Experimental Biology 2010: A Reduction In Ejection Fraction During Stress Within The Normal Range With Gated Spect Imaging Is Not Associated With Increased Mortality

Purpose of Study: We sought to establish the prognostic significance of a stress induced fall in ejection fraction =10 in patients with normal resting baseline systolic function whose ejection fraction(EF) falls with stress but remains within the normal range.

Methods Used: 5,600 patients underwent gated, nuclear myocardial SPECT stress testing over a period of 6 years. Patients were followed prospectively and mortality assessed from the centralized Veterans Affairs electronic medical record (CPRS-VISTA). All cause mortality was compared between patients with normal systolic function where a post stress EF remained unchanged and those patients whose post stress EF remained within the normal range but decreased by =10

Summary of Results: A total of 1441 patients had a normal resting systolic function that remained unchanged with stress while 139 patients demonstrated a stress induced fall in EF =10 while still remaining within the normal range (>=46%). Both groups were similar with respect to age (63±14; 65±12 yrs), weight (197±46;199±52 lbs), and resting blood pressure (128±20; 128±20 mmHg; p=ns). Resting EF was significantly higher (59±8%; 68±7%; p<0.05) in those pts where stress induced EF fall of =10 while still remaining in the normal range. During a follow up period of 6 yrs survival was 94% at 1 yr, 85% at 3 yrs, & 78% at 5 yrs with no differences between the two groups.

Conclusions: In patients with normal resting systolic function a stress induced fall in EF =10 when remaining within the normal range does not have an adverse effect on survival.