EVALUATION OF LEFT-VENTRICULAR ASYNCHRONY BY RADIONUCLIDE ANGIOGRAPHY- COMPARISON OF PHASE AND SECTOR ANALYSIS

The aim of this study was to assess the optimal method to evaluate asy nchrony in equilibrium radionuclide angiography (RNA). Methods: We stu died 20 patients (14 males and 6 females, age range 25-60 yr) with RNA during atrial and sequential atrioventricular (AV) pacing, which incr eased left ventricular (LV) asynchrony. Both studies were performed at the same heart rate. Asynchrony was assessed either on phase images, by computing the standard deviation of the phase distribution (SD-P) a nd by sector analysis. Systolic and diastolic asynchrony were evaluate d as the coefficient of variation of time to end systole (CV-TES) and time to peak filling rate (CV-TPFR) in four sectors. In addition, phas e values were computed on time-activity curves from the same sectors, and their standard deviation (SD-Psec) was computed. Results: During a trial pacing SD-P was 32.3 degrees +/- 6.7 degrees and did not change during AV pacing (32.1 degrees +/- 5.6 degrees, p = n.s.). Both CV-TES and CV-TPFR had a significant increase during AV pacing (from 7.7% +/ - 3.9% to 11.5% +/- 6.4%, p < 0.01, and from 8.4 degrees +/- 5.8 degre es to 12.9 degrees +/- 6.7 degrees, p < 0.001). AV pacing led to a sig nificant increase in SD-Psec (from 6.3 degrees +/- 4.0 degrees to 12.6 degrees +/- 9.7 degrees, p < 0.05). Moreover, reproducibility was ass essed in 15 additional age-matched patients. The results of the reprod ucibility study indicate a better repeatability for CV-TES and CV-TPFR . Conclusions: The findings of this study suggest that sector analysis with calculation of indices of LV systolic and diastolic asynchrony i s better suited for quantitation of LV temporal nonuniformity.