Characterization of right or left ventricular contraction heterogeneity using Fourier phase analysis. Application to a group of patients with severe ventricular arrhythmias.

The standard deviation of the first harmonic Fourier phase histogram is an indicator of the contraction heterogeneity of the heart ventricles. This approach has been applied to analyse tomographic blood pool (99mTc) examinations in a group of 32 patients with angiographically verified mainly right (RV) but also left (LV) kinetic disorders in relation to severe ventricular arrhythmias and suspicion of arrhythmogenic right ventricular dysplasia (ARVD). The reference group consisted of ten patients with low probability of cardiac kinetic abnormalities. Thick tomographic slices including both ventricles have been reconstructed in the horizontal long axis orientation from a series of 32 gated projections recorded over a 360 degrees rotation. Separately for each ventricle the Fourier phase histograms have been computed and characterized by their standard deviations (PSD). Normal values (mean +/- standard deviation, LV = 11 degrees +/- 5 degrees, RV = 12 degrees +/- 5 degrees) were significantly lower (P less than 0.01 and P less than 0.001) than those measured in abnormal cases (LV = 19 degrees +/- 10 degrees and RV = 31 degrees +/- 17 degrees). Detailed analysis of the data supports the hypothesis of a primary RV disease in ARVD, with secondary LV extension. PSD seems to be a good predictor of an organic cardiac disease underlying ventricular arrhythmias and may be used for screening the patients.