Relation between mean ventricular phases in chronic cor pulmonale measured by radionuclide ventriculography.

ECG-gated equilibrium radionuclide ventriculography was performed in 17 patients with pulmonary heart disease (Cp) and in 11 healthy subjects (Nm). Fourier analysis was applied to the time activity curve in each pixel, and the phase and amplitude of the basic frequency were computed. From the pixel-by-pixel values, the mean phase of each ventricle was calculated. It was found that the difference between mean phase of right and left ventricle (psi(R-L)] was significantly greater in Cp (+13.8 degrees +/- 7.8 degrees) than in Nm (-0.3 degrees +/- 3.9 degrees). This difference was almost twice as great in Cp with RV failure (+15.9 degrees +/- 7.8 degrees) than in those without it (+8.8 degrees +/- 5.1 degrees). Abnormally increased psi(R-L) values were detected in about 70% of patients with Cp. Interventricular phase difference had a weak positive correlation with the amplitude of S wave in lead I of the ECG (r = 0.533). It is concluded that in most patients with Cp the phase of the RV contraction is delayed and that this delay may be connected with deterioration of RV performance.