Thomas Rostock

Sudden Cardiac Arrest Associated with Early Repolarization

BACKGROUND Early repolarization is a common electrocardiographic finding that is generally considered to be benign. Its potential to cause cardiac arrhythmias has been hypothesized from experimental studies, but it is not known whether there is a clinical association with sudden cardiac arrest. METHODS We reviewed data from 206 case subjects at 22 centers who were resuscitated after cardiac arrest due to idiopathic ventricular fibrillation and assessed the prevalence of electrocardiographic early repolarization. The latter was defined as an elevation of the QRS-ST junction of at least 0.1 mV from baseline in the inferior or lateral lead, manifested as QRS slurring or notching. The control group comprised 412 subjects without heart disease who were matched for age, sex, race, and level of physical activity. Follow-up data that included the results of monitoring with an implantable defibrillator were obtained for all case subjects. RESULTS Early repolarization was more frequent in case subjects with idiopathic ventricular fibrillation than in control subjects (31% vs. 5%, P<0.001). Among case subjects, those with early repolarization were more likely to be male and to have a history of syncope or sudden cardiac arrest during sleep than those without early repolarization. In eight subjects, the origin of ectopy that initiated ventricular arrhythmias was mapped to sites concordant with the localization of repolarization abnormalities. During a mean (+/-SD) follow-up of 61+/-50 months, defibrillator monitoring showed a higher incidence of recurrent ventricular fibrillation in case subjects with a repolarization abnormality than in those without such an abnormality (hazard ratio, 2.1; 95% confidence interval, 1.2 to 3.5; P=0.008). CONCLUSIONS Among patients with a history of idiopathic ventricular fibrillation, there is an increased prevalence of early repolarization.

Catheter Ablation of Long-Lasting Persistent Atrial Fibrillation: Clinical Outcome and Mechanisms of Subsequent Arrhythmias

Background: Catheter ablation of atrial fibrillation (AF) is challenging in patients with long‐standing persistent AF. The clinical outcome and subsequent arrhythmia recurrence after using an ablation method targeting multiple left atrial sites with the aim of achieving acute AF termination has not been characterized.

Catheter Ablation of Long-Lasting Persistent Atrial Fibrillation: Critical Structures for Termination

Background: The relative contributions of different atrial regions to the maintenance of persistent atrial fibrillation (AF) are not known.

Techniques, Evaluation, and Consequences of Linear Block at the Left Atrial Roof in Paroxysmal Atrial Fibrillation A Prospective Randomized Study

BACKGROUND There are no reports describing the technique, electrophysiological evaluation, and clinical consequences of complete linear block at roofline joining the superior pulmonary veins (PVs) in patients with paroxysmal atrial fibrillation (AF). METHODS AND RESULTS Ninety patients with drug-refractory paroxysmal AF undergoing radiofrequency ablation were prospectively randomized into 2 ablation strategies: (1) PV isolation (n=45) or (2) PV isolation in combination with linear ablation joining the 2 superior PVs (roofline; n=45). In both groups, the cavotricuspid isthmus, fragmented peri-PV-ostial electrograms, and spontaneous non-PV foci were ablated. Roofline ablation was performed at the most cranial part of the left atrium (LA) with complete conduction block demonstrated during LA appendage pacing by the online mapping of continuous double potential and an activation detour propagating around the PVs to activate caudocranially the posterior wall of the LA. The effect of ablation at the LA roof was evaluated by the change in fibrillatory cycle length, termination and noninducibility of AF, and clinical outcome. PV isolation was achieved in all patients with no significant differences in the radiofrequency duration, fluoroscopy, or procedural time between the groups. Roofline ablation required 12+/-6 (median 11, range 3 to 25) minutes of radiofrequency energy delivery with a fluoroscopic duration of 7+/-2 minutes and was performed in 19+/-7 minutes. Complete block was confirmed in 43 patients (96%) and resulted in an activation delay that was shorter circumventing the left than the right PVs during LA appendage pacing (138+/-15 versus 146+/-25 ms, respectively; P=0.01). Roofline ablation resulted in a significant increase in the fibrillatory cycle length (198+/-38 to 217+/-44 ms; P=0.0005), termination of arrhythmia in 47% (8/17), and subsequent noninducibility of AF in 59% (10/17) of the patients inducible after PV isolation. However, LA flutter, predominantly perimitral, could be induced in 10 patients (22%) after roofline ablation. At 15+/-4 months, 87% of the roofline group and 69% with PV isolation alone are arrhythmia free without antiarrhythmics (P=0.04). CONCLUSIONS This prospective randomized study demonstrates the feasibility of achieving complete linear block at the LA roof. Such ablation resulted in the prolongation of the fibrillatory cycle, termination of AF, and subsequent noninducibility and is associated with an improved clinical outcome compared with PV isolation alone.

