Effect of Coronary Artery Occlusion and Reperfusion on Signal Average Electrocardiography in Cats

Chung, Moon Ho; Lee, Tae Il; Kang, Sung Ho; Shin, Dong Gu; Kim, Young Jo; Shim, Bong Sup

Abstract

BACKGROUND
Recently, a lower incidence of late potentials has been reported in patients with acute myocardial infarction after successful thrombolysis when compared with conventionally treated patients. In another recent study, however, no significant effect of thrombolytic therapy on any abnormal signal average electrocardiography was found at 13 days after acute myocardial infarction. The present study was designed to determine the prognostic significance of the signal average electrocardiography and to evaluate the possible value of this technique as a noninvasive tool for monitoring of coronary occlusion and reperfusion.
METHODS
Signal averaging was performed by using a signal average electrocardiography with bidirectional filterings before coronary artery occlusion, at 5 minutes after coronary occlusion and on reperfusion in 20 cats. Three of them died due to malignant ventricular arrhythmia during reperfusion. In all cats, approximately 250 beats were averaged. All data were analysed at filter frequency 25 to 250Hz, 40 to 250Hz and 80 to 250Hz. The following quantitative high resolutional electrocardiographic variables were calculated by computer : 1) filtered total QRS duration, 2) duration of HFLA(high frequency low amplitude) signals under 40uV, 3) RMS voltage of terminal 40ms, 4) mean Voltage of terminal 40ms, 5) average noise voltage.
RESULTS
At the filter frequency of 40 to 250Hz and 80 to 250Hz, the filtered QRS duration and duration of HFLA signals 40uV were significantly prolonged at 5 minutes after coronary artery occlusion than before coronary occlusion(p<0.01). At the filter frequency of 40 to 250Hz and 80 to 250Hz, the RMS voltage(terminal 40ms) and mean voltage(terminal 40ms) were significantly prolonged at 5 minutes after coronary artery occlusion than before coronary occlusion(p<0.01, p<0.01 respectively). At the filter frequency of 80 to 250Hz, the filtered QRS duration and at the filter frequency of 25-250Hz, the duration of HFLA signals at 40uV were significantly shortened during reperfusion than at 5 minutes after coronary artery occlusion(p<0.01, p<0.05 respectively). At the filter frequency of 40 to 250Hz and 80 to 250Hz, the RMS voltage(terminal 40ms) and mean Voltage(terminal 40ms) were significantly shortened during reperfusion than at 5 minutes after coronary artery occlusion(p<0.01, p<0.01 respectively). There was no significant change of the filtered QRS duration, duration of HFLA signals 40uV,RMS voltage(terminal 40ms) and mean Voltage(terminal 40ms) after reperfusion compared with those of control at the filter frequency of 25 to 250Hz, 40 to 250Hz and 80 to 250Hz respectively.
CONCLUSION
These results suggest that the signal average electrocardiography could be a valuable tool for monitoring the state of coronary artery occlusion and reperfusion.