Some form or other of chemical cardioplegia is used by most cardiac surgeons today as a means of intra-operative myocardial protection. Innumerable clinical papers supporting each of these solutions have emerged but actual experimental evidence of their efficacy is scarce. Experimental models were developed at the University Hospital, Kuala Lumpur to facilitate the testing of commonly used cardioplegic solutions in vivo and in vitro. This paper summarises the experimental and clinical data obtained as regards biochemical and electronmicroscopic changes. From the results, it can be concluded that the solution used at the University Hospital was safe and effective. An extension of the use of these experimental models could perhaps delineate the exact composition required to constitute an ideal cardioplegic solution.