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Background: The implantable cardioverter-defibrillator (ICD) is the standard therapy to prevent sudden cardiac death in patients with coronary artery disease and unstable ventricular tachyarrhythmias. The prospective multinational SMS (Substrate Modification Study) was designed to assess whether prophylactic ablation of the arrhythmogenic substrate reduces or prevents the recurrence of ventricular tachycardia/ventricular fibrillation in such patients.Methods and Results: Of 111 patients included in an intention-to-treat analysis, 54 were randomly assigned catheter ablation plus ICD implantation (ablation group: 68±8 years; 47 men), whereas 57 were assigned ICD implantation without catheter ablation (ICD-only group: 66±8 years; 46 men). Primary study end point was the time to first recurrence of ventricular tachycardia/ventricular fibrillation. ICD episodes were assessed and verified by an independent board. Patients were followed up for 2.3±1.1 years. The primary end point was reached by 25 ablation patients and 26 ICD-only patients. Two-year event-free survival was estimated at 49.0% (95% confidence interval, 33.3%-62.9%) in the former and 52.4% (36.7%-65.9%) in the latter groups. Comparison of episode incidence revealed no significant difference in the primary end point (P=0.84). In an Andersen-Gill regression model with multiple end point recurrences, the difference between the study arms significantly favored catheter ablation for both the primary end point and all but one of the predefined subgroups of detected arrhythmia events.Conclusions: SMS failed to meet the primary end point of time to first ventricular tachycardia/ventricular fibrillation recurrence. However, catheter ablation did reduce the total number of ICD interventions during the duration of follow-up.Clinical Trial Registration: https://clinicaltrials.gov. Unique identifier: NCT00170287. [ABSTRACT FROM AUTHOR]

Background: Early recurrences (ERs) of atrial tachyarrhythmia are common after catheter ablation of atrial fibrillation. A 3-month blanking period is recommended by current guidelines. This study sought to investigate the significance of ER during the first 3 months post ablation in predicting late recurrences and determine whether it varies according to timing.Methods and Results: A total of 401 patients with paroxysmal atrial fibrillation undergoing pulmonary vein isolation were followed for 12 months with transtelephonic monitoring in the ADVICE (Adenosine Following Pulmonary Vein Isolation to Target Dormant Conduction Elimination) trial. Patients with atrial tachyarrhythmia ≥30 s within the 3-month blanking period were stratified according to the timing of ER. A total of 179 patients (44.6%) experienced their last episode of ER during the first (n=53), second (n=44), or third (n=82) month of the 3-month blanking period. One-year freedom from symptomatic atrial tachyarrhythmia was 77.2% in patients without ER compared with 62.6%, 36.4%, and 7.8% in patients with ER 1, 2, and 3 months post ablation, respectively (P<0.0001). Receiver operating curve analyses revealed a strong correlation between the timing of ER and late recurrence (area under the curve 0.82, P<0.0001). Corresponding hazard ratios for ER during the first, second, and third months were 1.84, 4.45, and 9.64, respectively.Conclusions: This study validates the use of a blanking period after catheter ablation for paroxysmal atrial fibrillation but calls into question the 90-day cut-off value. In particular, >90% of patients with ER during the third month post ablation experience late recurrence by 1 year. However, pending further study, repeat ablation before 90 days cannot be routinely advocated.Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01058980. [ABSTRACT FROM AUTHOR]

Background: The success rate of catheter ablation for persistent atrial fibrillation (AF) is still far from satisfactory. Identification of patients who will benefit from ablation is highly desirable. We investigated the predictive value of noninvasive AF complexity parameters derived from standard 12-lead ECGs for AF termination and long-term success of catheter ablation and compared them with clinical predictors.Methods and Results: The study included a training (93 patients) and a validation set (81 patients) of patients with persistent AF undergoing stepwise radiofrequency ablation. In the training set AF terminated in 81% during catheter ablation, 77% were in sinus rhythm after 6 years and multiple ablations. ECG-derived complexity parameters were determined from a baseline 10-s 12-lead ECG. Prediction of AF termination was similar using only ECG (cross-validated mean area under the curve [AUC], 0.76±0.15) or only clinical parameters (mean AUC, 0.75±0.16). The combination improved prediction to a mean AUC of 0.79±0.13. Using a combined model of ECG and clinical parameters, sinus rhythm at long-term follow-up could be predicted with a mean AUC of 0.71±0.12. In the validation set AF terminated in 57%, 61% were in sinus rhythm after 4.6 years. The combined models predicted termination with an AUC of 0.70 and sinus rhythm at long-term follow-up with an AUC of 0.61. Overall, fibrillation-wave amplitude provided the best rhythm prediction.Conclusions: The predictive performance of ECG-derived AF complexity parameters for AF termination and long-term success of catheter ablation in patients with persistent AF is at least as good as known clinical predictive parameters, with fibrillation-wave amplitude as the best predictor. [ABSTRACT FROM AUTHOR]

