Effects of hot shot [non cardioplegic blood based] on cardiac contractility and rhythm as parameters of myocardial protection in CABG surgery

To compare the effects of warm blood cardioplegia along with hot shot [non-cardioplegic blood based] at the end of ischemic time to warm blood cardioplegia without hot shot to assess resumption of effective electromechanical activity and need for internal electrical cardioversion as indicators of myocardial protection and preservation. Randomized control trial. The study was conducted at Armed Forces Institute of Cardiology [AFIC], Rawalpindi for a period of 10 months [March 2009 - Dec 2009]. Total 100 patients of coronary artery disease having coronary artery bypass grafting [CABG] surgery were equally and randomly divided into two groups using random numbers table. Group A [n=50], consisted of warm blood cardioplegia with non cardioplegic blood based hot shot and group B [n=50], consisted of warm blood cardioplegia only. The adequacy of myocardial protection techniques was assessed by noting the time interval [in seconds] between declamping of the ascending aorta and patient regaining electromechanical activity. Additional parameters were rhythm, use of internal cardiac defibrillation, inotropes, IABP requirement and ECG evidenced peri-op MI. Average age in group A was 56.98 +/- 9.47 years and in Group B it was 59.14 +/- 9.35 years. In group A there were 48 [96%] males and group B there were 43 [86%] males with p-value of 0.081. Comparison of preoperative variables of both the groups revealed no difference in cross clamp time [p=0.52], CPB time [p = 0.68] and endarterectomy [p=0.55]. The electromechanical activity [contractility of heart] returned within 7.53 +/- 2.09min in group A as compared to 9.81 +/- 2.6min in group B [p<0.001]. Significantly high frequency was observed for defibrillation [p=0.025], inotropic support [p=0.045] and IABP insertion [p=0.041] in group B as compared to group A. In CABG surgery the additional use of hot shot [non cardioplegic blood based] during cardiopulmonary bypass [CPB] is effective in myocardial protection and preservation by resuming early contractility of heart, benefit of no detrimental effects like dysrhythmias and less requirement of chemical or mechanical cardiac support