First phase ejection fraction in aortic stenosis; a useful new measure
of early left ventricular systolic dysfunction
Abstract
In aortic stenosis (AS), a left ventricular (LV) ejection fraction (EF)
<50% or symptoms are class I indications for aortic valve
intervention. However, an EF <50% may be too conservative
since subendocardial fibrosis may already have developed. An earlier
marker of LV systolic dysfunction is therefore needed and first phase EF
(EF1) is a promising new candidate. It is the EF measured over early
systole to the point of maximum transaortic blood flow. It may be low in
the presence of preserved total LV EF since the heart may compensate by
recruiting myosin motors in later systole. The EF1 is inversely related
to the grade of AS and directly related to markers of subendocardial
fibrosis like late gadolinium enhancement on cardiac magnetic resonance
scanning. A reduced EF1 (<25%) predicts adverse clinical
events better that total EF and global longitudinal strain. We suggest
that it is worth exploring as an indication for surgery in patients with
asymptomatic severe AS.