Incidence of left atrial appendage thrombus on pre-procedural TOE before catheter ablation of atrial tachyarrhythmias

Introduction Transoesophageal echocardiography (TOE) is routinely performed before catheter ablation of atrial tachyarrhythmias to rule out the presence of possible left atrial thrombi. However, data to support this practice are scarce. Methods We analysed consecutive pre-procedural TOE in a high-volume electrophysiology centre for the presence of left atrial thrombi and a relevant flow reduction in the left atrial appendage (LAA) defined as LAA sludge or pronounced spontaneous echo contrast. Possible predictors of reduced flow were recorded and compared in a multivariate logistic regression analysis. Results 1676 consecutive TOE were included (1122 before pulmonary vein isolation (PVI), 436 before atrial flutter ablation, 166 before other EP studies in patients with a history of atrial tachyarrhythmias). 543 patients (32%) were female, mean age was 63±12 years and BMI was 27±5 kg/m2. Nine patients (0.5%) had an LAA thrombus on pre-procedural TOE. Ninety-five further patients (5.7%) had a relevant reduction in LAA flow as characterized by LAA sludge or spontaneous echo contrast. Further patient characteristics by LAA flow state are shown in the table. While a higher CHA2DS2-VaSc-Score was associated with the presence of LAA sludge and LAA thrombus (p=0.01), no further clinical parameters such as choice of oral anticoagulation agent were independently predictive of reduced flow velocities or thrombus in a logistic regression model (see table). Importantly, LAA thrombi also occurred in patients with a CHA2DS2-VaSc-Score ≤1 (n=1) or in sinus rhythm (n=2). Of note, 6 out of 9 patients with a LAA thrombus were anticoagulated with phenprocoumon. Conclusion LAA thrombus is a rare occurrence before an elective catheter ablation. In patients with CHA2DS2-VaSc-Score ≤1 the likelihood of LAA thrombus is so low (0.2%) that it may be considered to give up routine TOE before an EP study/ablation. FUNDunding Acknowledgement Type of funding sources: None.

Enhanced detection of atrial tachyarrhythmias with pacing devices by using more accurate atrial sensing

Purpose Cardiac pacing devices can detect and monitor atrial tachyarrhythmias (ATA) which increase the risk of thromboembolic complications. The aim of this study was to compare (1) two different atrial leads and (2) standard and optimized settings to detect ATA and reject far-field R-wave signal (FFRW). Methods This was a prospective, randomized multi-center trial comparing St. Jude Medical OptiSense lead (tip-to-ring spacing 1.1 mm) and Tendril lead (tip-to-ring spacing 10.0 mm), having programmed atrial sensitivity at 0.2 mV and post-ventricular atrial blanking at 60 ms. We measured intra-atrial amplitudes of FFRW, intrinsic atrial signals, the amount of FFRW oversensing, and other inappropriate mode switching. Results One hundred and ten patients were enrolled. The mean amplitude of sensed and paced FFRW bipolar signal was 0.13 mV vs. 0.21 mV (p < 0.001) and 0.13 mV vs. 0.26 mV (p < 0.001) with OptiSense and Tendril lead, respectively. The mean amplitude of the atrial bipolar signal was 2.84 mV with OptiSense and 3.48 mV with Tendril lead, p = 0.014. With the optimized settings with OptiSense lead, one patient out of 20 (5%) had FFRW oversensing, none had undersensing of ATAs due to 2:1-blanking of atrial depolarizations, and the concordance of the ATAs by Holter and pacemaker memory was high (Spearman’s rank correlation coefficient = 0.90). In the Tendril group, 12 out of 25 patients (48%) had oversensing and 4 had atrial undersensing (p < 0.001). Conclusions The technique with an atrial lead with short tip-to-ring spacing combined with optimized pacemaker programming resulted in reliable and accurate atrial arrhythmia detection. Trial registration ClinicalTrials.gov number NCT01074749.

Cryoablation versus anti-arrhythmic therapy for initial treatment of atrial fibrillation: a systematic review and meta-analysis

