What are the steps to assess cardiac function with Transthoracic Echocardiography (TTE) based on American Society of Echocardiography (ASE) guidelines?

From the Guidelines

To assess cardiac function with transthoracic echocardiography (TTE) based on ASE guidelines, a comprehensive approach is necessary, incorporating the latest recommendations from high-quality studies, such as 1, which provides detailed guidance on the assessment of valvular heart disease.

Steps for Assessment

• Obtain standard imaging views including parasternal long-axis, parasternal short-axis, apical four-chamber, apical two-chamber, apical three-chamber, and subcostal views, as suggested by 1.
• Begin with 2D imaging to evaluate cardiac structure, chamber size, wall thickness, and qualitative function.
• Use M-mode for precise timing of cardiac events and measurement of chamber dimensions.
• Apply color Doppler to assess blood flow direction and identify regurgitation or stenosis.
• Use spectral Doppler (both pulsed-wave and continuous-wave) to measure blood flow velocities across valves and calculate pressure gradients, taking into consideration the guidelines for assessing valvular heart disease provided in 1.
• Tissue Doppler imaging should be performed to evaluate myocardial velocities and assess diastolic function.
• Calculate left ventricular ejection fraction using the biplane Simpson's method from apical four-chamber and two-chamber views.
• Assess right ventricular function using multiple parameters including TAPSE, S', FAC, and 3D volumetric assessment when available.
• Evaluate all four cardiac valves for morphology and function, measuring relevant parameters for any abnormalities detected, as recommended in 1.
• Document findings systematically in a comprehensive report that includes all quantitative measurements with normal reference ranges.

Considerations for Specific Conditions

• For patients with aortic stenosis, consider the key measurements for clinical decision-making, including maximum aortic velocity, mean pressure gradient, and valve area, as outlined in 1.
• In cases of severe aortic stenosis with low ejection fraction, dobutamine stress echocardiography may be useful to distinguish between severe AS with LV systolic dysfunction and primary myocardial dysfunction with moderate AS, as discussed in 1.

Importance of Recent Guidelines

The approach to assessing cardiac function with TTE should be guided by the most recent and highest quality studies, such as those referenced here, to ensure that the assessment is comprehensive and aligned with current standards of practice, thereby optimizing patient outcomes in terms of morbidity, mortality, and quality of life.

From the Research

Steps to Assess Left Ventricular Systolic Function with TTE

• The American Society of Echocardiography (ASE) guidelines recommend transthoracic echocardiography (TTE) as the primary method for assessing cardiac function 2.
• The measurement of left ventricular ejection fraction (LVEF) is crucial in determining the treatment strategy and prognosis of patients 2.
• 3D echocardiography is recommended for volume and LVEF measurements due to its higher accuracy and reproducibility compared to 2D echocardiography 2.
• New echocardiographic techniques, such as global longitudinal strain measured by speckle tracking and myocardial work, allow for earlier detection of myocardial abnormalities and have greater sensitivity in detecting ischemia, fibrosis, and left ventricular systolic dyssynchrony 2.

Assessment of Right Ventricular Function with TTE

• TTE can be used to estimate the severity of right ventricular dysfunction, with moderate or severe dysfunction having good sensitivity and specificity for right ventricular ejection fraction (RVEF) ≤ 35% 3.
• The right ventricular index of myocardial performance (RIMP) and right ventricular systolic pressure (RVSP) can be used to assess right ventricular function, with RIMP > 0.70 and RVSP > 70 mmHg being specific for RVEF ≤ 35% 3.
• TTE can also be used to assess right ventricular function in patients with heart transplantation, with reference values for chamber size and function, including cardiac mechanics, being derived from healthy heart transplant patients 4.

Additional Considerations

• The assessment of left ventricular diastolic function should be oriented towards non-invasive estimation of left ventricular filling pressures, using measurements such as E/e' ratio, pulmonary flow atrial reverse velocity, systolic pulmonary arterial pressure, and left atrial volume index 5.
• Bedside echocardiography can be used to assess right heart function in critically ill patients, with attention to the right ventricle providing insight into RV function and guiding patient management 6.