Body surface potential mapping improves detection of ST segment alteration during percutaneous coronary intervention

Background: The 12-lead electrocardiogram underestimates ST segment alteration in acute coronary syndromes compared with multi-lead body surface mapping. We assessed whether 80-lead mapping would improve detection of ST alteration during percutaneous coronary intervention. Methods: Simultaneous maps and 12-lead electrocardiograms were recorded pre-procedure, during balloon inflation and post-procedure from patients undergoing elective intervention to native coronary arteries. Recordings were obtained from 39 inflations (19 patients). All arteries were successfully stented. Results: Mean ‘lead specific’ ST alteration (the difference in ST elevation/depression between pre-procedure and inflation recordings in the lead showing maximal ST alteration) was greater on the map than on electrocardiogram, both for ST elevation (0.16±0.02 vs. 0.06±0.01 mV; p<0.001) and ST depression (0.11±0.017 vs. −0.03±0.006 mV; p<0.001). During first inflations (n=19), mean lead specific ST elevation and depression on map were greater than on electrocardiogram (0.20±0.034 vs. 0.07±0.015 mV; p<0.001 and 0.11±0.029 vs. 0.03±0.009 mV; p=0.001, respectively). Mapping detected greater summated ST elevation and depression during inflation than electrocardiogram (0.04±0.005 vs. 0.021±0.003 mV; p<0.001 and 0.026±0.004 vs. 0.011±0.002 mV; p<0.001, respectively). Qualitative analysis of maps and electrocardiograms showed that 21/39 (53.8%) maps recorded during inflation met criteria for myocardial ischaemia compared with 7/39 (17.9%) electrocardiograms (p<0.001). Conclusion: Body surface mapping compared with the 12-lead electrocardiogram improves detection of myocardial ischaemia during intervention.