From the Guidelines
Right ventricular (RV) strain on echocardiography is identified through several key findings, including RV dilatation, RV hypokinesis, and a reduced tricuspid annular plane systolic excursion (TAPSE) <17mm, as outlined in the 2019 ESC guidelines 1.
Key Findings
- RV dilatation with a basal diameter >42mm or mid-cavity diameter >35mm
- RV hypokinesis
- Reduced tricuspid annular plane systolic excursion (TAPSE) <17mm
- Paradoxical septal motion (D-shaped left ventricle)
- Increased RV/LV ratio >0.9
- Elevated tricuspid regurgitation velocity >2.8 m/s
- Reduced RV fractional area change <35%
- Tissue Doppler may show reduced RV S' velocity <9.5 cm/s
Diagnostic Considerations
These echocardiographic parameters are crucial for diagnosis as RV dysfunction is often clinically silent until advanced stages. Early detection allows for prompt intervention, which may include anticoagulation for pulmonary embolism, pulmonary vasodilators for pulmonary hypertension, or appropriate heart failure management depending on the underlying cause. The 60/60 sign, McConnell sign, and right-heart thrombi are more specific echocardiographic findings that justify emergency reperfusion treatment for PE if immediate CT angiography is not feasible in a patient with high clinical probability and no other obvious causes for RV pressure overload 1.
Clinical Context
RV strain can result from conditions like pulmonary embolism, pulmonary hypertension, right-sided heart failure, or RV infarction. Mobile right-heart thrombi are detected by TTE or transoesophageal echocardiography (TOE), or by CT angiography, in <4% of unselected patients with PE, but their prevalence may reach 18% among PE patients in the intensive care setting 1.
Management
In a haemodynamically compromised patient with suspected PE, unequivocal signs of RV pressure overload, especially with more specific echocardiographic findings, justify emergency reperfusion treatment for PE if immediate CT angiography is not feasible in a patient with high clinical probability and no other obvious causes for RV pressure overload 1.
From the Research
Echocardiographic Findings of RV Strain
The following are echocardiographic findings that suggest right ventricular (RV) strain:
- Increased right ventricle: left ventricle size ratio 2
- Abnormal septal motion 2
- McConnell's sign 2, 3
- Tricuspid regurgitation 2
- Elevated pulmonary artery systolic pressure 2
- Decreased tricuspid annular plane systolic excursion 2, 4, 5
- Decreased S' 2
- Pulmonary artery mid-systolic notching 2
- 60/60 sign 2
- Speckle tracking demonstrating decreased right ventricular free wall strain 2, 6, 4, 3, 5
Measurement and Clinical Application of RV Strain
RV strain can be measured using speckle-tracking echocardiography, which has emerged as a reproducible and feasible technique for quantifying RV function 6. The clinical use of RV strain includes assessing RV function in patients with heart failure, ischemic heart disease, pulmonary hypertension, and other cardiovascular diseases 6. RV subcostal strain has been shown to be a reliable surrogate for conventionally derived strain in critical care 4.
Regional RV Strain Pattern in Patients with Acute Pulmonary Embolism
Regional RV longitudinal strain is altered in the free wall and mid and basal septum in patients with acute pulmonary embolism 3. Strain rates are reduced in the RV free wall 3. RV free wall longitudinal strain (FWS) is reduced in patients with pulmonary embolism, and its addition to traditional measures of RV size and function improves sensitivity and specificity for diagnosis of pulmonary embolism 5.