Isolated cardiomyocytes are a prerequisite to study the biology of cardiomyocytes. Efficient isolation is difficult, as these cells adhere firmly together in the heart and do not divide. Therefore, any experiment is restricted to the amount of calcium-tolerant, rod-shaped cardiomyocytes that can be initially isolated from the heart. This chapter gives detailed instructions on how ventricular cardiomyocytes can be isolated from an intact adult heart. The method is based on the principle of calcium-free perfusion with collagenase supplementation to disrupt cell-cell contacts in the heart, isolation and purification of cardiomyocytes from other cell types, and, finally, re-establishing a physiological cellular calcium concentration. The chapter also summarizes some commonly used adaptations to isolate cardiomyocytes from species different from rat.
