ST elevation measurements differ in patients with inferior myocardial infarction and right ventricular infarction

Purpose: Few studies specify the methods used to measure ST-segment elevation (STE). We therefore assessed differences in electrocardiography results depending on STE measurement methods for patients with inferior acute myocardial infarction (MI) and right ventricular infarction. Methods: This study was a retrospective analysis. The STE group consisted of 88 patients consecutively admitted to the emergency department with inferior ST elevation MI associated with occlusion of right coronary artery or left circumflex coronary artery who underwent primary percutaneous coronary intervention. The control group consisted of 109 patients with non-ST elevation MI who had occlusion of right coronary artery or left circumflex coronary artery and underwent percutaneous coronary intervention. Measurements were performed at the J point and 60 milliseconds later for limb lead and right precordial V ₄ lead (V4R). The criterion of at least 1-mm STE in 2 consecutive leads was applied, and the diagnostic accuracy of V4R was calculated. Results: In the STE group, the measurements 60 milliseconds after the J point were significantly higher than measurements at the J point at the II, III, aVF, and V4R leads. In the control group, only the measurements at lead I differed significantly. There was a 5% difference in diagnostic sensitivity depending on the measuring points in the STE group, a 1% to 3% difference in the control group, and a 10% to 11% difference at the V4R lead. Conclusion: In patients with inferior MI, STE depends on the method of measurement, indicating a need for the standardization of measurements.