title: Effects of timing on ventriculoarterial coupling and mechanical efficiency during intraaortic balloon pumping.
abstract: To evaluate the effects of deflation timing of an intraaortic balloon (IAB) on ventriculoarterial (VA) coupling and left ventricular (LV) mechanics, we assessed contractility: Emax (mmHg/ml); VA coupling: Ea/Ees; myocardial oxygen consumption: LV pressure-volume area (PVA); and energy efficiency: external work (EW)/PVA during IAB pumping, using four different timing intervals of IAB deflation in eight dogs weighing 19.8 +/- 3.8 kg. In the conventional timing group (G-conv), the IAB was deflated before LV systole. In the real time group (G-1, 2, 3), the IAB was deflated during isovolumic contraction (ICP), and the group was subdivided into three groups based on time of deflation: G-1 at the onset of ICP, G-2 at the midpoint of ICP, and G-3 at the end of ICP. Percent changes in values with IAB compared to those without assist were calculated. Based on the results, IAB deflation during ICP reduces LV end-systolic pressure and significantly optimizes VA coupling and LV efficiency during IAB support, compared with conventional timing.
authors.affiliation: Department of Cardiothoracic Surgery, School of Medicine, Tokyo Medical and Dental University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Sakamoto
authors.forename: A
authors.initials: A
authors.lastname: Suzuki
authors.forename: S
authors.initials: S
authors.lastname: Kazama
authors.forename: S
authors.initials: S
authors.lastname: Komatsu
authors.forename: S
authors.initials: S
authors.lastname: Sasaki
authors.forename: Y
authors.initials: Y
authors.lastname: Shoji
mesh_terms: D000818:Animals; D001158:Arteries; D001696:Biomechanical Phenomena; D004285:Dogs; D005069:Evaluation Studies as Topic; D006352:Heart Ventricles; D006439:Hemodynamics; D007423:Intra-Aortic Balloon Pumping / Q000295:instrumentation / Q000379:methods*; D013599:Systole; D013997:Time Factors; D016277:Ventricular Function, Left