Methods for producing cardiomyocyte cells

A method for producing cardiomyocyte cells comprising:

• implanting a substrate within a heart such that a first portion of the substrate is in physical contact with an endocardium, and a second portion of the substrate is not in contact with the endocardium;
• maintaining the first portion of the substrate in contact with the endocardium for a time at least sufficient for trabecular fibers to form, the trabecular fibers extending between the endocardium and the second portion of the substrate, wherein the trabecular fibers include cardiomyocyte cells;
• cutting away the trabecular fibers from the endocardium;
• separating the first portion of the substrate from the endocardium;
• and
• removing the substrate and the attached trabecular fibers from the heart.

A method for producing cardiomyocyte cells comprising:

• positioning a substrate including an electrode within a heart such that the substrate is in physical contact with an endocardium, and the electrode is not in physical contact with the endocardium;
• maintaining the substrate within the heart for a time at least sufficient to form trabecular fibers extending between the endocardium and the electrode, wherein the trabecular fibers contain cardiomyocyte cells;
• cutting away the trabecular fibers from the endocardium;
• cutting away the trabecular fibers from the electrode;
• and
• removing the trabecular fibers from the heart.