Effects of Acetyl-L-Carnitine on Cardiac Arrhythmias and Infarct Size in Ischemic-Reperfused Isolated Rat Heart

Abstract

Objective(s) This study aimed to examine whether acetyl-L-carnitine (ALC) was able to reduce cardiac arrhythmias and infarct size in the ischemic-reperfused isolated rat heart. Materials and Methods The isolated hearts were Mounted on a Langendorff apparatus then perfused by a modified Krebs-Henseleit solution during 30 min regional ischemia and 120 min reperfusion (control) or by enriched Krebs solution with 0.375, 0.75, 1.5 and 3 mM of ALC (treatment groups). The ECGs were recorded and analyzed to determine cardiac arrhythmias. The infarct size was determined by using a computerized planimetry package. Results During ischemia, all used concentrations of ALC decreased number and duration of ventricular tachycardia (VT), total number of ventricular ectopic beats (VEBs) (P<0.01), incidence of total ventricular fibrillation (VF) and the time spent for reversible VF (P<0.05). At the reperfusion phase, duration of VT, incidence of total VF and reversible VF were significantly lowered by ALC (P<0.05). In addition, infarct size significantly was decreased in all treated groups. In the control group, the infarct size was 23+/-3.1%, however, ALC (0.375, 0.75 and 3 mM) reduced it to 8.7 +/- 2.3, 5.3 +/- 1.4, and 8 +/- 2.9%, respectively (P<0.01). Conclusion Considering the results, it may be concluded that ALC has protective effects against cardiac ischemia-reperfusion (I/R) injuries by reduction of infarct size and arrhythmias in isolated rat heart. Among the potential cardioprotective mechanisms for ALC, increase in glucose oxidation and resulting reduced lactate production, reduction of toxic fatty acid metabolites and removing free radicals from the myocytes are more relevant.