[Clinical Study of Phase Analysis by RI Multigated Method]

Phase analysis using RI multigated method was performed in 32 patients with various conditions including right and left bundle branch blocks (RBBB and LBBB), myocardial infarction, WPW syndrome, QT prolongation syndrome, atrioventricular (A-V) dissociation, valvular heart disease, and others. Pixel numbers were plotted into the histogram regarding the one cardiac cycle as 360 degrees. Standard deviation (S.D.) of a phase was calculated from the histogram in order to quantify asynchrony of the ventricles. Results were as follows: 1. Phase analysis was useful as a parameter of asynchrony. 2. There was a close negative correlation between left ventricular ejection fraction (LVEF) and S.D. of a phase. (r = -0.86, n = 32, p less than 0.001) 3. A marked time lag was observed in the infarcted area, and its value was mild in RBBB and LBBB. 4. A time lag between right and left ventricles was diminished or slightly reversed in the cases of RBBB with left anterior hemiblock compared to the cases of lone RBBB. 5. No significant changes were observed in other heart diseases with phase analysis.