Reshaping the remodelled left ventricle: a new concept

Objective: Based on the law of Laplace. transventricular tension members we re designed to diminish wall stress by changing the left ventricle (LV) glo bular shape to a bilobular one. thus reducing the ventricular wall radius o f 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). Treatmen t efficacy was assessed with sonomicrometric wall motion analysis Coupled w ith intraventricular pressure measurement. Preload increase was applied ste pwise with tension members in released and tightened position, Results: Tig htening of the tension members improved systolic function for CVP > 10 mmHg idP/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 +/- 14.8 vs. 13.6 +/- 2.7 mmHg. P < 0.001, for CVP > 10 mmHg: peak rat e 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 parame ter in this model of congestive heart failure. (C) 2001 Elsevier Science B. V. All rights reserved.