Assessment of Left Ventricular Systolic Function with POCUS
A Guide for Non-Cardiologists - Part 3
Left ventricular (LV) dysfunction is a cross-sectional finding in multiple medical emergencies as a cause or complication of acute illness. Assessing LV function has been shown to increase accuracy in diagnosis and improve prognosis by changing the immediate management of different acute care scenarios.?
On the other hand, the incidence of acute decompensated heart failure (ADHF) among inpatients is substantial and clinicians may fail to recognize mild clinical signs. The non-diagnostic of ADHF is associated with increased morbidity, mortality, and length of stay, the assessment of LV systolic function by bedside ultrasound is a rapid and accurate way of diagnosis.?
This is more than a LinkedIn article! Authored by Núria Jorge, it is a mini-review that aims to improve the expertise in POCUS assessment of LV systolic function, by combining qualitative and semi-quantitative methods and propose a standardized POCUS assessment of LV systolic function.
With the valuable contribution of Martim Trov?o Bastos, Rui Carvalho, Fábio Barbosa, Beatriz R. Sousa, Nuno Amorim, Antony Soares Dionísio, Dolores Vázquez, Sheila Arroja, @José Mariz, this three-part series provides a comprehensive guide for non-cardiologist physicians to accurately and swiftly evaluate LVSF using POCUS.
This sequence provides a comprehensive understanding of LVSF assessment, from basics to advanced concepts and practical applications.
If you haven't already, review Parts 1 and 2 of this series for foundational concepts, before continuing with this guide for non-cardiologist physicians to accurately and swiftly evaluate LVSF using POCUS.
Part 1 - Focuses on qualitative LVSF assessment ("eyeballing" the heart using visual cues and ultrasound images).
Part 2 - Explores the semi-quantitative methods, providing objective measurements to complement the qualitative assessment.
The Importance of Accurate LVEF Measurement
LV systolic function is generally assessed by measuring the LV ejection fraction (LVEF), corresponding to the percentage of blood pumped out of the LV each cardiac cycle (LVEF = stroke volume / end-diastolic volume).?
Accurate measurement of LVEF is one of the cornerstones of formal echocardiography. LVEF categorization varies between different international societies.?
In addition, even if all these conditions are present, LVEF measurement can lead to an incomplete or incorrect estimation of LV function. This is seen in the presence of geometric confounders (hypertrophic cardiomyopathy or small cavity size ventricles), alterations in LV load (such as shock or valvular heart disease), or cases of arrhythmic events.?
All these alterations can be seen in acute illness, rendering Modified Simpson's method impractical in point-of-care ultrasound (POCUS) assessment.?
The Role of POCUS in LV Systolic Function
POCUS echocardiography is performed at the bedside not only by cardiologists but also by general or emergency physicians to answer focused clinical questions, narrow the differential diagnosis, and guide adequate treatment. This tool is now essential for hemodynamic assessment and has become widespread in clinical practice.?
POCUS qualitative evaluation of the LV systolic function is described in numerous studies as accurate and effectively performed by physicians with brief formal training. In the last decades, other simpler quantitative methods have been developed for LVEF assessment in the emergency field, which is believed to be performed by this bedside assessment.?
Training Requirements and Learning Curve: The Foundation of Effective Cardiac POCUS
Nowadays cardiac ultrasound evaluation is routinely performed by non-cardiologists in intensive care units (UCI), emergency departments, wards, and even in the pre-hospital setting. The present approach aims to make LV function assessment easier and more practical, but consideration must be given to its pivotal points and potential limitations.?
The first step to an adequate POCUS evaluation is good image acquisition and, although many studies advocate a rapid learning curve, the image acquisition skill requires at least three months of training.
The systematic review and meta-analysis by Jenkins S et al., Diagnostic accuracy of handheld cardiac ultrasound device for assessment of left ventricular structure and function: systematic review and meta-analysis, showed that a scan performed by an experienced operator had three to six times higher odds of detecting LV dysfunction, dilation or wall motion abnormalities, than if performed by an inexperienced one.
This highlights the importance of adequate training and supervision for better diagnostic capacity and clinical management.?
