Effect of combined cold and pharmacological ischaemic cardioplegia on myocardial intrinsic sympatho-adrenergic system during coronary bypass surgery.

The effect of combined cold and pharmacological ischaemic cardioplegia on the structural integrity and the degree of the functional activity of the inbuilt intrinsic sympatho-adrenergic nervous system was studied by means of fluorescence microscopy of atrial myocardial biopsies obtained in the course of coronary bypass surgery on 8 consecutive patients. The specimens were taken 1) before starting extracorporeal circulation (controls), and 2) at decannulation (i.e. after cold cardioplegic ischaemic asystole and subsequent coronary reperfusion). The cardioplegia was induced by perfusing the coronary arteries via the aortic root with cold "cardioplegic solution" after starting extracorporeal circulation, venting the left ventricle and cross-clamping the ascending aorta. The specimens were processed for semi-quantitative fluorescence histochemical analysis. No changes were observed. Thus, it is concluded that the procedure of the combined cold and pharmacological ischaemic cardioplegia obviously preserves well the neural noradrenalin of the heart, a vital means of compensating for decreasing myocardial contractility. As the clinical parallelism, all patients made a smooth convalescence.