From the Guidelines
The most important measures of left ventricular (LV) systolic function on transthoracic echocardiography (TTE) are left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS), with LVEF being the primary measure, as evidenced by the most recent study 1. When evaluating LV systolic function, it is essential to consider multiple parameters to get a comprehensive understanding of the patient's condition.
- LVEF is calculated as the percentage of blood ejected from the LV during systole, with normal values typically above 55% 1.
- GLS is a more sensitive measure that detects early systolic dysfunction before LVEF declines, with normal values around -18% to -22% (more negative values indicating better function) 1.
- Regional wall motion assessment evaluates the contractility of individual LV segments, graded as normal, hypokinetic, akinetic, or dyskinetic.
- Additional supportive measures include fractional shortening, stroke volume, cardiac output, and tissue Doppler imaging of the mitral annulus (S') 1. These parameters should be interpreted together rather than in isolation, as each has limitations. Technical factors such as image quality, proper alignment, and accurate border tracing significantly impact measurement accuracy, and values should always be considered in the clinical context of the patient 1. In clinical practice, the choice of parameters may vary depending on the specific patient population and the availability of resources, but LVEF and GLS are the most critical measures of LV systolic function, as supported by the latest evidence 1.
From the Research
Measures of Left Ventricular Systolic Function
The following are important measures of left ventricular (LV) systolic function on transthoracic echocardiogram (TTE):
- Left ventricular ejection fraction (LVEF) [ 2, 3, 4, 5, 6 ]
- Global longitudinal strain (GLS) from speckle tracking echocardiography (STE) [ 3, 5, 6 ]
- Left ventricular relative wall thickness (RWT) [ 2 ]
- Left ventricular ejection time (LVET) [ 2 ]
- Mitral annular plane systolic excursion [ 4 ]
- Mitral annular velocity derived from tissue Doppler [ 4 ]
- Systolic time intervals [ 4 ]
- Mitral regurgitation-derived LV dP/dt [ 4 ]
- Estimation of cardiac output by Doppler echocardiography [ 4 ]
- Myocardial work [ 5 ]
- LV torsion [ 6 ]
Advantages and Limitations of Each Measure
Each of these measures has its own advantages and limitations, including:
- LVEF: commonly used, but has limitations in terms of reproducibility and detection of LV dysfunction in pathologically remodeled hearts [ 3 ]
- GLS: sensitive and feasible method that overcomes many of the limitations of LVEF [ 3 ]
- RWT: easily derived measure of LV geometry on TTE, may identify clinically relevant subclinical systolic dysfunction and patients with worse kidney function [ 2 ]
- LVET: surrogate of subclinical systolic dysfunction [ 2 ]
- STE: allows assessment of LV function through measurement of myocardial strain, with a high temporal and spatial resolution and a better inter- and intra-observer reproducibility [ 6 ]