How best to assess right ventricular function by echocardiography

Abstract

Right ventricular function is a crucial determinant of long-term outcomes of children with heart disease. Quantification of right ventricular systolic and diastolic performance by echocardiography is of paramount importance, given the prevalence of children with heart disease, particularly those with involvement of the right heart, such as single or systemic right ventricles, tetralogy of Fallot, and pulmonary arterial hypertension. Identification of poor right ventricular performance can provide an opportunity to intervene. In this review, we will go through the different systolic and diastolic indices, as well as their application in practice. Quantification of right ventricular function is possible and should be routinely performed using a combination of different measures, taking into account each disease state. Quantification is extremely useful for individual patient follow-up. Laboratories should continue to strive to optimise reproducibility through quality improvement and quality assurance efforts in addition to investing in technology and training for new, promising techniques, such as three-dimensional echocardiography.

Keywords: Echocardiography; diastolic function; right ventricle; right ventricular function; systolic function.

Figure 1

The fractional area change is obtained by tracing the right ventricular endocardial border at end diastole and end systole. The difference in the area at end diastole and end systole is divided by the area at end diastole. This is a reproducible measure of function that is not affected by pericardiotomy. Normal fractional area change is above 35%. In this example, the fractional area change is diminished (26%), indicating impaired right ventricular function.

Figure 2

Tricuspid annular plane systolic excursion can beobtained usin gtwo-dimensional imaging (a and b)or by placing the M-mode cursor atthe level of the tricuspid valve annulus (c). The electrocardiogram tracing can be used to determine the optimal frame to be measured. This measure reflects the longitudinal shortening of the right ventricle. In adults, normal values are greater than 1.6 centimetres. Normative data for age are available for children. Tricuspid annular plane systolic excursion is helpful for the assessment of right ventriuclar function in patients with pulmonary hypertension and those with unoperated hearts. Although reproducible, this measure correlates poorly with ejection fraction by magnetic resonance and shodul be used with caution in congenital heart defects involving the right ventricle, such as single and systemic right ventricles, and tetralogy of Fallot.

Figure 3

Pulsed tissue Doppler can be used to calculate the tissue Doppler velocities of the tricuspid annulus. The S’ wave represents the systolic velocity, which assesses the right ventricular longitudinal function. The e’ wave represents the tricuspid annular early diastolic velocity, whereas the a’ wave represents the annular velocity with atrial contraction. E’ and a’ velocities are used in the assessment of right ventricular diastolic function.

Figure 4

Speckle tracking technology allows for the assessment of strain and strain rate as measures of the longitudinal function of the right ventricle. Image optimisation is required to demonstrate the entire right ventricular cavity in the imaging sector. Strain is a negative value, with more negative values indicating better function. Decreased strain appears to precede overt declines in right ventricular ejection fraction. Normal value in adults is −26 ± 4%.

Figure 5

Colour tissue Doppler interrogation of the tricuspid valve annulus for measurement of the isovolumic acceleration. Isovolumic acceleration is calculated by dividing the peak velocity at isovolumic contraction by the time from the onset of the wave to its peak velocity, also measured by tissue Doppler interrogation at the tricuspid valve annulus. Normal values are >1.1 m/s².

Figure 6

Three-dimensional calculation of right ventricular volumes and ejection fraction. Three-dimensional image acquisition is performed from the apical four-chamber view in order to maximise visualisation of the right ventricle. Data sets are analysed offline using a dedicated software. Manual tracing of the endocardial border in three planes – sagittal, frontal, and coronal – is required for this calculation. The figure on the right depicts normal ejection fraction (61%).

Figure 7

Inferior caval vein collapse can be identified by simple two-dimensional observation or using M-mode. The figure shows M-mode interrogation of normal inferior caval vein collapse with respiration, suggesting normal right atrial pressure.