Reshaping the remodelled left ventricle: a new concept.
OBJECTIVE
Based on the law of Laplace, transventricular tension members were designed to diminish wall stress by changing the left ventricle (LV) globular shape to a bilobular one, thus reducing the ventricular wall radius of curvature. This concept was tested in a model of congestive heart failure.


METHODS
Seven calves were used for the study (74.3+/-4.2 kg). Treatment efficacy was assessed with sonomicrometric wall motion analysis coupled with intraventricular pressure measurement. Preload increase was applied stepwise with tension members in released and tightened position.


RESULTS
Tightening of the tension members improved systolic function for CVP>10 mmHg (dP/dt: 828+/-122 vs. 895+/-112 mmHg/s, P=0.019, for baseline and 20% stress level reduction respectively; wall thickening: 11.6+/-1.5 vs. 13.3+/-1.7%, P<0.001) and diastolic function (LV end-diastolic pressure: 15.9+/-4.8 vs. 13.6+/-2.7 mmHg, P<0.001, for CVP>10 mmHg; peak rate of wall thinning: -12.2+/-2.2 vs. -14+/-2.3 cm(2)/s, P<0.001 and logistic time constant of isovolumic relaxation: 48.4 +/-10.9 vs. 39.8+/-9.6ms, P<0.001, for CVP>5 mmHg).


CONCLUSIONS
This less aggressive LV reduction method significantly improves contractility and relaxation parameters in this model of congestive heart failure.
Mueller
X M
XM
Clinic for Cardiovascular Surgery, CHUV (Centre Hospitalier Universitaire Vaudois), CH-1011 Lausanne, Switzerland. xavier.mueller@chuv.hospvd.ch
Tevaearai
H T
HT
Tucker
O
O
Boone
Y
Y
von Segesser
L K
LK
D000818:Animals; D002306:Cardiac Volume / Q000502:physiology*; D002417:Cattle; D006333:Heart Failure / Q000503:physiopathology / Q000601:surgery*; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery*; D006439:Hemodynamics / Q000502:physiology; D009200:Myocardial Contraction / Q000502:physiology; D013599:Systole / Q000502:physiology; D020257:Ventricular Remodeling / Q000502:physiology*