Angioplasty induced myocardial ischaemia prolongs the signal-averaged P-wave duration in single vessel coronary artery disease.

Abstract

Aims The P-wave duration (PWD) has been shown to prolong in conditions associated with elevated left ventricular end-diastolic and left atrial pressures, which also increase during transient coronary artery occlusions such as angioplasty. The aim of this study was to investigate the effects of angioplasty-induced myocardial ischaemia on signal averaged PWD in patients undergoing coronary angioplasty. Methods Eighty-four consecutive adult patients with single-vessel coronary artery disease undergoing elective coronary angioplasty were included. Duration of the P wave before and during coronary angioplasty were evaluated using signal averaged P-wave analysis. Patients were classified in groups according to the artery occluded, as left anterior descending (LAD) Group, right coronary artery (RCA) Group or Others Group (which included obtuse marginal, circumflex or diagonal). Results Patients included in the LAD, RCA and Others groups were similar with respect to clinical characteristics. The mean PWD at baseline was similar in all lesions (P>0.05), whereas mean PWD at inflation was significantly longer in LAD Group compared with RCA (126.1 +/- 9.5 ms vs 118.7 +/- 10.4 ms, P=0.007) and Others (126.1 +/- 9.5 ms vs 116.3 +/- 8.6 ms, P<0.001). The PWD during balloon inflation was significantly prolonged in all groups compared with baseline levels (LAD Group 126.1 +/- 9.6 ms vs 109.7 +/- 8.0 ms; RCA Group 118.7 +/- 10.4 ms vs 108.3 +/- 8.4 ms and Others Group 116.3 +/- 8.6 ms vs 109.7 +/- 6.0 ms, all P values <0.001). Conclusion Signal-averaged PWD significantly increases during single-vessel coronary angioplasty. This increase is more pronounced for LAD lesions. However, the clinical implications of P-wave prolongation during balloon angioplasty and the value of PWD as a measure of ischaemia remains to be clarified.