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

Objective: We tested a unique new device, the Myosplint device (Myocor, Inc , Maple Grove, Minn), which is designed to change left ventricular shape, r educe left ventricular wall stress, and improve left ventricular systolic f unction. 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 receiv ed 3 transventricular Myosplint devices each. Myosplint devices were tighte ned to create a symmetric bilobular left ventricular shape and were adjuste d to produce a calculated 20% reduction in wall stress. Hemodynamic, 2-dime nsional, and 3-dimensional echocardiographic studies were recorded at basel ine, immediately after Myosplint placement (acute change), and at 1 month a fter both groups had a reduced rate (190 beats/min) of pacing designed to m aintain heart failure. Results: The Myosplint group had significant sustained improvements in left ventricular ejection fraction from baseline, to the acute change, to 1 mon th (19% +/- 5%; 36% +/- 8% ; 39% +/- 13%) and reductions of left ventricula r end-systolic volumes (73 +/- 9 mL; 34 +/- 5 mL; 42 +/- 12 mL) and end-sys tolic 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 ve ntricle resulted in reduced wall stress and improved left ventricular systo lic function that was sustained at 1 month. Device-based shape change is a promising new opportunity to treat patients with dilated cardiomyopathy.