Ejection fraction (EF) reflects both cardiac function and remodeling, and is widely recognized as a valuable diagnostic and prognostic tool. Its use in a variety of settings, ranging from heart failure and myocardial infarction to valvular heart disease, has made it a cornerstone of modern cardiology, pervading guidelines and practice. However, the development of the test was in another era, with younger patients and a lower prevalence of heart failure with preserved EF. The performance expectations of EF in the current era are also demanding—in relation to detection of subclinical LV dysfunction, and especially relating to recognition of changes in LV function on sequential testing—for example in patients taking cardiotoxic drugs. This review discusses whether the impressive evidence base for EF justifies its ongoing use in the context of newer markers of LV function, and the sophisticated questions posed by modern cardiology.
Before the development of left ventricular (LV) imaging, the assessment of cardiac function was limited to the measurement of pressure and flow. The development of left ventriculography and indicator dilution techniques in the early 1960s enabled estimation of LV volumes, and ejection fraction (EF) as stroke volume indexed to end-diastolic volume . The resulting measurement of cardiac function is now a keystone of modern cardiology, pervading guidelines and practice. This review discusses whether this evidence base justifies its ongoing use in the context of newer markers of LV function, and the more sophisticated questions posed by modern cardiology.
Proposed Decision Process About When to Trust and Distrust Ejection Fraction
Explanation GLS see link below to my Drive
There is broad value in gathering global longitudinal strain (GLS) in every case, but the enclosed scenarios summarize where this measurement is most useful. 3D = 3-dimensional; EF = ejection fraction; HF = heart failure; ICD = implantable cardioverter-defibrillator; LV = left ventricular; MI = myocardial infarction.
Assessment of the Athlete’s Heart
This athlete showed severe LV enlargement with mild dysfunction on the basis of 2DE (LV end-diastolic 143 ml/m2, LV end-systolic 77 ml/m2, stroke volume 119 ml, EF 0.46) and 3DE (LV end-diastolic 136 ml/m2, LV end-systolic 70 ml/m2, stroke volume 118 ml, EF 0.48) (A). Stroke volume is validated with pulsed-wave Doppler (117 ml) (A). Medial and lateral tissue velocity (mean 12 cm/s) and global longitudinal strain (19%) are consistent with normal myocardial function (B). 2DE = 2-dimensional echocardiography; 3DE = 3-dimensional echocardiography; EF = ejection fraction; LV = left ventricular.
This asymptomatic, but inactive, elderly patient with type 2 diabetes mellitus (T2DM) shows normal LV size and ejection fraction (0.59%), but impaired GLS (15%) (A). The presence of myocardial disease is supported by LA enlargement (38 ml/m2), and mild concentric remodeling (LV mass 121 g, relative wall thickness 0.44), despite normal diastolic function and tissue Doppler (B). This pattern of impaired GLS without diastolic dysfunction accounts for a subgroup of T2DM patients with LV dysfunction LA = left atrial;
The time to peak LV deformation in all myocardial segments provides a measure of contractile dispersion. This is predictive of arrhythmias. Reproduced with permission from Haugaa et al. ECG = electrocardiogram; ICD = implantable cardioverter-defibrillator; SD = standard deviation;
There can be few parameters in the whole of medicine that have had such a ubiquitous role in the characterization and management of disease as EF in cardiology. Despite its limitations, it is hard to anticipate a situation in which EF would no longer be used for the detection of LV systolic dysfunction and the consequent prognostic implications of this condition. Advances are continuing in the main alternative methodologies; new CMR protocols are shorter, potentially reducing cost, whereas improvements in 3DE have enabled many echo acquisitions to be performed using a single beat, thereby removing the need for breath-holding and potential stitch artifacts. Moreover, in the age of machine learning, automation is already being seen in the process of tracing the endocardium. Nonetheless, caution is necessary concerning the use of semiautomatic algorithms to calculate volumes and EF, regardless whether from 2D or 3D data. Manual correction is important, although it has been made difficult by the presentation of only thumb-sized LV images with most software. Other improvements can be expected that might ensure that appropriate 2D image planes are selected, or cross-correlation with other measurements (e.g., Doppler).
Nonetheless, disease phenotypes have changed from the era when EF was developed, and we now have an expectation of identifying disease at an early stage. In many situations, the information provided by EF is inadequate; this is especially the case in the assessment of HFpEF and the recognition of SBHF, but is also pertinent to amyloidosis, hypertrophic cardiomyopathy, and the recognition of LV impairment in various valvular heart diseases, including regurgitant lesions and AS. There is a risk that classification by EF will be a barrier to deeper phenotyping of these illnesses—which is essential to develop targeted treatment strategies. Thus, the best way forward seems to be to retain EF because of its historical role and evidence base, but to accept that in a number of circumstances, EF alone is insufficient (
Central Illustration). New and more sensitive markers of LV dysfunction, especially GLS, should be used when EF appears to be normal, or when particular diagnoses are sought where EF is unsuitable.
Further data in
JAMA Cardiology, published online February 27, 2019, regarding GLS and certain patterns correlate with specific disease processes. Global longitudinal strain provides potentially incremental information at all stages of HF and across the realms of prognostic evaluation, diagnosis, management guidance, and follow-up. Multicenter studies using GLS are in progress, but especially in relation to HFpEF, the adoption of GLS in clinical trials has been slow.
