Effect of passive cardiac containment on ventricular synchrony and cardiac function in awake dogs.
OBJECTIVE
Passive restraint of the left ventricle (LV) has been shown to have beneficial effects on acute hemodynamics and reverse remodeling in both animal and human models. The goals of this study were to test whether a left ventricular support device (LVSD) improves LV synchrony and/or affects cardiac performance.


METHODS
Ten dogs were chronically instrumented to measure hemodynamics and LV volume (sonomicrometry). Congestive heart failure (CHF) was induced by repeated intracoronary microembolization via a chronically implanted coronary catheter. The LVSD was implanted after establishment of CHF in five animals, and five animals were observed as controls. All animals were then observed for 8 weeks. A mathematical model to measure LV synchrony was used to evaluate LV motion over time.


RESULTS
Mean arterial pressure and LV pressures was significantly increased after LVSD therapy, and LV pressure-volume relationships were shifted leftwards, although no change was seen in ejection fraction, end-systolic elastance, or LV dP/dt versus control. There was no significant change in diastolic function in LVSD animals compared with control animals. End-diastolic volumes were reduced by 15% after 8 weeks with LVSD treatment, versus an increase of 8% in control animals (p<0.05). Synchrony was significantly improved with LVSD therapy compared with control (9% vs 76% of baseline) in 1 of 11 ventricular dimension axes (Anterior-Apex).


CONCLUSIONS
LVSD therapy provided only minimal improvement in ventricular synchrony and partially improved hemodynamics. Further study into mechanisms of benefit are warranted.
George
Isaac
I
Department of Surgery, Division of Cardiothoracic Surgery, Columbia University, College of Physicians and Surgeons, New York, NY, United States.
Cheng
Yanping
Y
Yi
Geng-Hua
GH
He
Kun-Lun
KL
Li
Xiaolong
X
Oz
Mehmet C
MC
Holmes
Jeffrey
J
Wang
Jie
J
D000818:Animals; D001794:Blood Pressure; D004285:Dogs; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D006339:Heart Rate; D006353:Heart-Assist Devices; D013318:Stroke Volume; D014463:Ultrasonography; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling