Gabriele Vicedomini

Circumferential Radiofrequency Ablation of Pulmonary Vein Ostia

Background The pulmonary veins (PVs) and surrounding ostial areas frequently house focal triggers or reentrant circuits critical to the genesis of atrial fibrillation (AF). We developed an anatomic approach aimed at isolating each PV from the left atrium (LA) by circumferential radiofrequency (RF) lesions around their ostia. Methods and results We selected 26 patients with resistant AF, either paroxysmal (n=14) or permanent (n=12). A nonfluoroscopic mapping system was used to generate 3D electroanatomic LA maps and deliver RF energy. Two maps were acquired during coronary sinus and right atrial pacing to validate the lateral and septal PV lesions, respectively. Patients were followed up closely for >/=6 months. Procedures lasted 290+/-58 minutes, including 80+/-22 minutes for acquisition of all maps, and 118+/-16 RF pulses were deployed. Among 14 patients in AF at the beginning of the procedure, 64% had sinus rhythm restoration during ablation. PV isolation was demonstrated in 76% of 104 PVs treated by low peak-to-peak electrogram amplitude (0. 08+/-0.02 mV) inside the circular line and by disparity in activation times (58+/-11 ms) across the lesion. After 9+/-3 months, 22 patients (85%) were AF-free, including 62% not taking and 23% taking antiarrhythmic drugs, with no difference (P:=NS) between paroxysmal and permanent AF. No thromboembolic events or PV stenoses were observed by transesophageal echocardiography. Conclusions Radiofrequency PV isolation with electroanatomic guidance is safe and effective in either paroxysmal or permanent AF.

Pulmonary Vein Denervation Enhances Long-Term Benefit After Circumferential Ablation for Paroxysmal Atrial Fibrillation

Background—There are no data to evaluate the relationship between autonomic nerve function modification and recurrent atrial fibrillation (AF) after circumferential pulmonary vein ablation (CPVA). This study assesses the incremental benefit of vagal denervation by radiofrequency in preventing recurrent AF in a large series of patients undergoing CPVA for paroxysmal AF. Methods and Results—Data were collected on 297 patients undergoing CPVA for paroxysmal AF. Abolition of all evoked vagal reflexes around all pulmonary vein ostia was defined as complete vagal denervation (CVD) and was obtained in 34.3% of patients. Follow-up ended at 12 months. Heart rate variability attenuation, consistent with vagal withdrawal, was detectable for up to 3 months after CPVA, particularly in patients with reflexes and CVD, who were less likely to have recurrent AF than those without reflexes (P =0.0002, log-rank test). Only the percentage area of left atrial isolation and CVD were predictors of AF recurrence after CPVA (P <0.001 and P =0.025, respectively). Conclusions—This study suggests that adjunctive CVD during CPVA significantly reduces recurrence of AF at 12 months.

Atrial Electroanatomic Remodeling After Circumferential Radiofrequency Pulmonary Vein Ablation Efficacy of an Anatomic Approach in a Large Cohort of Patients With Atrial Fibrillation

Background—Circumferential radiofrequency ablation around pulmonary vein (PV) ostia has recently been described as a new anatomic approach for atrial fibrillation (AF). Methods and Results—We treated 251 consecutive patients with paroxysmal (n=179) or permanent (n=72) AF. Circular PV lesions were deployed transseptally during sinus rhythm (n=124) or AF (n=127) using 3D electroanatomic guidance. Procedures lasted 148±26 minutes. Among 980 lesions surrounding individual PVs (n=956) or 2 ipsilateral veins with close openings or common ostium (n=24), 75% were defined as complete by a bipolar electrogram amplitude <0.1 mV inside the lesion and a delay >30 ms across the line. The amount of low-voltage encircled area was 3594±449 mm2, which accounted for 23±9% of the total left atrial (LA) map surface. Major complications (cardiac tamponade) occurred in 2 patients (0.8%). No PV stenoses were detected by transesophageal echocardiography. After 10.4±4.5 months, 152 patients with paroxysmal AF (85%) and 49 with permanent AF (68%) were AF-free. Patients with and without AF recurrence did not differ in age, AF duration, prevalence of heart disease, or ejection fraction, but the LA diameter was significantly higher (P <0.001) in permanent AF patients with recurrence. The proportion of PVs with complete lesions was similar between patients with and without recurrence, but the latter had larger low-voltage encircled areas after radiofrequency (expressed as percent of LA surface area;P <0.001). Conclusions—Circumferential PV ablation is a safe and effective treatment for AF. Its success is likely due to both PV trigger isolation and electroanatomic remodeling of the area encompassing the PV ostia.

