Fourier analysis in patients with different pacing modes

The purpose of this study was to evaluate the usefulness of phase analysis in detecting the altered activation sequence induced by different pacing modes. Radionulide ventriculography and planar gated blood pool scintigraphy were performed at rest in 56 patients with different pacemakers. This method permitted us to localize the pacemaker impulse site in the right ventricie and its diffusion in the heart. In patients with VVI pacemaker, this technique showed an evident asynchronism of contraction and relaxation of each ventricle and the standard deviation of phase angle (σ), calculated by computer, is greater during pacing than sinus rhythm for left (LV) and right (RV) ventricles (LV σ: 17°± 4 vs 11°± 3, < 0.001; RV σ: 31°± 7 vs 14°± 4, P < 0.001). In the patients with VVI rate responsive pacemakers, the LV σ changed from 18.5 ± 3 under pacing to 11°± 3 in sinus rhythm, P < 0.001, while the RV σ changed from 30°± 8 to 14°± 4, P < 0.001. Instead in the patients with DDD pacemakers, the LV σ changed from 15.5°± 2 under pacing to 11°± 3 in sinus rhythm, P < 0.05, while the RV cr changed from 29.1°± 6 to 14°± 4, P < 0.001. Besides in patients with VDD pacemakers, the LV σ changed from 14.9°± 3 during pacing to 11°± 3 in sinus rhythm, P < 0.01, and from 27.5°± 5 to 14°± 4 for the right ventricle, P < 0.01. So the technique of Fourier analysis permits us to examine the effects of a temporal inhomogeneity induced by different pacing modes, and it can be utilized to assess the optimal atrioventricular delay in DDD paced patients.