Europace Advance Access published online on October 11, 2007
Europace, doi:10.1093/europace/eum218
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Single-site ventricular and biventricular pacing: investigation of latest depolarization strategy
1 Departments of Surgery and Biomedical Engineering, University of Minnesota, B172 Mayo, MMC 107, 420 Delaware Street SE, Minneapolis, MN 55455, USA; 2 Medtronic, Inc., 7000 Central Avenue NE, Minneapolis, MN 55432-3576, USA; 3 Broward General Medical Center, 1625 SE 3rd Avenue, Suite 610, Fort Lauderdale, FL 33316, USA; 4 CardioThoracic Centre, Liverpool NHS Trust, Thomas Drive, Liverpool L14 3PE, UK; 5 Medtronic, Inc., 8299 Central Avenue NE, MS P120, Minneapolis, MN 55432, USA; 6 Department of Surgery, University of Minnesota, B172 Mayo, MMC 107, 420 Delaware Street SE, Minneapolis, MN 55455, USA
Aims: Cardiac resynchronization therapy with biventricular pacing has proved beneficial in symptomatic heart failure patients, yet the effects in patients with structurally normal hearts remain unknown. We hypothesized that, in an acute swine model with normal anatomy and function, single-site right ventricular (RV) pacing would better preserve haemodynamic function and electrical activation compared to biventricular pacing.
Methods: Endocardial single-site pacing was performed in anesthetized swine (n = 7) from the RV septum and RV apex. Biventricular pacing was performed using an epicardial left ventricular (LV) lead and a RV lead. High-resolution, non-contact mapping was employed to record LV activation sequences simultaneously with haemodynamic data after 5 min of consistent capture.
Results: All pacing interventions significantly prolonged QRS and total endocardial activation durations (P < 0.05) compared to intrinsic activation. Biventricular pacing with the RV apex lead significantly impaired LV systolic mechanics (dP/dtmax, max LV pressure; P < 0.05), and reduced LV relaxation to the greatest extent (dP/dtmin, P = ns). Right ventricular septal pacing conserved function better than other pacing interventions (P = ns) and elicited an intrinsic electrical activation sequence.
Conclusion: In intact, synchronous hearts, acute biventricular pacing resulted in systolic dysfunction and abnormal LV electrical activation.
Key Words: Cardiac resynchronization therapy, Electrophysiology, Haemodynamics, Non-contact mapping
* Corresponding author. Tel: +1 612 624 7912; fax: +1 612 624 2002.E-mail address: iaizz001{at}umn.edu
Manuscript submitted 30 April 2007. Accepted after revision 3 September 2007.