Shinobu Isomura

Correlation between body surface isopotential maps and left ventriculograms in patients with old inferoposterior myocardial infarction

In 24 patients with old inferoposterior myocardial infarction, body surface isopotential maps were compared with left ventriculographic findings. In 16 patients with asynergy restricted to the inferior and/or posterolateral segment, surface potential abnormalities due to infarction were observed during specific phases of QRS and in specific portions on the chest surface depending on the location and extent of ventricular severe asynergy (akinesis and dyskinesis). However, the remaining eight patients with coexisting severe asynergy in the anterior, apical, or septal segment showed surface potential maps quite different from those of the former patients. It is suggested that body surface isopotential maps are a useful clinical tool for detecting the location and extent of ventricular severe asynergy in patients with old inferoposterior myocardial infarction.

BODY SURFACE ISOPOTENTIAL MAPS OF EXPERIMENTALLY INDUCED TRANSIENT RIGHT BUNDLE BRANCH BLOCK

The characteristic patterns of the epicardial activation and body surface isopotential maps (MAPs) were examined in experimental transient right bundle branch block (RBBB) produced by pressing the main stem of right bundle mechanically. During the recovery from the complete block, various degrees of incomplete RBBB (IRBBB) were obtained. The epicardial activation of IRBBB spread in almost normal fashion with delayed right ventricular epicardial breakthrough. And the MAPs manifested intermediate patterns between those obtained in control and in complete RBBB (CRBBB). The MAP patterns of IRBBB were classified into the following 3 groups by the difference of the localized bend of isopotential lines reflecting the epicardial breakthrough. In the advanced IRBBB with QRS prolongation over 25%, the epicardial breakthrough of the left ventricle was detected on the MAPs. In the moderate IRBBB with QRS prolongation around 20%, in addition to the left ventricular breakthrough the right ventricular breakthrough was detected at the center of the anterior chest. In the mild IRBBB with QRS prolongation less than 15%, only the right ventricular breakthrough was detected. These findings indicate usefulness of MAPs for diagnosing the severity of IRBBB due to the damage to the main right bundle. Moreover, these MAP patterns in IRBBB of main right bundle can be distinctly differentiated from the IRBBB MAPs resulting from incisional interruption of lateral branches of right bundle. The present findings also suggest the usefulness of MAPs in diagnosing the site of the conduction disturbance resulting in IRBBB.