Circulation: Arrhythmia and Electrophysiology On the Beat May 2018

Paul Wang: Welcome to the monthly podcast, On the Beat, for Circulation: Arrhythmia and Electrophysiology. I'm Dr. Paul Wang, editor-in-chief, with some of the key highlights from this month's issue.

In our first study, Filip Plesinger and associates examined whether a computerized analysis of the body surface 12-lead ECG can be used to measure the ventricular electrical activation delay as a predictor of heart failure or death following resynchronization therapy in a MADIT-CRT trial.

The authors found that left bundle branch block patients with baseline ventricular electrical activation delay less than 31.2 milliseconds had a 35% risk of MADIT-CRT endpoints, while patients with ventricular electrical activation delay greater than or equal to 31.2 milliseconds had a 14% risk, P value of less than 0.001.

The hazard ratio for predicting primary endpoints in patients with low ventricular electrical activation delay was 2.34 with a P value of less than 0.01. However, ventricular electrical activation delay was not predicted in patients with right bundle branch block or IVCD.

In our next study, Karl-Heinz Kuck and associates examined the predictors of long-term clinical outcomes after catheter ablation of atrial fibrillation in 750 patients in the FIRE AND ICE Trial. Using propensity score stratification methods to count for differences in baseline characteristics between sexes, the authors found that female sex with a hazard ratio of 1.37, P equals 0.01, and prior direct current cardioversion with a hazard ratio of 1.40, P equals 0.013 were independently associated with atrial fibrillation recurrence.

Female sex with hazard ratio of 1.36, P value of 0.035 and hypertension with a hazard ratio of 1.48, P value of 0.013 independently predicted cardiovascular rehospitalization. A longer history of atrial fibrillation with a hazard ratio of 1.03, P value of 0.039 increased the rate of repeat ablation.

After propensity score adjustment, women continued to have higher rates of primary efficacy failure with adjusted hazard ratio of 1.51, P less than 0.05 and cardiovascular rehospitalization with a hazard ratio of 1.40, P less than 0.05.

In the next study, Laura Bear and associates examined the reliability of inverse electrocardiographic mapping of cardiac electrical activity from recorded body surface potentials. In five anesthetized closed-chest pigs, torso and ventricular epicardial potentials were recorded simultaneously during sinus rhythm, epicardial, and endocardial ventricular pacing. Two approaches, coupled finite/boundary element methods and a meshless approach based on the method of fundamental solutions, were compared.

The authors found that inverse mapping underestimated epicardial potentials more than twofold, P less than 0.0001. Mean correlation coefficients for reconstructed epicardial potential distributions ranged from 0.60 to 0.64 across all methods. Epicardial electrograms were recovered with reasonable fidelity at approximately 50% of the sites, but variation was substantial.

General activation spread was reproduced with a mean correlation coefficient of 0.72 to 0.78 for activation time maps with spatio-temporal smoothing. Epicardial foci were identified with a mean location error approximately 16 millimeters. Inverse mapping with method of fundamental solutions was better than coupled finite/boundary element methods.

The authors concluded that spatio-temporal variability of recovered electrograms may limit the resolution, with implications for accuracy of arrhythmia localization.

In the next study, Pejman Raeisi-Giglou and colleagues examined the incidence of pulmonary vein stenosis in 10,368 patients undergoing atrial fibrillation ablation from 2000 to 2015. Computed tomography scans were performed three to six months after the procedures. Severe pulmonary vein stenosis was observed in 52 patients, or 0.5%. The left superior pulmonary vein represented 51% of all severely stenosed veins.

Percutaneous interventions were performed in 43 patients, and complications occurred in five, including three pulmonary vein ruptures, one stroke and one phrenic injury. Over a median follow-up of 25 months, 41, or 79%, of patients remained arrhythmia-free.

In our next paper, Koichi Nagashima and associates compared hot balloon ablation and cryoballoon ablation in a 165 consecutive patients who underwent initial atrial fibrillation catheter ablation. Of the 165 patients, 74 propensity score-matched patients equally divided between hot balloon ablation and cryoballoon ablation were studied.

Patients' characteristics included age, sex, body mass index, atrial fibrillation subtype, CHA2DS2-VASc score, and left atrial dimension were similar between the two groups. 52% of the hot balloon ablation patients required touch-up with radiofrequency ablation for residual/dormant pulmonary vein condu...