Evaluation of the phase-plane ECG as a technique for detecting acute coronary occlusion

Objective: To evaluate the phase plane (PP) ECG as a method for detecting acute coronary occlusion (ACO). Background: Balloon inflation in a coronary artery during PTCA produces acute myocardial ischemia. The sensitivity of the standard ECG for detecting ACO is approximately 50%, depending on the number of leads recorded. Methods: The standard ECG signals of 18 patients (91 leads), undergoing PTCA were sampled and converted to digital data, prior to, and during acute coronary occlusion. PPs were constructed by projecting the ECG signals and their first derivatives onto a two-dimensional plane. Standard ECG signals and PPs, prior to ACO, were compared to their respective recordings and PPs during ACO. Results: Using the standard ECG analysis, the acute occlusion was detected in 39 of 91 leads (43%), and in 15 of 18 patients (83%), whereas using the PP analysis it was detected in 82 of 91 leads (90%), and in all 18 patients (100%) (P<0.001, for leads). The median number of leads per patient demonstrating standard ECG changes was 2.0, whereas for the PP analysis it was 5.5 (P<0.001). The specificity of the PP method was 83.5%. Conclusions: The sensitivity of the PP method for detecting ACO during PTCA was superior to that of the standard ECG analysis. A smaller lead system is required to detect changes of ACO, during PTCA, when the PP method is used. The PP method is simple, low-priced, and may serve to detect acute myocardial ischemia in a number of clinical settings.