Marcin Kowalski

In-Hospital Complications Associated With Catheter Ablation of Atrial Fibrillation in the United States Between 2000 and 2010 Analysis of 93 801 Procedures

Background— Atrial fibrillation ablation has made tremendous progress with respect to innovation, efficacy, and safety. However, limited data exist regarding the burden and trends in adverse outcomes arising from this procedure. The aim of our study was to examine the frequency of adverse events attributable to atrial fibrillation (AF) ablation and the influence of operator and hospital volume on outcomes. Methods and Results— With the use of the Nationwide Inpatient Sample, we identified AF patients treated with catheter ablation. We investigated common complications including cardiac perforation and tamponade, pneumothorax, stroke, transient ischemic attack, vascular access complications (hemorrhage/hematoma, vascular complications requiring surgical repair, and accidental arterial puncture), and in-hospital death described with AF ablation, and we defined these complications by using validated International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes. An estimated 93 801 AF ablations were performed from 2000 to 2010. The overall frequency of complications was 6.29% with combined cardiac complications (2.54%) being the most frequent. Cardiac complications were followed by vascular complications (1.53%), respiratory complications (1.3%), and neurological complications (1.02%). The in-hospital mortality was 0.46%. Annual operator (<25 procedures) and hospital volume (<50 procedures) were significantly associated with adverse outcomes. There was a small (nonsignificant) rise in overall complication rates. Conclusions— The overall complication rate was 6.29% in patients undergoing AF ablation. There was a significant association between operator and hospital volume and adverse outcomes. This suggests a need for future research into identifying the safety measures in AF ablations and instituting appropriate interventions to improve overall AF ablation outcomes.

Contemporary Trends of Hospitalization for Atrial Fibrillation in the United States, 2000 Through 2010 Implications for Healthcare Planning

Background— Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. The associated morbidity and mortality make AF a major public health burden. Hospitalizations account for the majority of the economic cost burden associated with AF. The main objective of this study is to examine the trends of AF-related hospitalizations in the United States and to compare patient characteristics, outcomes, and comorbid diagnoses. Methods and Results— With the use of the Nationwide Inpatient Sample from 2000 through 2010, we identified AF-related hospitalizations using International Classification of Diseases, 9th Revision, Clinical Modification code 427.31 as the principal discharge diagnosis. Overall AF hospitalizations increased by 23% from 2000 to 2010, particularly in patients ≥65 years of age. The most frequent coexisting conditions were hypertension (60.0%), diabetes mellitus (21.5%), and chronic pulmonary disease (20.0%). Overall in-hospital mortality was 1%. The mortality rate was highest in the group of patients ≥80 years of age (1.9%) and in the group of patients with concomitant heart failure (8.2%). In-hospital mortality rate decreased significantly from 1.2% in 2000 to 0.9% in 2010 (29.2% decrease; P<0.001). Although there was no significant change in mean length of stay, mean cost of AF hospitalization increased significantly from

Histopathologic characterization of chronic radiofrequency ablation lesions for pulmonary vein isolation.

6410 in 2001 to

Results of a Minimally Invasive Surgical Pulmonary Vein Isolation and Ganglionic Plexi Ablation for Atrial Fibrillation Single-Center Experience With 12-Month Follow-Up

8439 in 2010 (24.0% increase; P<0.001). Conclusions— Hospitalization rates for AF have increased exponentially among US adults from 2000 to 2010. The proportion of comorbid chronic diseases has also increased significantly. The last decade has witnessed an overall decline in hospital mortality; however, the hospitalization cost has significantly increased.

Best practice guide for cryoballoon ablation in atrial fibrillation: The compilation experience of more than 3000 procedures.

