was maintained at last follow-up in 47-82% (median 64-67%). AF recurrence ranged from 0 to 66% (median 35-40%).

CONCLUSION

A review of the current evidence suggests that catheter ablation of AF in HCM patients is effective with suitable efficacy and is justified in select patients. Future adequately powered randomized studies should be undertaken aimed at addressing long-term efficacy and complications associated with procedural outcomes.

Usefulness of left ventricular diastolic function to predict recurrence of atrial fibrillation in patients with preserved left ventricular systolic function

It is unknown whether recurrence of atrial fibrillation (AF) is related to severity of left ventricular diastolic dysfunction (LVDD) before ablation in patients with preserved left ventricular ejection fraction (LVEF). We tested the hypothesis that the presence and/or severity of LVDD before catheter ablation are related to AF recurrence during the 12-month follow-up period in patients with normal LVEF. We also aimed to determine what echocardiographic and Doppler indexes of LVDD before ablation are associated with recurrence of AF after ablation. We identified 198 patients with normal LVEF who underwent catheter ablation for AF with evidence of normal sinus rhythm within 1 year before ablation. The recurrence rate during 12-month follow-up period was assessed. Of the 198 patients, 76 patients (38%) had symptomatic recurrence and 122 patients (62%) had no recurrence. None of the independent variables, including mitral valve Doppler E and A peak velocities, E/A ratio, tissue Doppler e' and a' peak velocities, left atrial volume index, isovolumic relaxation time, and deceleration time, predicted recurrence. Patients with average E/e' ratio >13, however, had increased recurrence (67% vs 35%, odds ratio 3.70, 95% confidence interval 1.21 to 11.3, p <0.05). In conclusion, there was no difference in the severity of LVDD using conventional echocardiographic indexes of LVDD in patients with or without recurrence of AF ablation. However, patients with average E/e' ratio >13 did have an increased recurrence rate of AF at 12 months after procedure. Therefore, E/e' ratio, indicative of increased left atrial pressure, may serve as a marker for AF recurrence after ablation.

Percutaneous catheter ablation of atrial fibrillation

Atrial fibrillation is the most common arrhythmia and is associated with important morbidity and mortality. Antiarrhythmic therapy is recommended as initial therapy but is associated with modest efficacy and significant side effects. Over the past several years, catheter ablation has been demonstrated to provide effective and safe curative therapy for atrial fibrillation. Future investigations will assess advances in catheter ablation technology and will help to define the precise role of catheter ablation relative to alternative therapies, such as rate-control and antiarrhythmic therapy.

Effect of Remote Ischemic Preconditioning on Platelet Activation and Reactivity Induced by Ablation for Atrial Fibrillation

Background—

Radiofrequency ablation of atrial fibrillation has been associated with some risk of thromboembolic events. Previous studies showed that preventive short episodes of forearm ischemia (remote ischemic preconditioning [IPC]) reduce exercise-induced platelet reactivity. In this study, we assessed whether remote IPC has any effect on platelet activation induced by radiofrequency ablation of atrial fibrillation.

Methods and Results—

We randomized 19 patients (age, 54.7±11 years; 17 male) undergoing radiofrequency catheter ablation of paroxysmal atrial fibrillation to receive remote IPC or sham intermittent forearm ischemia (control subjects) before the procedure. Blood venous samples were collected before and after remote IPC/sham ischemia, at the end of the ablation procedure, and 24 hours later. Platelet activation and reactivity were assessed by flow cytometry by measuring monocyte-platelet aggregate formation, platelet CD41 in the monocyte-platelet aggregate gate, and platelet CD41 and CD62 in the platelet gate in the absence and presence of ADP stimulation. At baseline, there were no differences between groups in platelet variables. Radiofrequency ablation induced platelet activation in both groups, which persisted after 24 hours. However, compared with control subjects, remote IPC patients showed a lower increase in all platelet variables, including monocyte-platelet aggregate formation ( P <0.0001), CD41 in the monocyte-platelet aggregate gate ( P =0.002), and CD41 ( P <0.0001) and CD62 ( P =0.002) in the platelet gate. Compared with control subjects, remote IPC was also associated with a significantly lower ADP-induced increase in all platelet markers.

Conclusions—

Our data show that remote IPC before radiofrequency catheter ablation for paroxysmal atrial fibrillation significantly reduces the increased platelet activation and reactivity associated with the procedure.