Characterization of electrograms associated with termination of chronic atrial fibrillation by catheter ablation.

OBJECTIVES This study sought to determine the characteristics of atrial electrograms predictive of slowing or termination of atrial fibrillation (AF) during ablation of chronic AF. BACKGROUND There is growing recognition of a role for electrogram-based ablation. METHODS Forty consecutive patients (34 male, 59 +/- 10 years) undergoing ablation for chronic AF persisting for a median of 12 months (range 1 to 84 months) were included. After pulmonary vein isolation and roof line ablation, electrogram-based ablation was performed in the left atrium and coronary sinus. Targeted electrograms were acquired in a 4-s window and characterized by: 1) percentage of continuous electrical activity; 2) bipolar voltage; 3) dominant frequency; 4) fractionation index; 5) mean absolute value of derivatives of electrograms; 6) local cycle length; and 7) presence of a temporal gradient of activation. Electrogram characteristics at favorable ablation regions, defined as those associated with slowing (a >or=6-ms increase in AF cycle length) or termination of AF were compared with those at unfavorable regions. RESULTS The AF was terminated by electrogram-based ablation in 29 patients (73%) after targeting a total of 171 regions. Ablation at 37 (22%) of these regions was followed by AF slowing, and at 29 (17%) by AF termination. The percentage of continuous electrical activity and the presence of a temporal gradient of activation were independent predictors of favorable ablation regions (p = 0.016 and p = 0.038, respectively). Other electrogram characteristics at favorable ablation regions were not significantly different from those at unfavorable ablation regions. CONCLUSIONS Catheter ablation at sites displaying a greater percentage of continuous activity or a temporal activation gradient is associated with slowing or termination of chronic AF.

Localized Sources Maintaining Atrial Fibrillation Organized by Prior Ablation

Background— Endocardial mapping of localized sources driving atrial fibrillation (AF) in humans has not been reported. Methods and Results— Fifty patients with AF organized by prior pulmonary vein and linear ablation were studied. AF was considered organized if mapping during AF showed irregular but discrete atrial complexes exhibiting consistent activation sequences for >75% of the time using a 20-pole catheter with 5 radiating spines covering 3.5-cm diameter or sequential conventional mapping. A site or region centrifugally activating the remaining atrial tissue defined a source. During AF with a cycle length of 211±32 ms, activation mapping identified 1 to 3 sources at the origin of atrial wavefronts in 38 patients (76%) predominantly in the left atrium, including the coronary sinus region. Electrograms at the earliest area varied from discrete centrifugal activation to an activity spanning 75% to 100% of the cycle length in 42% of cases, the latter indicating complex local conduction or a reentrant circuit. A gradient of cycle length (>20 ms) to the surrounding atrium was observed in 28%. Local radiofrequency ablation prolonged AF cycle length by 28±22 ms and either terminated AF or changed activation sequence to another organized rhythm. In 4 patients, the driving source was isolated, surrounded by the atrium in sinus rhythm, and still firing at high frequency (228±31 ms) either permanently or in bursts. Conclusions— AF associated with consistent atrial activation sequences after prior ablation emanates mostly from localized sources that can be mapped and ablated. Some sources harbor electrograms suggesting the presence of localized reentry.

