The predominant method of myocardial protection during cardiac surgery is hyperkalaemic cardioplegia, inducing depolarised arrest. Since its development in the 1970s, the only real change has been to alter the vehicle to blood. Although blood cardioplegia was shown to be 'superior' to crystalloid cardioplegia, this advantage is marginal and might explain the continuous use of crystalloid cardioplegia by some surgeons. To achieve significant improvements in cardioplegic protection, more radical and conceptual changes in the solution, such as those potentially achieved by 'polarised' arrest, should be explored.