Atrio-Esophageal Fistula as a Complication of Percutaneous Transcatheter Ablation of Atrial Fibrillation

Background—Radiofrequency ablation for atrial fibrillation is becoming widely practiced. Methods and Results—Two patients undergoing circumferential pulmonary vein ablation for atrial fibrillation in different centers developed symptoms compatible with endocarditis 3 to 5 days after the procedure. Their clinical condition deteriorated rapidly, and both suffered multiple gaseous and/or septic embolic events causing cerebral and myocardial damage. One patient survived after emergency cardiac and esophageal surgery; the other died of extensive systemic embolization. An atrio-esophageal fistula was identified in both patients. Conclusions—Atrio-esophageal fistulas can occur after catheter ablation in the posterior wall of the left atrium. This diagnosis should be excluded in any patient with symptoms or signs of endocarditis after left atrial ablation, and expeditious cardiac surgery is critical if the diagnosis is confirmed. Lower power and temperature settings for applications of radiofrequency energy along the posterior left atrial wall may prevent further cases of fistula formation.

Prevention of Iatrogenic Atrial Tachycardia After Ablation of Atrial Fibrillation A Prospective Randomized Study Comparing Circumferential Pulmonary Vein Ablation With a Modified Approach

Background—Circumferential pulmonary vein ablation (CPVA) is effective in curing atrial fibrillation (AF), but new-onset left atrial tachycardia (AT) is a potential complication. We evaluated whether a modified CPVA approach including additional ablation lines on posterior wall and the mitral isthmus would reduce the incidence of AT after PV ablation. Methods and Results—A total of 560 patients (291 men, 52%; age, 56.5±7.3 years) entered the study; 280 were randomized to CPVA alone (group 1) and 280 to modified CPVA (group 2). The primary end point was freedom from AT after the procedure. In group 1, 28 patients (10%) experienced new-onset AT, and 41 (14.3%) experienced recurrent AF. In group 2, 11 patients (3.9%) experienced AT, and 36 (12.9%) had recurrent AF. Group 1 was more likely to experience AT than group 2 (P=0.005). Freedom from AF after ablation was similar in both groups (P=0.57). Among those in group 1, gap-related macroreentrant AT was documented in 23 of the 28 patients (82%), and focal AT was found in 5 (18%). In group 2, gap-related macroreentrant AT was found in 8 of the 11 patients (73%), and focal AT was seen in 3 (27%). Two patients in group 1 and 1 patient in group 2 had both AT and AF. The strongest predictor of AT was the presence of gaps (P<0.001). Conclusions—Modified CPVA is as effective as CPVA in preventing AF but is associated with a lower risk of developing incessant AT.

