Assessment by Radionuclide Cineangiography

We determined the sequence and timing of inward ventricular wall motion by least-square phase analysis of radionuclide cineangiograms in 10 patients with left bundle branch block (LBBB), five patients with right bundle branch block (RBBB) and 11 patients with normal conduction. All LBBB and RBBB patients had normal coronary arteries and no segmental wall motion abnormalities. The left ventricle (LV) was divided into eight segments and the right ventricle (RV) into three; sequence and timing were scored by three observers. In normal subjects, wall motion begins in either or both ventricles and ends in the LVor both ventricles. In patients with LBBB it begins in the RVand ends in the LV; in patients with RBBB is begins in the LV and ends in the RVor both ventricles. The intraventricular wall motion is also altered in the ventricle ipsilateral to a bundle branch block. In LBBB, the mean time of onset of LV wall motion is delayed 1.9 frames (38 msec), whereas RV wall motion is normal. In RBBB, the onset ofRV wall motion is delayed 1.3 frames (26 msec), whereas LV wall motion is not delayed. The sequence and timing of ventricular wall motion in normal conduction and bundle branch block, as represented by least-square phase analysis of radionuclide cineangiograms, conform with previous angiographic and electrophysiologic studies. Thus, this method may be useful in analyzing other conditions characterized by abnormal ventricular activation.