From the Guidelines
Pressure overload and volume overload have distinct echocardiographic features on 2D transthoracic echocardiography (TTE), with pressure overload primarily manifesting as concentric hypertrophy and volume overload presenting as eccentric hypertrophy. The differences between these two conditions can be identified by examining the ventricular wall thickness, chamber size, and left ventricular mass. Pressure overload, which occurs in conditions such as hypertension or aortic stenosis, leads to an increase in ventricular wall thickness, typically exceeding 11mm in adults, with a preserved or reduced cavity size 1. In contrast, volume overload, which occurs in conditions such as mitral or aortic regurgitation, results in chamber dilation with normal or mildly increased wall thickness, and an increase in left ventricular end-diastolic dimension beyond normal limits (>5.3cm in men, >4.8cm in women) 1.
Key Features of Pressure and Volume Overload
- Pressure overload:
- Concentric hypertrophy
- Increased ventricular wall thickness (>11mm in adults)
- Preserved or reduced cavity size
- Increased left ventricular mass
- Elevated ratio of wall thickness to cavity radius (relative wall thickness)
- Volume overload:
- Eccentric hypertrophy
- Chamber dilation
- Normal or mildly increased wall thickness
- Increased left ventricular end-diastolic dimension (>5.3cm in men, >4.8cm in women)
- Increased left ventricular mass
- Normal relative wall thickness
Clinical Implications
Recognizing the distinct echocardiographic features of pressure and volume overload is essential for identifying the underlying hemodynamic stress and guiding appropriate management strategies. The American Heart Association recommends evaluating right-sided heart failure using a scientific statement that includes the assessment of right ventricular geometry and function 1. Additionally, the American Society of Echocardiography and the European Association of Cardiovascular Imaging provide recommendations for cardiac chamber quantification by echocardiography in adults, which includes measuring left ventricular volumes using 2D echocardiography 1.
Echocardiographic Evaluation
Echocardiography is a valuable tool for evaluating cardiac structure and function, and can provide important information about the presence and severity of pressure and volume overload. The use of 2D transthoracic echocardiography (TTE) is recommended for evaluating left ventricular volumes and function, and for assessing the presence of valvular regurgitation or stenosis 1.
From the Research
Differences between Pressure Overload and Volume Overload
The differences between pressure overload and volume overload can be observed on a 2-dimensional Transverse Thoracic Echocardiogram (2D TTE) through various parameters:
- Left ventricular (LV) wall thickness and dimensions: In pressure overload, the LV wall thickness is increased, whereas in volume overload, the LV dimensions are increased 2.
- Interventricular septal (IVS) configuration: End-systolic flattening of the IVS is a specific finding in patients with right ventricular (RV) pressure overload 3.
- Left ventricular systolic function: Myocardial contractility is depressed in pressure overload, whereas it is preserved in volume overload 4.
- Echocardiographic determinants: The ratio of IVS radius of curvature to left ventricular free wall radius of curvature (IVSr/FWr) correlates well with RV peak systolic pressure/LV peak systolic pressure ratio in end systole and RV end-diastolic pressure/LV end-diastolic pressure ratio in end diastole 3.
Echocardiographic Features
Echocardiographic features of pressure overload and volume overload include:
- Increased LV wall thickness and relative wall thickness in pressure overload 2
- Increased LV dimensions and volumes in volume overload 4
- Depressed myocardial contractility in pressure overload, whereas it is preserved in volume overload 4
- Specific patterns of myocardial deformation (strain) in certain myocardial pathologies, such as amyloidosis, hypertrophic cardiomyopathy, or Chagas disease 5
Clinical Implications
The clinical implications of pressure overload and volume overload include:
- Different patterns of left ventricular remodeling and hypertrophy in response to pressure and volume overload 6
- Significant reductions in systolic left ventricular wall stress (LVWS) after transcatheter aortic valve replacement (TAVR) in patients with aortic stenosis 6
- Significant reductions in diastolic LVWS after MitraClip (MC) in patients with mitral regurgitation 6
- Inverse correlation between baseline systolic LVWS and 6-minute walk test (6MWT) in patients with aortic stenosis undergoing TAVR 6