Background: Ablation of atrial fibrillation (AF) is an established treatment option for symptomatic patients. It is not known whether complete pulmonary vein isolation (PVI) is superior to incomplete PVI with regard to the patients' clinical outcome.Methods and Results: Patients with drug-refractory, symptomatic paroxysmal AF were randomly assigned to either incomplete (group A) or complete PVI (group B). In group A, a persistent gap was intentionally left within the circumferential ablation line, whereas in group B, complete PVI without any gaps was intended. At 3 months, all patients underwent invasive reevaluation to assess the rate of persistent PVI. Clinical follow-up was based on daily 30-s transtelephonic ECG transmissions. Primary study end point was the time to first recurrence of (symptomatic or asymptomatic) AF. A total of 233 patients were enrolled (116 in group A and 117 in group B). AF recurrence within 3 months was observed in a total of 161 patients (136 [84.5%] with symptomatic and 25 [15.5%] with asymptomatic AF); AF recurred in 62.2% of group B patients and 79.2% of group A patients (P<0.001), for a difference in favor of complete PVI of 17.1% (95% confidence interval, 5.3%-28.9%). Invasive restudy in 103 group A patients and 93 group B patients revealed conduction gaps in 92 (89.3%) and 65 (69.9%) patients, respectively.Conclusions: This study proves the superiority of complete PVI over incomplete PVI with respect to AF recurrence within 3 months. However, the rate of electric reconduction 3 months after PVI is high in patients with initially isolated PVs.Clinical Trial Registration: URL: http://clinicaltrials.gov; Unique identifier: NCT00293943. [ABSTRACT FROM AUTHOR]

The article assesses the efficacy of subcutaneous implantable cardioverter-defibrillator (S-ICD) in a clinical setting. It informs that ICD therapy is established as the best option to prevent sudden cardiac death due to ventricular tachyarrythmia. It concludes that ineffective shock delivery may occur in patients with S-ICD even after successful intraoperative testing. The article also suggests that multicenter trials are required with close monitoring of safety and efficacy end points.

The article discusses a study which examined the mechanisms and success rates of conventional mapping and catheter ablation of recurrent atrial tachycardias (AT) after stepwise ablation of long-lasting persistent atrial fibrillation (CAF). The study included 320 patients who underwent de novo ablation of CAF using a stepwise ablation in 2006 and 2007. Study authors concluded that catheter ablation guided by conventional techniques is an effective treatment approach to late recurrent AT.

The article presents a study on the acute success rates of termination of chronic atrial fibrillation (CAF) using a sequential ablation approach and on the contribution of the right atrium to the CAF process. The results of the study showed that atrial fibrillation termination is a prognostic crucial end point of catheter ablation for CAF. It also mentions that subsequent arrythmias requently recur during follow-up, thus, should be targeted for ablation.

Background: Termination of persistent atrial fibrillation (AF) can be achieved through ablation, with the majority of patients terminating to an atrial tachycardia (AT) and fewer directly to sinus rhythm (SR). We aimed to identify potential predictors for the existence of a substrate for AT on termination to SR., Methods and Results: We assessed 95 persistent AF patients (age, 60+/-10 years) who underwent catheter ablation to the end point of AF termination. Forty patients terminated directly to SR (SRterm) and 55 to ATs (ATterm). Compared with the ATterm group, the SRterm group were younger (56+/-10 versus 63+/-9 years, P=0.001), had shorter durations of AF before ablation (9+/-26 versus 14+/-20 months, P<0.001), smaller left atrial diameters (41+/-5 versus 45+/-5 mm, P=0.015), and longer baseline AF cycle lengths (178+/-23 versus 159+/-31 ms, P=0.005). However, AF cycle length was the sole independent predictor of direct termination to SR. The most frequent AF termination site in SRterm patients was the pulmonary veins (53%), whereas in ATterm patients this was within the left atrium (58%). After follow-up of 12+/-6 months, there was a trend toward a greater proportion of patients in SR among those who terminated directly to SR after a single procedure. The most frequent type of recurrence was paroxysmal AF in SRterm patients and AT in ATterm patients., Conclusions: Patients who terminate to SR through ablation without an intermediate AT are characterized by a less altered arrhythmogenic substrate. Baseline AF cycle lengths emerged as a sole independent predictor of a substrate for consecutive arrhythmias.