Surgical treatment of lone atrial fibrillation

Currently, off-pump video-assisted thoracoscopic epicardial pulmonary vein isolation offers an attractive alternative to on-pump Maze procedures for surgical treatment of lone atrial fibrillation. Nevertheless, on-pump Maze procedures through a mid-sternotomy approach still play an important role in patients with lone atrial fibrillation on many occasions, especially in patients with failed percutaneous pulmonary vein alone. The aim of this article was to give a brief review of the surgical strategies for treating lone atrial fibrillation, and present the possible indications for on-pump Maze procedures through a mid-sternotomy approach.

Long-term results of catheter ablation in paroxysmal atrial fibrillation: lessons from a 5-year follow-up

BACKGROUND

Paroxysmal atrial fibrillation (AF) naturally progresses toward chronic AF at an estimated rate of 15% to 30% over a 1- to 3-year period. Pulmonary vein (PV) isolation is increasingly performed for the treatment of drug-refractory paroxysmal AF. The long-term data on clinical outcome after circumferential PV isolation are limited.

METHODS AND RESULTS

From 2003 to late 2004, 161 patients (121 men; age, 59.8±9.7 years) with symptomatic paroxysmal AF and normal left ventricular function underwent circumferential PV isolation guided by 3-dimensional mapping and double Lasso technique. Right-sided and left-sided continuous circular lesions encircling the ipsilateral PVs were placed with irrigated radiofrequency energy. The procedure end point was the absence of all PV spikes for at least 30 minutes after PV isolation verified by 2 Lasso catheters placed within the ipsilateral PVs. Sinus rhythm was present in 75 patients (46.6%) after the initial procedure during a median follow-up period of 4.8 years (0.33 to 5.5 years). A second procedure was performed in 66 and a third procedure in 12 patients. Recovered PV isolation conduction was observed in 62 of 66 patients (94.0%) during the second and in 8 of 12 patients (66.7%) during the third procedure. After a median of 1 (1 to 3) procedure, stable sinus rhythm was achieved in 128 of 161 patients (79.5%), whereas clinical improvement occurred in an additional 21 of 161 patients (13.0%) during a median follow-up of 4.6 years (0.33 to 5.5 years). Four patients in stable sinus rhythm died during follow-up. Progression toward chronic AF was observed in 4 patients (2.4%); however, only 2 patients reported symptoms.

CONCLUSION

In patients with paroxysmal AF and normal left ventricular function, circumferential PV isolation results in stable sinus rhythm in the majority of patients, and low incidence of chronic AF was observed after ablation during up to 5 years of follow-up.

Atrial flutter versus atrial fibrillation in a general population: differences in comorbidities associated with their respective onset

OBJECTIVE

Determine and compare the prevalence of known risk factors for cardiovascular disease among unselected individuals presenting with their first ever episode of atrial flutter (AFL) and atrial fibrillation (AF).

STUDY DESIGN AND SETTING

We evaluated 11 pre-selected clinical variables including age, sex, smoking history and other potential cardiac risk factors. Using the resources of the Marshfield Epidemiologic Study Area, a population-based database, all newly diagnosed cases of either AFL or AF in the region during a 4-year period were identified.

RESULTS

Among the 472 incident cases, 76 (16.1%) had AFL and 396 (83.9%) had AF. Compared to those with AF, subjects with AFL were more likely to have had a history of chronic obstructive pulmonary disease (25% vs. 12%, P = 0.006), heart failure (28% vs. 17%, P = 0.05), and smoking (49% vs. 37%, P = 0.06). Hypertension, on the other hand, was more common among individuals with AF (63% vs. 47%, P = 0.01).

CONCLUSION

This study represents the first report to evaluate potential differences in the conditions associated with the development of AFL versus AF. Research into the mechanisms of atrial arrhythmogenesis may lead to improved preventive and therapeutic interventions.

Effectiveness of catheter ablation versus antiarrhythmic drug therapy for atrial fibrillation

PURPOSE OF REVIEW

The optimal treatments for atrial fibrillation have long been sought among rhythm control and rate control strategies. Unfortunately, rhythm control strategies with antiarrhythmic drugs have proven to be a disappointment. Catheter ablation techniques, however, have been rapidly advancing and have the potential to offer a permanent cure. Rhythm control with catheter ablation may in fact be a superior treatment modality for atrial fibrillation. The purpose of this review is to examine the evidence in favor of this argument.

