Device-based change in left ventricular shape: A new concept for the treatment of dilated cardiomyopathy

Abstract

Objective: We tested a unique new device, the Myosplint device (Myocor, Inc, Maple Grove, Minn), which is designed to change left ventricular shape, reduce left ventricular wall stress, and improve left ventricular systolic function. Methods: Heart failure was induced in 15 dogs over 27 days by rapid pacing (230 beats/min). Seven animals underwent sham surgery, and 8 animals received 3 transventricular Myosplint devices each. Myosplint devices were tightened to create a symmetric bilobular left ventricular shape and were adjusted to produce a calculated 20% reduction in wall stress. Hemodynamic, 2-dimensional, and 3-dimensional echocardiographic studies were recorded at baseline, immediately after Myosplint placement (acute change), and at 1 month after both groups had a reduced rate (190 beats/min) of pacing designed to maintain heart failure. Results: The Myosplint group had significant sustained improvements in left ventricular ejection fraction from baseline, to the acute change, to 1 month (19% ± 5%; 36% ± 8%; 39% ± 13%) and reductions of left ventricular end-systolic volumes (73 ± 9 mL; 34 ± 5 mL; 42 ± 12 mL) and end-systolic wall stress by 39% (341 ± 68 10 3 dynes · cm – 2 to 206 ± 28 10 3 dynes · cm –2) acutely and 31% (372 ± 83 10 3 dynes · cm –2 to 250 ± 40 10 3 dynes · cm –2) at 1 month. There were no significant changes in mitral regurgitation. Conclusion: Application of a Myosplint device to a dilated impaired left ventricle resulted in reduced wall stress and improved left ventricular systolic function that was sustained at 1 month. Device-based shape change is a promising new opportunity to treat patients with dilated cardiomyopathy.