Abstract: AIM: To observe the effects of short-term fasting (STF) on myocardial energy metabolism and arrhythmia after myocardial ischemia/reperfusion (I/R) in rats. METHODS: 80 SD ratswere randomly divided into 5 groups: normal control group, I/R group, STF group, amiodarone group, combination group (STF +amiodarone) .The I/R model of SD rats was established by deligation left anterior descending coronary artery 30 min, reperfusion 120 min .The stan-dard limbs Ⅱlead electrocardiogram (ECG) was moni-tered and the occurrence condition of ventricular arrhythmia (VA) was recorded. The activities of cyto-chrome-oxydase(COX) and H⁺-ATPase were detected, after the myocardial mitochondria was extracted .The high energy phosphates (ATP, ADP and AMP) levels in myocardium were measured by HPLC.The activities of Na⁺/K⁺ -ATPase and Ca²⁺/Mg²⁺ -ATPase in myo-cardium tissues were determined.The protection was observed to myocardium, and the resultswere compared with the protection in amiodarone group.RESULTS: Compared with I/Rgroup, the onset of ventricular pre-mature contraction (VPC) was delayed markedly (P< 0.01) , the duration of VPC was shorted (P<0.01) , the incidences of ventricular tachycardia (VT) and ventricular fibrillation (VF) were decreased (P<0.05) in STF group.The activities of COX, H⁺ -AT-Pase, Na⁺/K⁺ -ATPase, Ca²⁺/Mg²⁺-ATPase and the contents of myocardial adenine nucleotide were de-creased signifcantly in I/R group.STF could increase the levelsof COX, ATPase and myocardial adenine nu-cleotide contents (P<0.01) .The myocardial protec-tive effects of the combination group was the best . CONCLUSION: STF has antiarrhythmic effect in rats, the protective action is related to the improvement of energy metabolism .

Key words: short-term fasting, ischemia reperfu-sion, arrhythmia, energy metabolism