RECENT FINDINGS

The dissatisfaction with poorly performing antiarrhythmic drug therapies for the treatment of atrial fibrillation has fueled the development of alternative therapies for rhythm control. Catheter ablation has emerged as a viable, efficacious, and safe alternative. In fact, in head to head comparisons with antiarrhythmic drugs, catheter ablation continues to come out on top with often markedly superior performances. In addition to efficacy and safety, catheter ablation also seems to be a fiscally viable alternative.

SUMMARY

On the basis of the outstanding performance of catheter ablation compared with antiarrhythmic drug therapy, it is not surprising to see its widespread adoption and ever expanding indications.

High sensitivity of the sheep pulmonary vein antrum to acetylcholine stimulation

Isolation of the pulmonary vein antrum can terminate atrial fibrillation, but the rationale has not been elucidated. In the present study, we show that sheep atrial effective refractory period (ERP) was heterogeneously shortened by acetylcholine administration. After perfusion with 15 μM acetylcholine, the shortest ERP occurred in the pulmonary vein antrum, which was recorded with the standard intracellular microelectrode technique (the ERP results in the pulmonary vein antrum, left atrial posterior wall, roof, free wall and appendage, and right atrial free wall were 52.0 ± 1.6, 75.1 ± 2.0, 77.2 ± 1.7, 85.6 ± 1.7, 64.3 ± 2.1, and 90.5 ± 1.3 ms, respectively; P < 0.05). Immunofluorescent staining revealed that muscarinic type 2 receptors (M2R) were also distributed heterogeneously in the atrial myocardium, with the highest density in the antrum (the relative fluorescent intensity results of the M2R in the pulmonary vein antrum, left atrial posterior wall, roof, free wall and appendage, and right atrial free wall were 62.64 ± 2.56, 53.12 ± 2.76, 51.83 ± 2.45, 47.90 ± 2.33, 55.27 ± 2.08, and 45.53 ± 2.02, respectively; P < 0.05), which was in accordance with the heterogeneity of ERP distribution. Thus the pulmonary vein antrum is a unique electrophysiological region with high sensitivity to acetylcholine, and its intensive response to acetylcholine is most likely associated with the dense M2R distribution of this region. Such an acetylcholine-induced ERP heterogeneity is possibly a substrate for atrial fibrillation and hence one of the potential electrophysiological bases for the isolation therapy.

MDCT of the S-shaped sinoatrial node artery

OBJECTIVE

The purpose of this study was to use 64-MDCT to investigate the anatomic characteristics of the S-shaped variant of the sinoatrial node (SAN) artery and to describe the clinical implications of the findings in ablative procedures involving the left atrium.

MATERIALS AND METHODS

Coronary CT angiograms of 250 patients (152 men, 98 women; mean age, 60 +/- 12 [SD] years) were retrospectively analyzed for identification of the origin, number, anatomic course, mode of termination, and S-shaped variant of the SAN artery.

RESULTS

At least one SAN artery was detected in 244 patients. The S-shaped variant was seen in 35 (14.3%) of these patients. Thirty-four of the variants (30.6% of all left SAN arteries) arose from the proximal to middle portion of the left circumflex artery (mean distance between the ostium of the left circumflex artery and the origin of S-shaped variant, 28.7 +/- 13.1 mm). The other variant (0.7% of all right SAN arteries) originated from the distal right coronary artery. The S-shaped variant was the only artery supplying the SAN in 28 (11.4%) of the patients. In patients with two arteries supplying the SAN, the right SAN artery and the S-shaped variant of the left SAN artery were seen together in seven patients. The S-shaped SAN artery (mean distance from atrial wall, 2.43 +/- 0.992 mm) had a predictable proximal course, lying in the posterior aspect in a groove between the orifices of the left superior pulmonary vein and the left atrial appendage close to the left atrial wall. The terminal segment of the artery approached the nodal tissue posterior to the superior vena cava in 22 patients, anterior to the vena cava in 10 patients, and through branches surrounding the vena cava in two patients.

CONCLUSION

The S-shaped variation of the SAN artery is common and has a characteristic anatomic course. MDCT can be used to plan surgical and catheter-based left atrial interventions in which this artery is at risk of injury.

Cost Comparison of Catheter Ablation and Medical Therapy in Atrial Fibrillation

INTRODUCTION

There is emerging evidence for clinical superiority of catheter ablation over rate and rhythm control strategies in paroxysmal atrial fibrillation (PAF). The objective of this study was to compare costs related to medical therapy versus catheter ablation for PAF in Ontario (Canada).