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Qualitative and Quantitative Assessments
POCUS assessment aims to answer time-sensitive clinical questions in emergency settings. The ability to qualitatively characterize the LV function as normal, reduced, or hyperdynamic, has more immediate clinical impact than a precise measure of the ejection fraction when done consistently.?
Nevertheless, a sole qualitative assessment may hinder peer-to-peer discussion and monitoring of the clinical course, as the medical community craves more objective values.?
On the other hand, quantifying LVEF is often time-consuming and technically challenging, as was shown in this study by Moore et al., Determination of left ventricular function by emergency physician echocardiography of hypotensive patients, in which emergency physicians took an average of 17 minutes to evaluate LVEF in hypotensive patients.?
The Role of M-Mode Techniques in LV Function Assessment
Alternative measures such as the E-point septal separation, fractional shortening, and mitral annular plane systolic excursion have earned their place in this type of assessment.
As M-Mode dependent techniques they are quicker and easier to perform. Although very useful in evaluating a LV geometrically normal, the M-mode assessment is not as reliable in the presence of structural variations, like in dilated or asymmetrical ventricles.?
Interventricular septum motion changes stand out as another limitation of this screening method, an easily seen alteration in cases of complete left bundle branch block, pacemaker wearers, or right ventricular volume overload. Thus, despite the use of recommended semi-quantitative methods, these clinical and morphological entities should not be overlooked.?
Cardiac Evaluation by POCUS
Guidelines developed by American and European societies for bedside ultrasound evaluation in emergency medicine and intensive medical care do not reduce the cardiac assessment to the definition of LV function. Other factors like cardiac chamber dimensions, volume status, valvular abnormalities, or pericardial effusion should be considered in POCUS evaluation.?
Nevertheless, LV function is one of the most important data to be withdrawn in the cardiac evaluation by POCUS, as it is essential to hemodynamic assessment in acute care scenarios.?
The qualitative and semi-quantitative approaches described don’t necessarily have to be all done when assessing this data and the time is not always enough to do it so thoroughly. The “eyeballing” is still a proven option for LV function characterization, once POCUS is frequently performed in symptomatic patients whose pathologic findings may be more pronounced.?
Advancements in POCUS Technology
Lastly, consideration must be given to technological evolution. Multiple hand-held ultrasound devices have been developed and approved for clinical use. Although most of them have B-mode, M-mode, and Doppler, they have different characteristics in image acquisition and capabilities.?
On the other hand, LVEF automatic measurement software, which uses endocardium tracing, is being developed, and despite its limitations still being discussed, it has the potential to become a transversal tool for LV function assessment in the future.
This article does not explore the evaluation of LV systolic function for different hand-held devices or LVEF measurement by semiautomatic software.
Knowing the qualitative and semi-quantitative assessment methods, the technique behind them, and their limitations, allows the POCUS approach described to be carried out by non-cardiologist physicians in just four cardiac views and LV function measured rapidly, accurately, and consistently at the bedside.
A Guide for Non-Cardiologists
The assessment of LV systolic function provides important information to guide management in acutely ill patients. Its evaluation should be accurately and quickly done at the bedside, a goal that can be challenging.?
This review proposes a POCUS approach designed to integrate different qualitative and semi-quantitative measurements of LV systolic function, to improve the proficiency in cardiac assessment by non-cardiologist physicians in emergency settings.
By integrating qualitative ("eyeballing") and semi-quantitative techniques, healthcare providers can confidently assess cardiac function and make informed decisions at the bedside.
Part 1 - Focuses on qualitative LVSF assessment ("eyeballing" the heart using visual cues and ultrasound images).
Part 2 - Introduces semi-quantitative methods, providing objective measurements to complement the qualitative assessment.
Part 3 - Explores the clinical applications and implications of these techniques for diagnosing and managing patients.
This three-part series provides a comprehensive guide for non-cardiologist physicians to accurately and swiftly evaluate LVSF using POCUS.
Review all three parts of this series to enhance your POCUS skills and optimize patient care, and don't forget to share this valuable content with your colleagues!