What is the difference between Early Diastolic Pulmonary Systolic (EPSS) and Velocity Time Integral (VTI) in Point of Care Ultrasound (POCUS)?

From the Guidelines

When comparing EPSS and VTI in point-of-care ultrasound (POCUS), EPSS is generally preferred for rapid assessment of left ventricular function while VTI is better for quantitative cardiac output measurement. The difference between Early Diastolic Pulmonary Systolic (EPSS) and Velocity Time Integral (VTI) lies in their measurement techniques and the information they provide about cardiac function. EPSS measures the minimum distance between the anterior mitral valve leaflet and the interventricular septum during early diastole, with values >7mm suggesting reduced ejection fraction 1.

Key Differences

• EPSS is relatively easy to obtain, even for novice sonographers, and requires only a parasternal long axis view.
• VTI, measured in the left ventricular outflow tract using pulsed wave Doppler, provides a more precise assessment of stroke volume and cardiac output when multiplied by the LVOT area.
• VTI requires more technical skill, additional views, and more time to perform accurately.

Clinical Application

For emergency or critical care settings where rapid assessment is needed, EPSS offers a quick screening tool for systolic dysfunction, while VTI should be used when more detailed hemodynamic information is required, particularly when monitoring response to interventions 1. Both measurements complement each other, with EPSS providing qualitative assessment and VTI offering quantitative data about cardiac function.

Recommendations

• Use EPSS for initial rapid assessment of left ventricular function in critical care settings.
• Use VTI for more precise measurement of cardiac output when detailed hemodynamic information is necessary.
• Consider the technical skill and time required for each measurement when deciding between EPSS and VTI in point-of-care ultrasound.

From the Research

Difference between EPSS and VTI in POCUS

• EPSS (E-Point Septal Separation) is a measure used to evaluate systolic function in echocardiography, as seen in studies 2, 3.
• VTI (Velocity Time Integral) is not explicitly mentioned in the provided studies, however, it is a measure used to calculate cardiac output, which is related to the evaluation of cardiac function.
• EPSS is used to diagnose reduced Left Ventricle Ejection Fraction (LVEF) in emergency department patients, with a cut off point at 9.5 mm having good sensitivity, specificity, and likelihood ratios 2.
• Cardiac point-of-care ultrasound (POCUS) can be used to evaluate various aspects of cardiac function, including left ventricular systolic and diastolic dysfunction, pericardial effusion and tamponade, and valvular dysfunction 4.
• POCUS can also be used to guide resuscitation in the prehospital setting and during critical care transport, as highlighted in a case study 3.

Measurement and Evaluation

• EPSS is measured through point-of-care ultrasound (POCUS) and has been shown to be a reliable method for diagnosing reduced LVEF in patients with cardiovascular symptoms 2.
• The use of POCUS to measure cardiac output and evaluate cardiac function is a valuable tool in the emergency department and intensive care unit, particularly in patients with cardiogenic shock 5.
• POCUS can provide a quick and accurate assessment of a patient's cardiovascular and hemodynamic status, allowing for timely management and intervention 3, 6.