YI-CHIH WANGCHIH-CHIEH YUChiu, Fu-ChunFu-ChunChiuSplett, VincentVincentSplettKlepfer, RuthRuthKlepferHilpisch, KathrynKathrynHilpischCHIA-TI TSAILING-PING LAIHWANG, JUEY-JENJUEY-JENHWANGJIUNN-LEE LIN2020-12-022020-12-022015-02-240008-6312https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921891702&doi=10.1159%2f000368795&partnerID=40&md5=25fe72d0c8b83ae752694acdfd9ac5c8https://scholars.lib.ntu.edu.tw/handle/123456789/524162https://www.scopus.com/record/display.uri?eid=2-s2.0-84921891702&doi=10.1159%2f000368795&origin=inward&txGid=980b64f4b3c3a1803da29d10321c9daeObjectives: We tested the acute effects of resynchronization in heart failure patients with a normal (>50%) left ventricular (LV) ejection fraction (HFNEF) and mechanical dyssynchrony. Methods: Twenty-four HFNEF patients (72 ± 6 years, 5 male) with mechanical dyssynchrony (standard deviation of electromechanical time delay among 12 LV segments >35 ms) were studied with temporary pacing catheters in the right atrium, LV, and right ventricle (RV), and high-fidelity catheters for pressure recording. Using selected atrioventricular (AV) intervals of 60, 90, 120, 150, and 180 ms to optimize transmitral flow during simultaneous biventricular pacing, the RV-LV (VV) interval was then evaluated at RV30, RV15, 0, LV15, LV30, and LV45 (RV or LV indicates which ventricle was paced first, the number indicates by how many ms). Results: During simultaneous pacing, longer AV intervals were associated with improved LV pressure-derivative minimums and increased aortic pressures (p < 0.05 vs. normal sinus rhythm). In the VV interval from RV30 to LV45, there was a graded increase in the aortic velocity time integral and a decrease in dyssynchrony during simultaneous or LV-first pacing (p < 0.05 vs. normal sinus rhythm). Conclusions: For HFNEF patients with mechanical dyssynchrony, acute simultaneous biventricular or LV-first pacing with longer AV intervals reduced mechanical dyssynchrony and improved diastolic and systolic hemodynamics. © 2015 S. Karger AG, Basel.enjournal article10.1159/000368795256126602-s2.0-84921891702