Catheter Ablation of Paroxysmal Atrial Fibrillation Using a 3D Mapping System

BACKGROUND We treated paroxysmal recurrent atrial fibrillation (AF) with radiofrequency (RF) catheter ablation by creating long linear lesions in the atria. To achieve line continuity, a 3D electroanatomic nonfluoroscopic mapping system was used. METHODS AND RESULTS In 27 patients with recurrent AF, a catheter incorporating a passive magnetic field sensor was navigated in both atria to construct a 3D activation map. RF energy was delivered to create continuous linear lesions: 3 lines (intercaval, isthmic, and anteroseptal) in the right atrium and a long line encircling the pulmonary veins in the left atrium. After RF application, the atria were remapped to validate completeness of the block lines, demonstrated by late activation of the areas circumscribed by the lines. The mean procedure duration was 312+/-103 minutes (range, 187 to 495), with mean fluoroscopy time of 107+/-44 minutes (range, 32 to 185 minutes). No acute complications occurred, but 1 patient experienced early prolonged sinus pauses and received a pacemaker. During the first day, 17 patients (63%) had AF episodes, but at discharge, 25 patients were in sinus rhythm. After a follow-up of 6. 0 to 15.3 months (average, 10.5+/-3.0 months), 16 patients are asymptomatic, 3 have an almost complete disappearance of symptoms, 1 patient is improved, and 7 patients have their AF attacks unchanged. CONCLUSIONS Paroxysmal recurrent drug-refractory AF can be treated by RF catheter ablation. Creation of long continuous linear lesions necessary to compartmentalize the atria is facilitated by a nonfluoroscopic electroanatomic mapping system.

Usefulness of Invasive Electrophysiologic Testing to Stratify the Risk of Arrhythmic Events in Asymptomatic Patients With Wolff-Parkinson-White Pattern Results From a Large Prospective Long-Term Follow-Up Study

OBJECTIVES The aim of this study was to assess in a large cohort of asymptomatic subjects with Wolff-Parkinson-White (WPW) pattern the usefulness of invasive electrophysiologic testing (EPT) in predicting the occurrence of arrhythmic events over a five-year follow-up. BACKGROUND Sudden death may be the first clinical manifestation of the WPW syndrome in previously asymptomatic patients. Serial EPTs have been proposed to identify patients at risk. METHODS A total of 212 consecutive asymptomatic WPW patients were enrolled after a baseline EPT; patients were followed for five years, and 162 patients (115 noninducible and 47 inducible) patients underwent a second EPT. RESULTS After a mean follow-up of 37.7 months, 33 patients became symptomatic. Of the 115 noninducible patients, 18.2% lost anterograde accessory pathway (AP) conduction, 30% retrograde AP conduction, and only 4 (3.4%) developed symptomatic supraventricular tachycardia (SVT). Of the 47 inducible patients, 25 with sustained atrioventricular reciprocating tachycardia (AVRT) and atrial fibrillation (AF), and 4 with nonsustained AVRT and AF became symptomatic for SVT (n = 21) and AF (n = 8). They were younger, had shorter AP anterograde refractory periods, and multiple APs compared to patients who remained asymptomatic (for all comparisons, p < 0.0001). Of the eight patients with symptomatic episodes of AF and inducible sustained AF, two had a resuscitated cardiac arrest and one died suddenly; all three patients were inducible for AVRT and AF and had multiple APs. CONCLUSIONS In asymptomatic WPW subjects, EPT may be a valuable tool to stratify the risk of symptomatic and fatal arrhythmic events.

The Natural History of Asymptomatic Ventricular Pre-Excitation A Long-Term Prospective Follow-Up Study of 184 Asymptomatic Children

OBJECTIVES The aim of this study was to describe the natural history of asymptomatic ventricular pre-excitation in children and to determine predictors of potentially life-threatening arrhythmic events. BACKGROUND Sudden death can be the first clinical manifestation in asymptomatic children with ventricular pre-excitation, but reduction of its incidence by prophylactic ablation requires the identification of subjects at high risk. METHODS Between 1995 and 2005 we prospectively collected clinical and electrophysiologic data from 184 children (66% male; median age 10 years; range 8 to 12 years) with asymptomatic ventricular pre-excitation on the electrocardiogram. After electrophysiologic testing, subjects were followed as outpatients taking no medications. The primary end point of the study was the occurrence of arrhythmic events. Predictors of potentially life-threatening arrhythmias were analyzed. RESULTS Over a median follow-up of 57 months (min/max 32/90 months) after electrophysiologic testing, 133 children (mean age 10 years; range 8 to 12 years) did not experience arrhythmic events, remaining totally asymptomatic, while 51 children had within 20 months (min/max 8/60 months) a first arrhythmic event, which was potentially life-threatening in 19 of them (mean age 10 years; range 10 to 14 years). Life-threatening tachyarrhythmias resulted in cardiac arrest (3 patients), syncope (3 patients), atypical symptoms (8 patients), or minimal symptoms (5 patients). Univariate analysis identified tachyarrhythmia inducibility (p < 0.001), anterograde refractory period of accessory pathways (APERP) </=240 ms (p < 0.001), and multiple accessory pathways (p < 0.001) as risk factors for potentially life-threatening arrhythmic events. Independent predictors by multivariate analysis were APERP (p = 0.001) and multiple accessory pathway (p = 0.001). CONCLUSIONS These findings are potentially relevant in terms of early identification of high-risk asymptomatic children with ventricular pre-excitation. Subjects with short APERPs and multiple pathways are at higher risk of developing life-threatening arrhythmic events and are the best candidates for prophylactic ablation.