METHODS

Costs related to medical therapy in the analysis included the cost of anticoagulation, rate and rhythm control medications, noninvasive testing, physician follow-up visits, and hospital admissions, as well as the cost of complications related to this management strategy. Costs related to catheter ablation were assumed to include the cost of the ablation tools (electroanatomic mapping or intracardiac echocardiography-guided pulmonary vein ablation), hospital and physician billings, and costs related to periprocedural medical care and complications. Costs related to these various elements were obtained from the Canadian Registry of Atrial Fibrillation (CARAF), government fee schedules, and published data. Sensitivity analyses looking at a range of initial success rates (50-75%) and late attrition rates (1-5%), prevalence of congestive heart failure (CHF) (20-60%), as well as discounting varying from 3% to 5% per year were performed.

RESULTS

The cost of catheter ablation ranged from $16,278 to $21,294, with an annual cost of $1,597 to $2,132. The annual cost of medical therapy ranged from $4,176 to $5,060. Costs of ongoing medical therapy and catheter ablation for PAF equalized at 3.2-8.4 years of follow-up.

CONCLUSION

Catheter ablation is a fiscally sensible alternative to medical therapy in PAF with cost equivalence after 4 years.

Ten-year Experience With the Cox-Maze Procedure for Atrial Fibrillation: How Do We Define Success?

BACKGROUND

The Cox-maze procedure is the standard to which other surgical treatments of atrial fibrillation (AF) are compared. However, evaluation of new devices and lesion sets is difficult because of variable methods of reporting success in eliminating AF. We analyzed 10-year outcome with the "cut and sew" Cox-maze procedure and present rhythm at last follow-up, interval contact, and actuarial AF freedom.

METHODS

Between March 1993 and December 2002, 335 patients (211 men) underwent the Cox-maze procedure (age, 22 to 83 years; median, 62 years). Atrial fibrillation was chronic (CAF) in 175 patients and paroxysmal (PAF) in 160.

RESULTS

Concomitant mitral valve procedures were performed in 59%, coronary artery bypass grafting in 19%, and tricuspid valve repairs in 7%. Early mortality was 0.9%. During hospitalization, transient AF occurred in 29% of patients and 10% required implantation of a new permanent pacemaker (PPM). Dismissal electrocardiogram was normal sinus rhythm in 64%, junctional rhythm in 18%, AF in 11%, and PPM in 7%. At last follow-up (mean 42 +/- 6 months), 88% of patients were free of AF. However, when analyzed by the Kaplan-Meier method, freedom from AF was lower for patients with preoperative lone PAF (5 years, 90%; 10 years, 64%), preoperative lone CAF (5 years, 80%; 10 years, 62%), and patients undergoing combined maze-mitral valve surgery (5 years, 68%; 10 years, 41%).

CONCLUSIONS

Ten-year results with the standard Cox-maze procedure confirm high effectiveness, but reporting methods should be standardized to account for patients who have transient atrial arrhythmias during long-term follow-up.

Catheter Ablation Therapy for Atrial Fibrillation Current Advancements in Strategies

Curing atrial fibrillation (AF) by catheter ablation has significantly improved patient morbidity and mortality. The circumferential pulmonary vein isolation technique is established as the principal procedure, with a high cure rate and acceptable safety, for paroxysmal AF, but new adjunctive ablation strategies targeting the AF substrates and sources for long-standing persistent/chronic AF have been developed. These new techniques include linear ablation, complex fractionated atrial electrogram guided ablation, dominant frequency map-guided ablation, ganglionated plexi ablation and disconnection of the coronary sinus and superior vena cava to ablate the AF substrates and sources. The long-term usefulness of the established technique and these innovative adjunctive approaches for the treatment of AF remains to be investigated.

Cost-effectiveness of catheter ablation for atrial fibrillation

PURPOSE OF REVIEW

Catheter ablation for atrial fibrillation is a rapidly evolving field. It has been adopted at many institutions worldwide. This review compares the efficacy and cost of catheter ablation and medical therapy in atrial fibrillation patients.

RECENT FINDINGS

There is emerging evidence for clinical superiority of catheter ablation over medical therapy for restoring and maintaining sinus rhythm in atrial fibrillation patients. Early analyses of costs related to catheter ablation in atrial fibrillation suggest that medical therapy and catheter ablation become cost-equivalent at about 5 years of follow-up. A recent cost-effectiveness study concluded that catheter ablation is a cost-effective alternative to medical care in younger and older patients at low and moderate risk of stroke, assuming that restoration and maintenance of sinus rhythm with ablation would have some protective effect with respect to embolic events.