Introduction Atrial fibrillation is a common cardiac arrhythmia that affects approximately 2% of the overall population. Guidelines suggest the use of anti-arrhythmic agents as initial therapy in patients with symptomatic atrial fibrillation, however using cryoablation as a first line therapy might have increased efficacy. The safety and efficacy of cryoablation as initial therapy has not yet been established. Purpose We performed a systematic review and meta-analysis of randomized controlled trials to investigate the use of cryoballoon catheter ablation compared to anti-arrhythmic therapy as an initial intervention to prevent recurrence of atrial tachyarrhythmias in patients with atrial fibrillation. We also wanted to determine if using this initial ablative approach did not present increased adverse events. Methods A comprehensive search of multiple databases was performed to find randomized control trials that directly compared cryoablation therapy versus anti-arrhythmic therapy as initial treatment for patients with atrial fibrillation. A total of three RCTs met the inclusion criteria (724 patients) and were used in the meta-analysis. The primary outcome of our meta-analysis was recurrence of atrial tachyarrhythmias. The secondary outcome evaluated serious adverse events of each therapy. Results The results showed a statistically significant reduction of recurrence of atrial tachyarrhythmic events in patients receiving cryoablation compared to anti-arrhythmic therapy [Risk Ratio (RR): 0.60, 95% CI (0.49, 0.72), P&lt;0.ehab724.03521, I2=0%]. There was no significant difference in serious adverse events between patients receiving cryoablation compared to patients receiving anti-arrhythmic therapy. [Risk Ratio (RR): 1.19, 95% CI (0.71, 2.00), P=0.52, I2=0%]. Conclusion Our meta-analysis showed that cryoablation therapy as an initial therapy is more efficacious than anti-arrhythmic therapy in patients with atrial fibrillation without an increased risk of serious adverse events. FUNDunding Acknowledgement Type of funding sources: None.

High‐Resolution Mapping and Ablation of Atrial Tachycardias Involving the Lateral Left Atrium

Background The lateral left atrium (LA) is often associated with atrial tachycardia (AT) because of its complex anatomy. We sought to characterize ATs associated with the lateral LA, including the posterolateral mitral isthmus (MI) and left atrial ridge. Methods and Results Twenty‐eight lateral LA‐associated ATs were mapped with high‐resolution mapping systems and entrainment pacing. The vein of Marshall was mapped with a 1.8‐Fr mapping catheter when possible. ATs were associated with the posterolateral MI in 18 ATs (14 perimitral, 3 small reentry, and 1 focal AT). All patients had undergone MI area ablation, and all ATs were successfully eliminated. During 27.0 (interquartile range, 10.5–40.0) months of follow‐up, all were free from any atrial tachyarrhythmias, with 3 patients on antiarrhythmics. Of 10 ATs involving the ridge or Marshall bundle, 3 were ridge related, 3 were Marshall bundle related based on vein of Marshall mapping, and 1 was a persistent left superior vena cava related AT. All 7 patients had undergone MI linear ablation. The critical isthmus was in the LA‐ridge junction or the LA‐Marshall bundle junction. Bidirectional conduction block between the LA and ridge or Marshall bundle was created. Two patients had the critical isthmus in the other area. The remaining patient had micro‐reentry in the ridge. All 10 ATs were terminated during ablation at the critical isthmus. During 12.0 (5.2–31.7) months of follow‐up, all were free from any atrial tachyarrhythmias, with 7 patients on antiarrhythmics. Conclusions Most ATs occurred after MI area ablation. An high resolution mapping‐guided approach is highly effective for identifying the mechanism.

Atrial fibrillation management during septal myectomy for hypertrophic cardiomyopathy: A systematic review

Introduction Atrial fibrillation is common in patients with hypertrophic cardiomyopathy, and significantly impacts mortality and morbidity. In patients with atrial fibrillation undergoing septal myectomy, concomitant surgery for atrial fibrillation may improve outcomes. Methods A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies reporting the outcomes of combined septal myectomy and atrial fibrillation surgery were included. Results A total of 10 observational studies were identified, including 644 patients. Most patients had paroxysmal atrial fibrillation. The proportion with prior unsuccessful ablation ranged from 0 to 19%, and preoperative left atrial diameter ranged from 44 ± 17 to 52 ± 8 mm. Cox–Maze IV (n = 311) was the most common technique used, followed by pulmonary vein isolation (n = 222) and Cox–Maze III (n = 98). Patients with persistent or longstanding atrial fibrillation more frequently received Cox–Maze III/IV. Ranges of early postoperative outcomes included: mortality 0 to 7%, recurrence of atrial tachyarrhythmias 4.4 to 48%, cerebrovascular events 0 to 1.5%, and pacemaker insertion 3 to 21%. Long-term data was limited. Freedom from atrial tachyarrhythmias at 1 year ranged from 74% to 96%, and at 5 years from 52% to 100%. Preoperative predictors of late atrial tachyarrhythmia recurrence included left atrial diameter >45 mm, persistent or longstanding preoperative atrial fibrillation and longer atrial fibrillation duration. Conclusion In patients with atrial fibrillation undergoing septal myectomy, the addition of ablation surgery adds low overall risk to the procedure, and likely reduces the risk of recurrent atrial fibrillation in the long term. Future randomised studies comparing septal myectomy with or without concomitant AF ablation are needed.