Adenosine protects against hypoxic injury at hypothermia in guinea pig papillary muscles

Cardiac purinergic signalling in health and disease

This review is a historical account about purinergic signalling in the heart, for readers to see how ideas and understanding have changed as new experimental results were published. Initially, the focus is on the nervous control of the heart by ATP as a cotransmitter in sympathetic, parasympathetic, and sensory nerves, as well as in intracardiac neurons. Control of the heart by centers in the brain and vagal cardiovascular reflexes involving purines are also discussed. The actions of adenine nucleotides and nucleosides on cardiomyocytes, atrioventricular and sinoatrial nodes, cardiac fibroblasts, and coronary blood vessels are described. Cardiac release and degradation of ATP are also described. Finally, the involvement of purinergic signalling and its therapeutic potential in cardiac pathophysiology is reviewed, including acute and chronic heart failure, ischemia, infarction, arrhythmias, cardiomyopathy, syncope, hypertrophy, coronary artery disease, angina, diabetic cardiomyopathy, as well as heart transplantation and coronary bypass grafts.

Adenosine instead of supranormal potassium in cardioplegia: it is safe, efficient, and reduces the incidence of postoperative atrial fibrillation. A randomized clinical trial

OBJECTIVE

We aimed to evaluate the efficacy and safety of a cold crystalloid cardioplegic solution with adenosine (1.2 mmol/L) instead of supranormal potassium.

METHODS

Sixty low-risk patients scheduled for elective coronary artery bypass grafting (CABG) were randomized to receive standard cold crystalloid hyperkalemic cardioplegia (hyperkalemic group) or normokalemic cardioplegia in which supranormal potassium was replaced with 1.2 mmol/L adenosine (adenosine group). End points were postoperative release of troponin T and creatine kinase MB, hemodynamics measured by PiCCO arterial thermodilution catheters, perioperative release of markers of endothelial activation and injury, and clinical course.

RESULTS

The adenosine group had a significantly shorter time to arrest than did the hyperkalemic group (mean ± standard deviation, 11 ± 5 vs 44 ± 18 seconds; P < .001). Three hearts in the adenosine group were probably not adequately drained and received additional hyperkalemic cardioplegia to maintain satisfactory cardioplegic arrest. There were no differences between groups with respect to perioperative release of markers of endothelial activation or injury and no differences between groups in postoperative release of troponin T or creatine kinase MB. Postoperative hemodynamics including cardiac index were similar between groups. The incidence of postoperative atrial fibrillation was significantly lower in the adenosine group than in the hyperkalemic group (4 vs 15; P = .01).

CONCLUSIONS

Adenosine instead of hyperkalemia in cold crystalloid cardioplegia is safe, gives more rapid cardiac arrest, and affords similar cardioprotection and maintenance of hemodynamic parameters, together with a marked reduction in the incidence of postoperative atrial fibrillation.