The stepwise ablation approach for chronic atrial fibrillation—Evidence for a cumulative effect

Treatment options for atrial fibrillation (AF) have evolved from simple, fluoroscopy-guided pulmonary vein isolation for those patients with paroxysmal AF to complex, multi-modality procedures targeting not only anatomic structures but also electrophysiologic phenomena including complex fractionated electrograms, sites of dominant frequency and local non-venous drivers in patients with persistent and permanent AF. The stepwise ablation approach is a novel technique whereby structures contributing to initiation and maintenance of AF are sequentially targeted by radiofrequency ablation. Broadly divided into pulmonary veins, left atrial (LA) roof, left atrium (incorporating all anatomic regions of the chamber), mitral isthmus and non-LA structures, each region is targeted in sequence and the impact of ablation upon the global fibrillatory process assessed by measurement of AF cycle length (AFCL) at a site remote from the ablation target. In addition to pulmonary vein electrical disconnection and demonstrable complete conduction block across the roof and mitral isthmus lines (when performed), ablation is performed at those sites displaying continuous electrical and complex fractionated activity, with the endpoint of local organization, as well as at sites displaying electrograms consistent with focal sources driving AF. Ablation is accompanied by a cumulative increase in the AFCL prior to termination of AF by conversion either directly to sinus rhythm or to an atrial tachycardia which is then mapped conventionally and ablated. There is a ceiling of ablation within the LA beyond which further ablation is unlikely to result in a clinical benefit and should prompt evaluation of the contribution of the right atrium to maintenance of AF. The stepwise approach benefits from the integration of anatomic and electrophysiologic information to achieve a high level of success in termination of chronic AF by catheter ablation.

Long-term single- and multiple-procedure outcome and predictors of success after catheter ablation for persistent atrial fibrillation

BACKGROUND Stepwise ablation is an effective treatment for persistent atrial fibrillation (AF), although it often requires multiple procedures to eliminate recurrent arrhythmias. OBJECTIVE This study evaluated single- and multiple-procedure long-term success rates and potential predictors of a favorable single-procedure outcome of stepwise ablation for persistent AF. METHODS This study comprised 395 patients with persistent AF (duration 16 months) undergoing de novo catheter ablation using the stepwise approach. Procedural success was defined as the absence of any arrhythmia recurrence. Patient characteristics and electrophysiological parameters were analyzed with respect to single- and multiple-procedure outcomes. RESULTS After a follow-up of 27 ± 7 months, 108 (27%) patients were free of arrhythmia recurrences with a single procedure. After 2.3 ± 0.6 procedures, 312 (79%) patients were free of arrhythmia with concomitant antiarrhythmic treatment in 38% (23% on β-blocker). Female gender, duration of persistent AF, and congestive heart failure were predictive for the outcome after first ablation. However, the strongest predictors for single-procedure success were longer baseline AF cycle length (CL) and procedural AF termination. Moreover, procedural AF termination during the index procedure also predicted a favorable outcome after the last procedure, while the existence of congestive heart failure was associated with an increased risk for eventual arrhythmia recurrences. CONCLUSIONS Single-procedure long-term success is anticipated in approximately a quarter of patients undergoing de novo ablation of persistent AF. Baseline AFCL emerged as the strongest predictor of single-procedure success, while AF termination during index ablation predicts the overall outcome. However, an overall success rate of 79% is achievable with multiple procedures.

Chronic atrial fibrillation is a biatrial arrhythmia: data from catheter ablation of chronic atrial fibrillation aiming arrhythmia termination using a sequential ablation approach.

