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A354 JACC April 1, 2014 Volume 63, Issue 12 Arrhythmias and Clinical EP SINGLE-SITE PACING IS ASSOCIATED WITH SUPERIOR ATRIAL MECHANICS COMPARED TO DUAL-SITE PACING IN DOGS Poster Contributions Hall C Saturday, March 29, 2014, 3:45 p.m.-4:30 p.m. Session Title: Innovations in Device Management in AF: Devices Abstract Category: 8. Arrhythmias and Clinical EP: Devices Presentation Number: 1142-109 Authors: Mirza Nubair Ahmad, Indrajit Choudhuri, Bijoy K. Khandheria, Khawaja Afzal Ammar, Aurora Cardiovasc Svcs, Aurora Sinai/St. Luke’s Med Ctrs, Univ Wisconsin Sch Med and Public Health, Milwaukee, WI, USA Background: Although traditionally the right atrium is paced via a lead in the right atrial appendage (RAA), concern has been raised that doing so can cause atrial dyssynchrony, analogous to ventricular dyssynchrony from right ventricular apical pacing. This dyssynchrony has been postulated to result in adverse atrial mechanics, atrial fibrillation and heart failure. Two-dimensional speckle tracking echocardiography (2DSTE) provides an opportunity to evaluate atrial mechanics. We hypothesized that dual-site pacing (DSP) will result in superior atrial mechanics in a dog model. Methods: A group of anaesthetized dogs (n=7, mean weight 29.4 ± 1.4 kg) under mechanical ventilation (6-8 L/min oxygen) were studied with 2DSTE, first in normal sinus rhythm (NSR), then by single-site pacing (SSP) with epicardial leads at different atrial sites, including RAA, sinus node, Bachmann’s bundle (BB), coronary sinus ostium (CSO) and perimitral (low) lateral left atrium (LLL). For dual-site pacing, combinations of RAA with BB, RAA with CSO and RAA with LLL were studied. Results: NSR resulted in the best atrial function, followed by SSP and then DSP (Table), although this trend was not significant in all parameters. The best SSP by stroke volume was via CSO. The best DSP by stroke volume was via RAA with LLL. Conclusion: Single-site pacing was associated with superior atrial mechanics, suggesting that dual-site pacing, instead of producing atrial resynchronization, may produce opposing wavefronts that cancel each other.
