RESUMO
BACKGROUND: To detect ischemia in patients with angina and normal coronaries frequently represents a complex diagnosis. METHODS: To investigate whether left ventricular mechanical dyssynchrony by phase analysis contributes in the evaluation of patients with chest pain and normal coronaries, gated-SPECT myocardial perfusion imaging (MPI) at rest and 30 minutes post-stress was performed in 218 patients with normal epicardial coronaries, who were divided into two groups: those with summed difference score (SDS) ≥ 4 (54 patients, Group 1), and those with SDS < 4 (164 patients, Group 2). Intraventricular synchronism-phase standard deviation (PSD) and histogram bandwidth (HBW)-was evaluated by phase analysis. RESULTS: Women were significantly more frequent in Group 2 (those without ischemia in SPECT MPI): 113 (69%) vs 25 (46%), P = .00001. In males, left ventricular ejection fraction (LVEF) and ventricular volumes were not significantly different between patients with or without ischemia. However, ischemic females showed significantly higher ventricular volumes, minor post-stress LVEF and more negative delta LVEF (- 3.9 vs 0.34, P = .0008) than the non-ischemic ones. There was a significant post-stress increase of PSD and HBW among males, although not among females. According to SSS (≥ 4, with ischemia/necrosis; < 4, without ischemia/necrosis), post-stress PSD and HBW significantly increase both in male and female, and PSD and HBW were significantly higher in females with SSS ≥ 4 compared to those with SSS < 4 (PSD rest: 19.04° vs 11.72°, P < .0001; HBW rest: 58.85° vs 38.21°, P < .0001). PSD and HBW were also higher among males with SSS ≥ 4 compared to those with SSS < 4, although not significantly. CONCLUSION: Higher ventricular volumes in females and dyssynchrony are associated with inducible ischemia in MPI in patients with chest pain and normal coronaries. Stress-induced ischemia increases degree of dyssynchrony.