Objective:To investigate the effects of balloon-induced acute ischaemia on p wave dispersion during percutaneous transluminal coronary angioplasty.Methods:76 patients with 1-vessel coronary artery disease were divided into myocardial ischaemia group and non-myocardial ischaemia group during intra-coronary balloon inflation.Myocardial ischaemia group was divided into the left anterior descending(LAD)

the left circumflex coronary artery(LCX) and the right coronary artery(RCA) groups.12-lead surface ECG before and during intra-coronary balloon inflation were recorded

p wave dispersion were calculated from 12-lead surface ECG.Results:① p wave dispersions were not significantly different among all groups before balloon inflation(37.5±4.97ms

36.7±5.70ms

36.9±4.59ms

36.4±4.76ms

P >0.05).②To be compared with the condition before balloon inflation

p wave dispersion during balloon inflation were significantly higher in the myocardial ischaemia groups(36.7±5.70 vs 46.3±4.21ms

36.9±4.59vs44.7±6.47ms

36.4±4.76vs44.8±5.88ms

P <0.001)

but not significantly different in the non-myocardial ischaemia group(37.5±4.97vs37.9±4.61ms

P >0.05).Conclusion:The prolongation of p wave dispersion may be a marker for severe acute myocardial ischaemia.