-Original-

Clinical Significance of Synthesized Posterior/Right-Sided Chest Lead Electrocardiograms in Patients with Acute Chest Pain

Takao Katoh¹, Akira Ueno², Keiji Tanaka², Jiro Suto³ and Daming Wei⁴

¹Division of Cardiology, Hepatology, Geriatrics, and Integrated Medicine, Department of Internal Medicine, Graduate School of Medicine, Nippon Medical School
²Coronary Care Unit, Nippon Medical School Hospital
³Nihon Kohden, Co. Ltd., Tokyo
⁴Graduate School of Information System, the University of Aizu

Background: 12-lead electrocardiograms (ECGs) provide insufficient information for the accurate diagnosis of posterior and/or right ventricular acute myocardial infarction (AMI) in patients with acute chest pain. Posterior chest leads (V7-V9) and/or right-sided precordial leads (V3R-V5R) provide important information from those specific areas, but these additional ECGs are not routinely recorded because of the time-consuming procedure involved. The purpose of the present study was to evaluate a newly developed system to synthesize these 6 additional lead ECGs non-invasively using standard 12-lead ECG information.
Patients and Methods: Thirty patients (25 men, 5 women; mean age: 65 ± 11 years) complaining of acute chest pain were enrolled. Standard 12-lead and V3R, V4R, V5R, V7, V8, V9 lead ECGs were successively recorded and compared with synthesized ECGs mathematically derived from standard 12-lead signals.
Results: The synthesized and actual ECG waveforms were almost identical, and there were significant correlations in ECG variables, including the P, QRS, and T waves (correlation coefficients about total 1-cycle signals: 0.97 in V3R; 0.93 in V4R; 0.88 in V5R; 0.98 in V7; 0.92 in V8; and 0.88 in V9, p<0.001). Both in patients with AMI (N=16) and in patients with ST elevation at the extended leads (N=8), significant correlations were also found (correlation coefficients were over 0.88 at all leads, p<0.001). The reproducibility of the ST segment was as good as that of the other ECG variables, even in patients with significant ST elevation due to posterior and/or right ventricular AMI.
Conclusion: Synthesized posterior and right-sided precordial lead ECGs appear to be highly reliable and useful in the rapid diagnosis of AMI, especially in the early detection of posterior and/or right ventricular involvement, thereby alleviating patient distress.

J Nippon Med Sch 2011; 78: 22-29

Keywords
synthesized electrocardiogram, posterior chest leads, right-sided chest leads, acute myocardial infarction

Correspondence to
Takao Katoh, MD, PhD, Division of Cardiology, Hepatology, Geriatrics and Integrated Medicine, Department of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan
tkkt@nms.ac.jp

Received, July 26, 2010
Accepted, November 1, 2010