OBJECTIVES This study describes the histopathologic and electrophysiological findings in patients with recurrence of atrial fibrillation (AF) after pulmonary vein (PV) isolation who underwent a subsequent surgical maze procedure. BACKGROUND The recovery of PV conduction is commonly responsible for recurrence of AF after catheter-based PV isolation. METHODS Twelve patients with recurrent AF after acutely successful catheter-based antral PV isolation underwent a surgical maze procedure. Full-thickness surgical biopsy specimens were obtained from the PV antrum in areas of visible endocardial scar. Before biopsy, intraoperative epicardial electrophysiological recordings were taken from each PV using a circular mapping catheter. RESULTS Twenty-two PVs were biopsied from the 12 patients 8 ± 11 months after ablation. Eleven of the 22 specimens (50%) revealed transmural scar, and 11 (50%) showed viable myocardium with or without scar. Each biopsy specimen demonstrated evidence of injury, most commonly endocardial thickening (n = 21 [95%]) and fibrous scar (n = 18 [82%]). Seven of the 22 specimens (32%) showed conduction block at surgery. Transmural scar was more likely to be seen in the biopsy specimens from the PVs with conduction block than in specimens from the PVs showing reconnection. However, viable myocardium alone or mixed with scar was seen in 2 specimens from PVs with conduction block. CONCLUSIONS PVs showing electrical reconnection after catheter-based antral ablation frequently reveal anatomic gaps or nontransmural lesions at the sites of catheter ablation. Nontransmural lesions are noted in some PVs with persistent conduction block, suggesting that lesion geometry may influence PV conduction. The histological findings show that nontransmural ablation can produce a dynamic cellular substrate with features of reversible injury. Delayed recovery from injury may explain late recurrences of AF after PV isolation.

Acute and Long‐Term Outcomes of Catheter Ablation of Atrial Fibrillation Using the Second‐Generation Cryoballoon versus Open‐Irrigated Radiofrequency: A Multicenter Experience

Background—The Cox Maze procedure for treatment of medically refractory atrial fibrillation (AF) is limited by its complexity and requirement for cardiopulmonary bypass. Long-term follow-up and success using criteria established by the Heart Rhythm Society/European Heart Rhythm Association/European Cardiac Arrhythmia Society consensus statement have not been reported for surgical AF ablation. We describe the results of using a thorascopic approach and radiofrequency energy to perform bilateral pulmonary vein isolation and left atrial ganglionic plexi ablation for treatment of AF. Methods and Results—Forty-five (33 paroxysmal; 12 persistent) consecutive patients underwent thorascopic bilateral radiofrequency pulmonary vein isolation, ganglionic plexi ablation, ligament of Marshall ablation, and left atrial appendage exclusion by a single surgeon. Forty-three patients were prospectively followed without antiarrhythmic drugs for a minimum of 1 year with a 30-day continuous event monitor or pacemaker interrogation at 6 and 12 months. Failure was defined as any atrial tachyarrhythmia of >30 seconds’ duration occurring >90 days after surgery. Mean follow-up was 516±181 days (202 to 858 days). Twenty-eight (65%) patients had no atrial tachyarrhythmia >30 seconds by 1 year, and 15 (35%) patients had atrial tachyarrhythmia recurrences by 1 year. Eight of 15 patients with recurrent AF had catheter ablation resulting in elimination and/or reduction of AF episodes in 7 of 8 patients. Four of 15 patients had AF elimination or reduction with antiarrhythmic drugs alone. Three patients did not benefit from surgery and received rate control only. There were no deaths; 1 phrenic nerve injury and 2 pleural effusions were the only major complications. Conclusions—The single procedure success at 1-year follow-up for surgical pulmonary vein isolation and ganglionic plexi ablation is 65%. Atrial tachyarrhythmia recurrences after surgery are usually responsive to catheter ablation and/or antiarrhythmic drugs.

Quantification of the cryoablation zone demarcated by pre- and postprocedural electroanatomic mapping in patients with atrial fibrillation using the 28-mm second-generation cryoballoon.

BACKGROUND Since the release of the second-generation cryoballoon (CB2; Arctic Front Advance(TM), Medtronic Inc) and its design modifications with improved cooling characteristics, the technique, dosing, and complication profile is significantly different from that of the first-generation cryoballoon. A comprehensive report of CB2 procedural recommendations has not been reported. OBJECTIVE The purpose of this study was to review the current best practices from a group of experienced centers to create a users consensus guide for CB2 ablation. METHODS/RESULTS High-volume operators with a combined experience of more than 3000 CB2 cases were interviewed, and consensus for technical and procedural best practice was established. CONCLUSION Comprehensive review of the CB2 ablation best practice guide will provide a detailed technique for achieving safer and more effective outcomes for CB2 atrial fibrillation ablation.

