In order to observe the differences of ararrhythmias characteristics between ischemic and reperfusion period, and correlationship between occlusion and reperfusion arrhythmias, the left anterior descending(LAD) coronary artery was occluded for 20 minutes and reperfused for 10 minutes in 24 anesthetized cats.

The results were as follows;

1) After ligation of LAD coronary artery, the R wave, S-T segment and T wave of epicardial EKG were elevated to reach maximum level at 5-10 minutes.

2) During reperfusion, the changes of R wave, S-T segment, and T wave of epicardial EKG were not significant.

3) The incidence of arrhythmias at early phase and late phase of occlusion period were 41.6% and 100% respectively.

The ischemic arrhythmia score was 2.38±1.61 and incidence of ventricular tachycardia(VT) was 66%

4) The incidence of VT and VF during reperfusion was 100% and 62.5% respectively. The reperfusion arrhythmia score was 5.88±1.72.

5) The two morphologies of ventricular arrhythmias were observed at occluson and reperfusion period.

6) The disparities between occlusion and reperfusion arrhythmias were observed.

7) The cats with shorter R-R internal and/or lower systolic left ventricualr pressure had the higher incidence of VF.

In summary, although the morphology of occlusion ventricular arrhythmias was similar to that of reperfusion ventricular arrhythmias, the lack of correlation between reperfusion VF and ischemic arrhythmias was observed. So we suggest that further studies which provide the different mechanisms involved in occlusion and reperfusion arrhythmias were needed.