SUMMARY

Catheter ablation is a potentially cost-effective strategy in select patients with atrial fibrillation. Long-term randomized studies that compare it to conventional care and focus on outcomes of morbidity and mortality are necessary prior to widespread application of this technique.

A Single Pulmonary Vein as Electrophysiological Substrate of Paroxysmal Atrial Fibrillation

INTRODUCTION

It has been demonstrated that pulmonary veins (PVs) play an important role in initiation and maintenance of paroxysmal atrial fibrillation (AF). However, it is not clearly known whether a single PV acts as electrophysiological substrate for paroxysmal AF.

METHODS AND RESULTS

This study included five patients with paroxysmal AF. All patients underwent complete PV isolation with continuous circular lesions (CCLs) around the ipsilateral PVs guided by a three-dimensional mapping system. Irrigated radiofrequency (RF) delivery was performed during AF on the right-sided CCLs in two patients and on the left-sided CCLs in three patients. The incomplete CCLs resulted in a change from AF to atrial tachycardia (AT), which presented with an identical atrial activation sequence and P wave morphology. Complete CCLs resulted in AF termination with persistent PV tachyarrhythmias within the isolated PV in all five patients. PV tachyarrhythmia within the isolated PV was PV fibrillation from the left common PV (LCPV) in two patients, PV tachycardia from the right superior PV (RSPV) in two patients, and from the left superior PV in one patient. All sustained PV tachyarrhythmias persisted for more than 30 minutes, needed external cardioversion for termination in four patients and a focal ablation in one patient. After the initial procedure, an AT from the RSPV occurred in a patient with PV fibrillation within the LCPV, and was successfully ablated.

CONCLUSION

In patients with paroxysmal AF, sustained PV tachyarrhythmias from a single PV can perpetuate AF. Complete isolation of all PV may provide good clinical outcome during long-term follow-up.

Incidence of Atrial Fibrillation in Heart Transplant Patients: Long-Term Follow-Up

BACKGROUND

The incidence of atrial fibrillation (AF) in heart transplant patients has not been well documented.

METHODS

To determine the incidence of AF in a cohort of patients undergoing cardiac transplantation, clinical data were obtained from a prospectively collected database for all consecutive orthotopic heart transplantation (OHT) patients and for all consecutive coronary artery bypass graft (CABG) surgery patients between January 1984 and March 2004 at our institution. A cohort of 1,714 OHT patients and low-risk CABG (normal ejection fraction [EF] and no left ventricular hypertrophy [LVH]) patients were age- and sex-matched.

RESULTS

The average age in the two groups was 56 +/- 7 years with 87% male and 81% white race and body mass index (BMI) of 26 +/- 4. There were 3 cases of AF (0.3%) in the OHT group and 757 cases of AF (21%) in the low-risk CABG group. The strongest independent predictor of freedom from postoperative AF was having had a transplant (odds ratio [OR] 96, 95% confidence interval [CI] 13-720). The incidence of AF, atrial flutter (AFL), and supraventricular tachycardia (SVT) in OHT was 0.33, 2.8%, and 1.3%, respectively. Given that incidence of AF, AFL, and SVT in historical post-CABG population is 25%, 17%, and 4.3%, transplanted patients appear to have lower incidence of AF, AFL, and SVT than the reference population. Consistent with this, transplanted patients underwent few ablation procedures for atrial arrhythmias. Additionally, the three patients with AF had bicaval anastomoses suggesting the possibility of PACs originating in the donor superior vena cava (SVC) or IVC (inferior vena cava) initiating AF in these patients.

CONCLUSIONS

In a cohort study of transplant and low-risk CABG patients, the strongest independent predictor of freedom from AF is having undergone transplant surgery. One potential explanation for the markedly lower incidence of AF may be effective isolation of thoracic veins with documented cases retaining the native SVC.

Transcranial Doppler Detection of Microembolic Signals During Pulmonary Vein Antrum Isolation: Implications for Titration of Radiofrequency Energy

BACKGROUND

Cerebrovascular events are an important complication during pulmonary vein antrum isolation (PVAI). Microembolic signals (MES) have been associated with stroke and neurological impairment. However, the incidence of MES during PVAI, and their relationship to microbubble formation and radiofrequency (RF) parameters are unknown.

OBJECTIVES

We sought to assess the relationship between MES, microbubble detection, and neurological outcome and the impact of RF titration strategy on these parameters.

