Introduction: The synthesized 18-lead electrocardiogram (ECG) (Nihon koden Co. Ltd.) has been reported to be useful. Recording of the posterolateral leads (V7 to V9 leads) is useful for making the diagnosis of posterior wall infarction. In this study, we examined whether a synthesized 18-lead ECG is useful for the diagnosis of posterior wall infarction.
Methods: This study was a retrospective observational study that was conducted in 196 of 363 patients with ST-elevation myocardial infarction (STEMI) who visited our institution between April 2012 and March 2016, and whose records of the synthesized 18-lead ECG were still available. The culprit lesion as identified by coronary angiography was analyzed, especially, in patients with ST elevation in the synthesized posterolateral leads. The end points were the incidence of major adverse cardiac events (MACE), number of hospital days, medical expenses, and the peak creatine kinase (CK) value.
Results: Among the 196 cases, 40 with ST elevation in the synthesized posterolateral leads were included for analysis. Of the 40 patients, the culprit coronary artery was the RCA in 24 cases (60.0%) (RCA Group), the LCX in 11 cases (27.5%) (LCX Group), and left anterior descending coronary artery (LAD) in 5 cases (12.5%) (p<0.001). Table 1 shows a comparison of the endpoints between the RCA Group and LCX Group.
Conclusions: In this study, the RCA was the most frequently identified culprit coronary artery in patients with posterior wall infarction. However, in patients with posterior wall infarction in whom the culprit coronary artery was the LCX, the number of hospital days was significantly higher. This result could have been influenced by the significantly smaller number of patients with ST segment elevation in the inferior wall leads in the LCX Group (72.7%) than in the RCA Group (100%) (P = 0.003). Our results indicate that the synthesized 18-lead ECG can improve the diagnostic accuracy for posterior wall infarction.