Faculty Bibliography

Algorithms designed to reduce the burden of right ventricular pacing are widely available in modern implantable pacing devices. To ensure safe and optimal utilization, understanding the properties of these algorithms as well as their possible unfavourable effects is essential. In this review, we discuss in detail the technical and clinical aspects of rhythm management algorithms and update on their significant recent modifications. In addition, we highlight possible adverse phenomena that may be induced by these different pacing algorithms intended to minimize pacing.

PURPOSE/OBJECTIVE:Elimination of pace-capture along pulmonary vein isolation (PVI) lesion sets reduces atrial fibrillation (AF) recurrence in catheter ablation of paroxysmal AF. Pacing from the RF ablation electrode during RF application is prevented within the CARTO electroanatomic mapping system (Biosense Webster, Inc.) due to theoretical safety considerations. We evaluated a method of pacing the distal ablation electrode during RF application in the CARTO system, thus avoiding repeated activation and inactivation of the pacing channel and facilitating immediate recognition of pace-capture loss. We investigated the safety, feasibility, and utility of simultaneous pace-ablate (SPA) during AF ablation with the CARTO-3 system and a contact-force sensing RF ablation catheter. METHODS:Safety of feasibility of SPA was evaluated in 250 patients undergoing first-time AF ablation. Frequency and regional distribution of pace-capture following PVI was evaluated in a cohort of 50 consecutive patients undergoing catheter ablation of paroxysmal AF. RESULTS:SPA was successfully performed in all 250 patients without adverse event. At least one pace-capture site was noted in 22 of 50 PAF patients (44%), and pace-capture following PVI was most common at anterior and superior left atrial sites. There were 2.0 ± 3.3 RF applications during pacing via the distal ablation electrode per patient, and all lesions sets were successfully rendered unexcitable. CONCLUSIONS:Pace-capture along the completed PVI lesion set remains common despite utilization of contact-force sensing RF ablation catheters and automated lesion annotation. Simultaneous pace-ablate in AF ablation using the CARTO system may be safely used to render atrial lesion sets unexcitable.

Introduction/UNASSIGNED:catheters in atrial fibrillation (AF) ablation. Methods/UNASSIGNED:catheter. A generalized estimating equation was used to compare index admission cost. Survey logistic regression was used to compare the incidence of inpatient readmission, direct-current cardioversion (DCCV), and repeat ablation. Multivariable analyses were adjusted for hospital clustering and demographic, procedural, hospital, and comorbidity characteristics. Results/UNASSIGNED:group. Conclusions/UNASSIGNED:catheter.

OBJECTIVES/OBJECTIVE:This study sought to investigate the effect of pacing mediated heart rate modulation on catheter-tissue contact and impedance reduction during radiofrequency ablation in human atria during atrial fibrillation (AF) ablation. BACKGROUND:In AF ablation, improved catheter-tissue contact enhances lesion quality and acute pulmonary vein isolation rates. Previous studies demonstrate that catheter-tissue contact varies with ventricular contraction. The authors investigated the impact of modulating heart rate on the consistency of catheter-tissue contact and its effect on lesion quality. METHODS:Twenty patients undergoing paroxysmal AF ablation received ablation lesions at 15 pre-specified locations (12 left atria, 3 right atria). Patients were assigned randomly to undergo rapid atrial pacing for either the first half or the second half of each lesion. Contact force and ablation data with and without pacing were compared for each of the 300 ablation lesions. RESULTS:Compared with lesion delivery without pacing, pacing resulted in reduced contact force variability, as measured by contact force SD, range, maximum, minimum, and time within the pre-specified goal contact force range (p < 0.05). There was no difference in the mean contact force or force-time integral. Reduced contact force variability was associated with a 30% greater decrease in tissue impedance during ablation (p < 0.001). CONCLUSIONS:Pacing induced heart rate acceleration reduces catheter-tissue contact variability, increases the probability of achieving pre-specified catheter-tissue contact endpoints, and enhances impedance reduction during ablation. Modulating heart rate to improve catheter-tissue contact offers a new approach to optimize lesion quality in AF ablation. (The Physiological Effects of Pacing on Catheter Ablation Procedures to Treat Atrial Fibrillation [PEP AF]; NCT02766712).