Background— Termination of chronic atrial fibrillation (CAF) can be achieved by catheter ablation using a stepwise approach. However, there are limited data on the contribution of the right atrium to the CAF process. Furthermore, the prognostic value of CAF termination remains unclear. Methods and Results— Eighty-eight patients (61±10 years of age) underwent de novo ablation of CAF in 2006 at our institution. The ablation procedure was performed sequentially in the following order: pulmonary vein isolation, defragmentation of the left atrium, coronary sinus, and right atrium. Attempted procedural end point was termination of CAF. Consecutive arrhythmias occurring after AF termination were mapped, and ablation was attempted. AF termination was achieved in 68 (77%) patients: in 37 (55%) patients it occurred in the left atrium, in 18 (26%) patients in the right atrium, and in 13 (19%) patients in the coronary sinus. In 54 patients, at least one redo was performed (total number of procedures: 154). After the first redo, another 30 patients were in sinus rhythm (total 63), 8 patients were in atrial tachycardia (AT), and 17 patients were in AF. Another 11 patients underwent a second redo. After a mean follow-up of 20±4 months, 71 (81%) patients were in sinus rhythm, 1 (1%) patient was in AT, and 16 (18%) patients were in AF. Patients with CAF termination had predominantly ATs as recurrent arrhythmias (83%), whereas those without mainly presented with recurrent CAF (85%). The overall success rate in patients with CAF termination was 95% compared with 5% of patients without CAF termination in 2 procedures (n=12). In almost all redo procedures attributable to AT, at least 1 AT during redo was documented previously. Conclusions— AF termination is a prognostic important end point of catheter ablation for CAF. Termination of AF was achieved in both atria and the coronary sinus, suggesting a biatrial substrate of CAF. Subsequent arrhythmias often recur during follow-up and, therefore, should be targeted for ablation. Received February 11, 2008; accepted September 15, 2008. # CLINICAL PERSPECTIVE {#article-title-2}Background—Termination of chronic atrial fibrillation (CAF) can be achieved by catheter ablation using a stepwise approach. However, there are limited data on the contribution of the right atrium to the CAF process. Furthermore, the prognostic value of CAF termination remains unclear. Methods and Results—Eighty-eight patients (61±10 years of age) underwent de novo ablation of CAF in 2006 at our institution. The ablation procedure was performed sequentially in the following order: pulmonary vein isolation, defragmentation of the left atrium, coronary sinus, and right atrium. Attempted procedural end point was termination of CAF. Consecutive arrhythmias occurring after AF termination were mapped, and ablation was attempted. AF termination was achieved in 68 (77%) patients: in 37 (55%) patients it occurred in the left atrium, in 18 (26%) patients in the right atrium, and in 13 (19%) patients in the coronary sinus. In 54 patients, at least one redo was performed (total number of procedures: 154). After the first redo, another 30 patients were in sinus rhythm (total 63), 8 patients were in atrial tachycardia (AT), and 17 patients were in AF. Another 11 patients underwent a second redo. After a mean follow-up of 20±4 months, 71 (81%) patients were in sinus rhythm, 1 (1%) patient was in AT, and 16 (18%) patients were in AF. Patients with CAF termination had predominantly ATs as recurrent arrhythmias (83%), whereas those without mainly presented with recurrent CAF (85%). The overall success rate in patients with CAF termination was 95% compared with 5% of patients without CAF termination in 2 procedures (n=12). In almost all redo procedures attributable to AT, at least 1 AT during redo was documented previously. Conclusions—AF termination is a prognostic important end point of catheter ablation for CAF. Termination of AF was achieved in both atria and the coronary sinus, suggesting a biatrial substrate of CAF. Subsequent arrhythmias often recur during follow-up and, therefore, should be targeted for ablation.

Acute occlusion of the left circumflex coronary artery during mitral isthmus linear ablation.

We report a case of acute occlusion of the left circumflex coronary artery during catheter ablation in the coronary sinus to complete the linear lesion between the postero‐lateral mitral annulus and the left inferior pulmonary vein for the treatment of atrial fibrillation.