Age- and gender-specific differences in left ventricular cardiac function and volumes determined by gated SPET

The aim of this study was to determine normative volumetric data and ejecti on fraction values derived from gated myocardial single-photon emission tom ography (SPET) using the commercially available software algorithm QGS (qua ntitative gated SPET), From a prospective database of 876 consecutive patie nts who were referred for a 2-day stress-rest technetium-99m tetrofosmin (9 25 MBq) gated SPET study, 102 patients (43 men, 59 women) with a low (<10%) pre-test likelihood of coronary disease were included (mean age 57.6 years ). For stress imaging, a bicycle protocol was used in 79 of the patients an d a dipyridamole protocol in 23. Left ventricular ejection fraction (LVEF) and end-diastolic and -systolic volumes (EDV and ESV) were calculated by QG S. EDV and ESV were corrected for body surface area, indicated by EDVi and ESVi. To allow comparison with previous reports using other imaging modalit ies, men and women were divided into three age groups (<45 years, greater t han or equal to 45 years but <65 years and <greater than or equal to>65 yea rs). Men showed significantly higher EDVi and ESVi values throughout and lo wer LVEF values when compared with women in the subgroup greater than or eq ual to 65 years (P<0.05, ANOVA). Significant negative and positive correlat ions were found between age and EDVi and ESVi values for both women and men and between LVEF and age in women (Pearson P<less than or equal to>0.01). LVEF values at bicycle stress were significantly higher than at rest (P=0.0 00, paired t test), which was the result of a significant decrease in ESV ( P=0.003), a phenomenon which did not occur following dipyridamole stress (P =0.409). The data presented suggest that LVEF and EDVi and ESVi as assessed by QGS are strongly gender-specific. Although the physiological significan ce of these results is uncertain and needs further study, these findings de monstrate that the evaluation of cardiac function and volumes of patients b y means of QGS should consider age- and gender-matched normative values.