RESUMO
BACKGROUNDS: Left ventricular (LV) dyssynchrony reduces LV systolic function in patients with heart failure (HF). However, it remains unknown whether this relationship is independent of impaired LV myocardial perfusion. METHODS AND RESULTS: A total of 105 patients with chronic HF (age 71 ± 13 years; 71 men) were enrolled in the present study. (99m)Tc-sestamibi (MIBI) gated myocardial scintigraphy was performed at rest to assess LV myocardial perfusion as evaluated by the total defect score of perfusion Single Photon Emission Computed Tomography images (TDS-MIBI), LV systolic function as evaluated by LV ejection fraction (LVEF), and LV systolic dyssynchrony as evaluated by the maximal difference of time to end systole (MD-TES), which is the time lag between the earliest and the latest end systole among 17 LV segments analyzed with a novel program, "cardioGRAF". The mean ± SD (minimum and maximum range) of the MD-TES was 147.8 ± 117.5 (14.0-458.3)ms. The MD-TES was significantly higher in patients with LVEF<45% (199.4 ± 117.6 ms) than in those with LVEF ≥ 45% (60.5 ± 41.2 ms, p<0.001). In a multiple logistic regression analysis, the MD-TES showed an increased odds ratio for LVEF<45% (2.46 [95% CI; 1.51-4.01] per increment in decile of MD-TES rank, p<0.001), after adjusting for the TDS-MIBI, history of myocardial infarction, and other potential confounders. CONCLUSIONS: LV dyssynchrony is a significant determinant of LV systolic dysfunction in patients with HF, and this relationship is independent of impaired LV myocardial perfusion and history of myocardial infarction.