Management of Recurrent Atrial Arrhythmias After Minimally Invasive Surgical Pulmonary Vein Isolation and Ganglionic Plexi Ablation for Atrial Fibrillation

There are limited comparative data on catheter ablation of atrial fibrillation (CAAF) using the second‐generation cryoballoon (CB‐2) versus point‐by‐point radiofrequency (RF). This study examines the acute/long‐term CAAF outcomes using these 2 strategies.

Recordings of diaphragmatic electromyograms during cryoballoon ablation for atrial fibrillation accurately predict phrenic nerve injury.

BACKGROUND There are 2 Food and Drug Administration-approved catheters (ThermoCool RF and Arctic Front Advance cryoballoon) for the treatment of drug refractory and symptomatic paroxysmal atrial fibrillation. Each tool is used to ablate the area surrounding the pulmonary veins (PVs). However, no study has described and quantified the ablated surface area after the application of cryoablation lesions with the second-generation cryoballoon. OBJECTIVE The purpose of this study was to determine the area of ablation during cryoballoon PV isolation. METHODS Preprocedural computed tomography angiography of the left atrium (LA) was conducted in 43 patients to accurately determine spatial chamber dimensions. Before and after the ablation procedure, a detailed 3-dimensional electroanatomic map of the LA was created and merged onto the computed tomography angiogram to improve the accuracy of the data recordings. RESULTS The posterior LA wall had a mean surface area of 31.1 (±1.6 SEM) cm(2). Left- and right-sided antral PV surface areas of cryoballoon ablation were not statistically different (P = .935), which were 11.4 (±0.8 SEM) and 11.3 (±0.8 SEM) cm(2), respectively. In total, 27% of the posterior LA wall remained unablated, electrically functional, and homogeneous with regard to voltage conductivity. This ablation strategy resulted in 95.3% freedom from atrial fibrillation at 6 months. CONCLUSION The area of the posterior LA wall ablation with the cryoballoon catheter is wide and antral, and the resulting posterior LA wall debulking could be a part of the cryoballoon efficacy beyond discrete PV isolation.

Trends in Hospitalization for Atrial Fibrillation: Epidemiology, Cost, and Implications for the Future

BACKGROUND Minimally invasive thoracoscopic procedures have evolved for surgical treatment of atrial fibrillation (AF). The spectrum and management of arrhythmias after minimally invasive epicardial radiofrequency ablation of the pulmonary vein (PV) antrum have not been well studied. OBJECTIVE The aim of this study was to describe the spectrum and treatment of recurrent atrial tachyarrhythmias (AT) after minimally invasive AF surgery. METHODS Fifty patients underwent bipolar radiofrequency (RF) ablation of the PV antrum, parasympathetic ganglionated plexi, and ligament of Marshall. Twenty patients (40%) had recurrent AT, and 13 underwent electrophysiology study 100 to 948 days postoperatively (mean 383 +/- 234). RESULTS Fourteen arrhythmias were identified in 13 patients 90 to 666 days (mean 214 +/- 162) after AF surgery. The most common arrhythmias were AF (N = 8) and atrial flutter (N = 3). Of 44 PVs examined, 22 (50%) had reconnected. Seven of 8 patients with recurrent AF had either 2 or 3 veins reconnected, and 6 of 8 had reconnection of the left superior PV. On average, 25.6% of each PV reconnected and showed conduction delay between the left atrium and PV. Two of 4 postoperative atrial flutters were due to isthmus-dependent re-entry. After catheter ablation, 2 patients had symptomatic recurrence of AT. CONCLUSION Recurrent AT occurs in up to 40% of patients after minimally invasive thoracoscopic AF surgery during a minimal follow-up of 12 months. PV reconnection accounts for most recurrences. Postoperative AT appears amenable to catheter ablation, often in conjunction with medical therapy, with high intermediate-term success.