Ejection fraction by radionuclide ventriculography and contrast left ventriculogram - A tale of two techniques

Objectives. We assessed the abilities of two methods to measure ejection fr action (EF)-radionuclide ventriculography (RVG) and contrast left ventricul ography (Cath-EFa) to predict cardiovascular events. Background. Both RVG and Cath-EFa are commonly used methods to measure left ventricular performance and assess prognosis. Their comparative abilities to predict clinical events have not been reported. Methods. Both RVG EF and Cath-EFa were measured within 16 days of myocardia l infarction (MI) in 688 patients. The results were divided into terciles, Prognosis by terciles was assessed for each technique. A multivariate analy sis was performed to determine which EF measurement was a better predictor of prognosis. Results, Average RVG-EF was 32% +/- 7, while Cath-EFa was 42% +/- 10. Both RVG and Cath-EFa were poorly correlated (R = 0.42), Event rate declined acr oss terciles with increasing EF for both techniques (events in lowest to hi ghest tercile of Cath-EFa 40.7%, 25.9%, 11.6%, p < 0.001; and RVG-EF 39.9%, 26.1%, 15.6%, p < 0.001), There was concordance of terciles in 303 of 688 patients (44%), When patients in the highest RVG terciles were in the highe st Cath-EFa tercile, the event rate was 7%, However, when patients in the h ighest RVG terciles were in the lowest Cath-EFa tercile, the event rate was 19%. Both Cath-EFa (p < 0.001) and RVG-EF (p < 0.001) were independent pre dictors of cardiovascular events. Conclusions. Ejection fraction measured by RVG or during catheterization is a valuable tool in the risk stratification of postinfarct patients. When d isagreement is present between clinical impression and measurement by eithe r method, the use of an alternative measurement is warranted and complement ary. (C) 1998 by the American College of Cardiology.