Assessment of left ventricular geometry and dimensions
The examination begins with measuring the end-diastolic dimension (EDD) and wall thickness. In normal findings, the chamber is not dilated (e.g., EDD 5.4 cm). Thickening of the interventricular septum (IVS) and posterior wall exceeding 1.1 cm serves as a sign of hypertrophy.
To specify the type of remodeling, the following are calculated:
- Left ventricular mass index (LVMI): values exceeding 115 g/m² in men confirm the presence of hypertrophy.
- Relative wall thickness: a parameter above 0.42 indicates a concentric remodeling pattern.
LV dimensions directly depend on hemodynamics. In acute mitral regurgitation (e.g., due to ruptured chordae tendineae — chordae tendineae), heart dimensions may remain normal. However, with chronic volume overload, the LV and left atrium dilate, acting as a reservoir.
Systolic function and contractility
Global myocardial contractility is traditionally assessed using ejection fraction (EF), calculated via the Simpson method. EF represents the percentage of blood volume ejected into the aorta per contraction. The absence of regional wall motion abnormalities on echocardiography helps rule out scar tissue from past myocardial infarction or severe ischemia.
In early mitral regurgitation, LV stroke volume and EF increase compensatorily. If the decompensation stage sets in, the effective (forward) stroke volume decreases, leading to the clinical presentation of heart failure.
Left ventricular diastolic function
Diagnosis of diastolic dysfunction (impaired LV relaxation) is based on analyzing the blood flow velocity spectrum across the mitral valve in early diastole using Doppler echocardiography.
| Parameter | Description |
|---|---|
| E peak | Early diastolic filling blood flow |
| A peak | Atrial systolic blood flow |
| Tissue Doppler (e') | Assessment of myocardial structure motion to calculate the E/e' ratio |
Type 2 diastolic dysfunction (pseudonormal pattern) is characterized by an E/e' ratio greater than 9 (e.g., 13) and an E-wave deceleration time of about 160 ms. Combined with normal EF, dyspnea, and elevated NT-proBNP levels, these findings are criteria for heart failure with preserved ejection fraction (HFpEF).
Doppler echocardiography in the assessment of valvular heart disease and overload
Doppler ultrasound is indispensable for detecting valvular pathologies that affect left ventricular function:
- Assessment of stenosis: M-mode echocardiography visualizes the characteristic motion of mitral valve leaflets, while Doppler allows for the calculation of orifice area, peak velocity, and pressure gradient. Severe aortic stenosis is characterized by a mean gradient >40 mm Hg, peak velocity >4.0 m/s, and valve area <1 cm².
- Assessment of regurgitation: Color flow mapping directly visualizes the backflow jet (e.g., from the aorta into the LV in diastole or from the LV into the left atrium in systole). Quantitative pulse-wave Doppler calculates the regurgitant volume.
- Infective endocarditis: Echocardiography assesses LV dimensions and function, detects vegetations (a direct sign, found in >50% of cases), and evaluates destruction of the valvular apparatus, including the formation of a flail leaflet.
Remembering the phases of diastolic flow is easy using the letters: E peak — Early diastole begins (early, passive filling), A peak — Active atrial systole.
Class and exam questions
Why is the left ventricle not enlarged in acute severe mitral regurgitation?
Sudden rupture of chordae or papillary muscles results in acute volume overload. The left atrium and left ventricle do not have time to physically dilate (stretch), leading to a sharp rise in pressure and pulmonary edema with nearly normal heart dimensions.
How to confirm concentric hypertrophy via echocardiography?
Two parameters must be assessed: the left ventricular mass index must be elevated (e.g., >115 g/m² in men), and the relative wall thickness index must be greater than 0.42.
What is the pseudonormal pattern of diastolic dysfunction?
This is Type 2 myocardial relaxation impairment. In this pattern, the E and A blood flow velocity peaks may appear normal, but the tissue Doppler parameter E/e' is significantly elevated (greater than 9), indicating high mean pressure in the left atrium.
What else to study on this topic
- Severity criteria for aortic and mitral stenosis based on Doppler echocardiography
- Echocardiographic signs of mitral valve prolapse and chordal rupture
- Non-invasive assessment of systolic pulmonary artery pressure (SPAP) in LV pathologies
- Diagnostic algorithm for heart failure with preserved ejection fraction (HFpEF)
- Left atrial dilation as a structural substrate for atrial fibrillation
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