Morbidity, mortality, and quality of life after circumferential pulmonary vein ablation for atrial fibrillation ☆

Objectives This study was designed to investigate the potential of circumferential pulmonary vein (PV) ablation for atrial fibrillation (AF) to maintain sinus rhythm (SR) over time, thus reducing mortality and morbidity while enhancing quality of life (QoL). Background Circumferential PV ablation is safe and effective, but the long-term outcomes and its impact on QoL have not been assessed or compared with those for medical therapy. Methods We examined the clinical course of 1,171 consecutive patients with symptomatic AF who were referred to us between January 1998 and March 2001. The 589 ablated patients were compared with the 582 who received antiarrhythmic medications for SR control. The QoL of 109 ablated and 102 medically treated patients was measured with the SF-36 survey. Results Median follow-up was 900 days (range 161 to 1,508 days). Kaplan-Meier analysis showed observed survival for ablated patients was longer than among patients treated medically (p < 0.001), and not different from that expected for healthy persons of the same gender and calendar year of birth (p = 0.55). Cox proportional-hazards model revealed in the ablation group hazard ratios of 0.46 (95% confidence interval [CI], 0.31 to 0.68; p < 0.001) for all-cause mortality, of 0.45 (95% CI, 0.31 to 0.64; p < 0.001) for morbidities mainly due to heart failure and ischemic cerebrovascular events, and of 0.30 (95% CI, 0.24 to 0.37; p < 0.001) for AF recurrence. Ablated patients’ QoL, different from patients treated medically, reached normative levels at six months and remained unchanged at one year. Conclusions Pulmonary vein ablation improves mortality, morbidity, and QoL as compared with medical therapy. Our findings pave the way for randomized trials to prospect a wider application of ablation therapy for AF.

Atrial fibrillation progression and management: A 5-year prospective follow-up study

BACKGROUND Few data on atrial fibrillation (AF) progression from the first paroxysmal episode are available. OBJECTIVE The purpose of this study was to assess the progression of AF not due to potentially reversible causes in patients treated according to current guidelines recommendations that also include catheter ablation. METHODS Among 402 screened patients with first AF, 106 patients (mean age 57.5 years) were selected and followed for 5 years. Of these patients, 54 had lone AF and 52 had comorbidities. RESULTS Fifty patients (61.1% with lone AF) had no further recurrence after 5 years. The remaining 56 patients within 19 months after the first episode developed recurrent paroxysmal AF requiring long-term antiarrhythmic drug therapy, which was continued in 45 patients and was stopped because of intolerance/failure in 11 patients who underwent catheter ablation. AF became persistent in 24 of the 45 patients on antiarrhythmic drug therapy and then permanent in 16, of whom 6 had refused catheter ablation at the time of persistence. No AF recurrences or AF progression occurred after ablation. Kaplan-Meier curves demonstrated that patients with comorbidities were more likely to progress than were those with lone AF (P <.001) and that patients who underwent catheter ablation were at lower risk for progression to permanent AF than were those on antiarrhythmic drug therapy (P = .029). Age, diabetes, and heart failure (P <.001) predict final progression to permanent AF. CONCLUSION Patients with first AF and comorbidities are at higher risk for rapid progression to permanent AF, and age, diabetes, and heart failure are independent predictors. Catheter ablation rather than antiarrhythmic drug therapy is beneficial in eliminating recurrences delaying arrhythmia progression.