Abstract
To detect the site of origin of premature ventricular contractions (PVCs), echocardiography were recorded in forty-two patients with frequent PVCs but without organic heart disease. In All patients, wall motion during PVC were evaluated. In ten of these patients, the time intervals f romonset of QRS complex of PVC to beginning of contraction on M-mode echocardiography were measured. PVCs were classified into left bundle branch block (LBBB) type, right bundle branch block (RBBB) type and unclassified type, according to electrocardiographic patterns. Each type was subdivided into inferior and leftward axis subtypes. M-mode echocardiography showed abnormal early contractions and late abnormal wall motions during PVC. Abnormal wall motions at PVC were recognized on anterior wall of the right ventricle (RV), interventricular septum (IVS) and lateral wall of left ventricle (LV) in type of LBBB with inferior axis; on posterior wall of RV and IVS in type of LBBB with leftward axis; on posterior wall and lateral wall of LV and anterior IVS in type RBBB with inferior axis; on inferior wall of LV and IVS in type of RBBB with leftward axis; on anterior IVS lateral wall and posterior wall of LV in type of unclassified pattern with inferior axis; on posterior wall of RV, inferior wall of LV and IVS in type of unclassified pattern with leftward axis respectively. National Sanatorium Kanagawa Hospital When the time intervals from onset of QRS complex to beginning of contraction were measured during PVC, the site of earlist contraction was near the anterior IVS in type of LBBB with inferior axis; near the inferior IVS in type LBBB with leftward axis; from the anterior IVS to lateral wall of LV in type of RBBB with inferior axis; near the inferior IVS in type of RBBB with leftward axis; near the anterior IVS in type of unclassified pattern with inferior axis; and near the inferior IVS in type of unclassified pattern with leftward axis, it seems to be usefull to estimate the origin of PVC by echocardiography.