METHODS

We studied 202 patients in two groups undergoing PVAI using an intracardiac echocardiography (ICE)-guided technique. MES were detected by transcranial Doppler (TCD) using insonation of the middle cerebral arteries. The number of microbubbles on ICE were qualitatively labeled as FEW, MODERATE, and SHOWER. In group I (n = 107), RF output was titrated to avoid microbubble formation and in group II (n = 95), standard power-limited RF output was used.

RESULTS

TCD detected MES in all 202 patients during PVAI with an average of 1,793 +/- 547 per patient; 90% were detected during left atrial ablation. Over 85% of MES occurred after microbubbles. Group I patients had significantly lower numbers of MES (1,015 +/- 438 per patient) compared to group II patients (2,250 +/- 864 per patient) (P < 0.05). Group II also had a 3.1% incidence of acute neurological complications versus 0.9% in group I (P = 0.10). Patients with clinical events had significantly higher numbers of MES. There were no significant correlations between RF power, temperature, or impedence and MES number.

CONCLUSIONS

MES directly correlate to the amount of microbubble formation on ICE, and may result in cerebroembolic complications. Titration of RF according to microbubble formation by ICE during PVAI may be important for minimizing the occurrence of MES and possibly acute neurological complications.

Ablation of Atrial Fibrillation

Due in large part to the growing dissatisfaction with traditional pharmacologic approaches to atrial fibrillation (AF) management, and fueled by both the fruits of basic and clinical investigation into the nature of AF initiation and maintenance and the explosive development in catheter-based technologies, AF ablation has matured from a purely investigational technique to a viable--and often preferred--strategy for treating patients suffering from this arrhythmia. Future insights and developments will help us refine our treatment strategies, making AF ablation safer, faster, and more effective. As the prevalence of AF in the general population continues to expand, the goal of optimizing our approach to AF becomes ever more important--and more pressing.

Atrial Fibrillation Ablation: Reaching the Mainstream

INTRODUCTION AND AIMS

Ablation of atrial fibrillation (AF) has evolved rapidly in the decade since its inception. We aimed to review the results of this evolution as reflected in the published literature.

METHODS

Publications through 2005 were reviewed, and data included if there was information on the technique used, and follow-up of at least 6 months.

RESULTS

More than 23,000 patients met criteria for inclusion. There has been a steady improvement in reported outcomes (P<0.001). Variations on radiofrequency catheter ablation for pulmonary vein isolation result in apparent elimination ("cure") or improvement of AF in 75%, and surgical techniques are even better.

CONCLUSIONS

Catheter ablation of AF is now a mainstream procedure. Continuing technical advances are needed to achieve better results with more uniformity and reduced procedure times.

Efficacy of catheter ablation of atrial fibrillation in patients with hypertrophic obstructive cardiomyopathy

BACKGROUND

Although pulmonary vein (PV) antrum isolation is effective in curing atrial fibrillation (AF) in a variety of heart diseases, results in patients with hypertrophic obstructive cardiomyopathy (HOCM) have not been reported.

OBJECTIVES

The purpose of this study was to report the results and outcome of PV antrum isolation in patients with AF and HOCM.

METHODS

Data from patients with AF and HOCM who underwent PV antrum isolation between February 2002 and May 2004 were analyzed retrospectively. An intracardiac echocardiographic-guided ablation technique with an 8-mm-tip catheter was used in all patients. Patients were followed in the outpatient clinic at 3, 6, and 12 months after ablation.

RESULTS

Twenty-seven patients with AF and HOCM (mean age 55 +/- 10 years) underwent PV antrum isolation. Mean AF duration was 5.4 +/- 3.6 years. AF was paroxysmal in 14 (52%), persistent in 9 (33%), and permanent in 4 (15%). During a mean follow-up of 341 +/- 237 days, 13 patients (48%) had AF recurrence. Of these patients, five maintained sinus rhythm (SR) with antiarrhythmic drugs, one patient remained in persistent AF, and seven patients underwent a second PV antrum isolation. After the second PV antrum isolation, five patients remained in SR, giving a final success rate of 70% (19/27). Two patients had recurrence after second PV antrum isolation; one maintained SR with antiarrhythmic drugs and one remained in persistent AF.

CONCLUSION

Compared with previously reported results in patients with lone AF, AF recurrence after the first PV antrum isolation is higher in patients with HOCM. However, after repeated ablation procedures, long-term cure can be achieved in a sizable number of patients. PV antrum isolation is a feasible therapeutic option in patients with AF and HOCM.

Surgery for Paroxysmal Atrial Fibrillation in the Setting of Mitral Valve Disease: A Role for Pulmonary Vein Isolation?

BACKGROUND

It is unknown whether pulmonary vein isolation or a complete Cox-Maze procedure is needed to ablate paroxysmal atrial fibrillation in patients with mitral valve disease. Our objective was to assess the impact of different surgical treatments for this arrhythmia in patients undergoing mitral valve surgery.

METHODS

From July 1993 to January 2004, 152 patients underwent combined surgical treatment of paroxysmal atrial fibrillation and mitral valve disease. Ablation procedures included pulmonary vein isolation alone (n = 31, 20%), pulmonary vein isolation with left atrial connecting lesions (n = 80, 53%), and Cox-Maze (n = 41, 27%). The latter had longer durations of atrial fibrillation than the former (p < 0.0001). Rhythm documented on 1,225 postoperative electrocardiograms was used to estimate prevalence of, and risk factors for, atrial fibrillation across time. Ablation failure was defined as occurrence of atrial fibrillation any time beyond 6 months after operation.

RESULTS

Prevalence of postoperative atrial fibrillation peaked at 22% at 2 weeks and declined to 9% at 1 year. Risk factors included older age (p = 0.09), larger left atrium (p = 0.05), and rheumatic (p = 0.003) and degenerative etiologies (p = 0.03). Freedom from ablation failure was 84% at one year. Ablation procedure did not affect prevalence of atrial fibrillation or incidence of ablation failure.

CONCLUSIONS

Pulmonary vein isolation alone may be adequate treatment for patients with paroxysmal atrial fibrillation undergoing mitral valve surgery, particularly when it is of short duration. A randomized trial is necessary to examine this strategy, especially in patients with longer duration of paroxysmal atrial fibrillation.

Electrophysiological findings during ablation of persistent atrial fibrillation with electroanatomic mapping and double Lasso catheter technique

BACKGROUND

Pulmonary veins (PVs) can be completely isolated with continuous circular lesions (CCLs) around the ipsilateral PVs. However, electrophysiological findings have not been described in detail during ablation of persistent atrial fibrillation (AF).

METHODS AND RESULTS

Forty patients with symptomatic persistent AF underwent complete isolation of the right-sided and left-sided ipsilateral PVs guided by 3D mapping and double Lasso technique during AF. Irrigated ablation was initially performed in the right-sided CCLs and subsequently in the left-sided CCLs. After complete isolation of both lateral PVs, stable sinus rhythm was achieved after AF termination in 12 patients; AF persisted and required cardioversion in 18 patients. In the remaining 10 patients, AF changed to left macroreentrant atrial tachycardia in 6 and common-type atrial flutter in 4 patients. All atrial tachycardias were successfully terminated during the procedure. Atrial tachyarrhythmias recurred in 15 of 40 patients at a median of 4 days after the initial ablation. A repeat ablation was performed at a median of 35 days after the initial procedure in 14 patients. During the repeat study, recovered PV conduction was found in 13 patients and successfully abolished by focal ablation of the conduction gap of the previous CCLs. After a mean of 8+/-2 months of follow-up, 38 (95%) of the 40 patients were free of AF.

CONCLUSIONS

In patients with persistent AF, CCLs can result in either AF termination or conversion to macroreentrant atrial tachycardia in 55% of the patients. In addition, recovered PV conduction after the initial procedure is a dominant finding in recurrent atrial tachyarrhythmias and can be successfully abolished.

Anatomic substrate, procedural results, and clinical outcome of ultrasound-guided left atrial-pulmonary vein disconnection for treatment of atrial fibrillation

This report summarizes the efficacy, safety, and feasibility of intracardiac ultrasound (ICUS) and local electrographic-guided pulmonary vein (PV)-left atrial disconnection, including the isolation of common PV trunks accomplished in 170 consecutive patients with atrial fibrillation (AF). A left common PV was found in 43% of patients with AF. During a follow-up of 549 +/- 330 days after ablation, the AF-free survival rate was 80% and comparable in paroxysmal and persistent AF. PV stenosis was detected in only 1 asymptomatic patient, who required no intervention.

The need for atrial flutter ablation following pulmonary vein antrum isolation in patients with and without previous cardiac surgery

OBJECTIVES

The aim of this study was to assess the incidence of atrial flutter (AFL) after pulmonary vein antrum isolation (PVAI) in patients with previous cardiac surgery (PCS) in comparison to patients without PCS and to assess the need for AFL ablation in both groups.

BACKGROUND

Atrial fibrillation (AF) and AFL often co-exist. Pulmonary vein antrum isolation may be sufficient to control both arrhythmias. However, in patients with PCS, atrial incisions, cannulations, and scar areas may cause AFL recurrence despite elimination of pulmonary vein triggers.

METHODS

Data from 1,345 patients who had PVAI were analyzed. Patients with a history of AFL ablation and patients who had concomitant AFL ablation during PVAI were excluded from analysis. Sixty-three patients constituted the PCS group (Group 1, age 57 +/- 13 years, 12 female) and 1,062 patients constituted the non-PCS group (Group 2, age 55 +/- 12 years, 212 female). Patients in Group 1 had larger left atria, higher incidence of AFL pre-PVAI, and lower ejection fraction.

RESULTS

There was no significant difference in post-PVAI AF recurrence between Groups 1 and 2, but AFL incidence after PVAI was higher in Group 1 (33% vs. 4%, p < 0.0001). Ablation of AFL in Group 1 patients resulted in an 86% acute success rate and 11% recurrence over a mean follow-up of 357 +/- 201 days.

CONCLUSIONS

In patients with PCS, post-PVAI AF recurrence is similar to patients without PCS. However, history of PCS is associated with a higher recurrence of AFL after PVAI. In a significant number of patients with PCS, AFL ablation is required to achieve a cure.

A New Nonfluoroscopic Navigation System to Guide Pulmonary Vein Isolation

Different techniques have been proposed to treat atrial fibrillation (AF) by catheter ablation. This study compares a new three-dimensional (3D) nonfluoroscopic navigation system with conventional fluoroscopy to guide pulmonary vein (PV) isolation. A total of 60 consecutive patients with paroxysmal or persistent AF were randomly assigned to 3D-guided ablation (group 1, n = 30), versus conventional fluoroscopy guidance ablation (group 2, n = 30). Complete PV isolation was achieved in both groups. The mean duration of fluoroscopy exposure (22 +/- 8 vs 56 +/- 10 minutes), and radiofrequency delivery (5 +/- 1 vs 10 +/- 3 minutes) were significantly shorter in group 1 than in group 2, P < 0.05 for both comparisons). The mean procedural time in group 1 was longer (225 +/- 15 minutes) than in group 2 (156 +/- 10 minutes, P < 0.05) due to the learning curve and time spent to generate the 3D maps. Over a mean follow-up of 7 +/- 2 months, 6 patients (20%) in group 2 had AF recurrences compared to 3 patients (10%) in group 1 (ns). The new nonfluoroscopic 3D system allows a high-resolution reconstruction of the left atrium and PVs. It significantly reduces the mean radiofrequency delivery and fluoroscopy times as opposed to ablation performed under fluoroscopy guidance.

Pre-existent left atrial scarring in patients undergoing pulmonary vein antrum isolation

OBJECTIVES

The goal of this study was to assess the impact of left atrial scarring (LAS) on the outcome of patients undergoing pulmonary vein antrum isolation (PVAI) for atrial fibrillation (AF).

BACKGROUND

Left atrial scarring may be responsible for both the perpetuation and genesis of AF.

METHODS

A total of 700 consecutive patients undergoing first-time PVAI were studied. Before ablation, extensive voltage mapping of the left atrium (LA) was performed using a multipolar Lasso catheter guided by intracardiac echocardiography (ICE). Patients with LAS were defined by a complete absence of electrographic recording by a circular mapping catheter in multiple LA locations, and this was validated by electroanatomic mapping. All four pulmonary vein antra and the superior vena cava were isolated using an ICE-guided technique. Patients were followed at least nine months for late AF recurrence. Univariate and multivariate analyses were performed to assess the predictive value of LAS and other variables on outcome.

RESULTS

Of 700 patients, 42 had LAS, which represented 21 +/- 11% of the LA surface area by electroanatomic mapping. Patients with LAS had a significantly higher AF recurrence (57%) compared with non-LAS patients (19%, p = 0.003). Also, LAS was associated with a significantly larger LA size, lower ejection fraction, and higher C-reactive protein levels. Univariate analysis revealed age, nonparoxysmal AF, and LAS as predictors of recurrence. Multivariate analysis showed LAS as the only independent predictor of recurrence (hazard ratio 3.4, 95% confidence interval 1.3 to 9.4; p = 0.01).

CONCLUSIONS

Pre-existent LAS in patients undergoing PVAI for AF is a powerful, independent predictor of procedural failure. Left atrial scarring is associated with a lower EF, larger LA size, and increased inflammatory markers.