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Echocardiography 5 minutes before starting

Cardiac function and PA pressure

—Echocardiographic examinations

—Cardiac function and PA pressure

Systolic LV function
Diastolic LV function
Longitudinal function
RV function
PA pressure

—Examples of pathological
findings

Diastolic LV function

A prerequisite to assessment of diastolic LV function is the capability of the method to measure pressures, and Doppler echocardiography is only able to measure velocities. Only through application of formulas, as the modified Bernoulli equation (V² · 4 = ΔP) it is possible to estimate pressure gradients.

Different alternative possibilities to assess diastolic LV function were developed in the last decades. However, these tools made diagnosis of global diastolic LV dysfunction not always easy and clear. Sometimes different parameters just do not match to each other, or can not be correctly interpreted in case of atrial fibrillation or flutter.

A new equation enables non-invasive assessment of PCWP, the Nagueh-Formula: 1,9 + (1,24 · E/E') = PCWP, that could make estimation of diastolic function in some way easier, since PCPW ≈ mLAP ≈ LVEDP. Here an online calculator from the Canadian Society of Echocardiography, to calculate PCWP.

Classic parameters are still in current use and will be presented below. Current guidelines of the American Society of Echocardiography concerning diastolic function can be found here.

Mitral inflow velocities examination

Pulsed wave Doppler (PW-Doppler) allows the measurement of velocities at the level of the sample volume. Two flow velocity envelopes can be seen during diastole in persons with sinus rhythm: the E-wave, representing the early, passive filling of the left ventricle, and the A-wave, that happens late in diastole, representing the active filling, the atrial contraction.

Left: PW-Doppler sample volume is placed at the tips of the mitral valve in the left ventricle.

Right: normal mitral velocities, inflow coming from the left atrium in the left ventricle during diastole, shown here with color Doppler.

Left: pulsed wave (PW) Doppler spectral display shows an E-wave with higher velocities, as well as an end-diatolic A-wave with lower velocities.

Right: an A-wave twice as large as the E-wave indicates impaired LV relaxation.

Mitral annular velocities examination

Slow wall velocities can be assessed with Tissue Doppler Imaging (TDI). The sample volume, when placed at the medial mitral annulus, shows slower velocities as when placed at the lateral annulus. The E/E' relationship will be different according to each case, making more difficult the interpretation of results.

Left: PW-TDI sample volume is place at the level of the lateral mitral annulus.

Right: normal LV wall velocities during cardiac cycle, here a color coded display.

Left: spectral tissue Doppler (TDI) display shows an antegrade sys- tolic, and two retrograde waves, E' (passive LV filling) and A'-wave (atrial contraction).

Right: E' and A' waves show here a reversed relationship. In com- bination with other parameters this could indicate an impairment of relaxation or a pseudonormal pattern.

Pulmonary venous flow examination

Pulmonary venous flow velocities can be assessed with PW-Doppler. Localization of pulmonary veins with color Doppler is relatively easy, and allows to place sample volume at the right position.

Usefulness of the examination of pulmonary venous for estimation of left atrial pressure was shown by Kuecherer H et al. Circulation 1990;82:1127-1139.

Left: pulmonary venous flow can be assessed with PW-Doppler from the apical four-chamber view.

Right: normal pulmonary vein velocities into the left atrium during cardiac cycle, here shown with color Doppler.

Left: PW Doppler spectral display shows a larger systolic (S), a diastolic (D) and a smaller end- diastolic wave (AR), the atrial contraction.

Right: the shift towards diastole, with a predominant diastolic wave (D) speak for an increase of LA pressure. This can be documented in a case of impairment of LV compliance (restrictive pattern).

Velocity of flow progression (Vp)

Velocity of flow progression (Vp) during diastole can be assessed with color Doppler M-mode. A Vp > 50 cm/s can be considered as normal. A E/Vp ≥ 2.5 in a patient with impaired systolic left ventricular can predict a PCWP > 15 mmHg.

Left: a narrow color Doppler sector is placed between mitral valve and LV apex. The M-mode examination line is place through the center of the LV entrance flow.

Right: here a normal case. The Nyquist-limit should be reduced if no spontaneous aliasing is ob- served. The first aliasing velocity front should be measured.

Left: higher velocities at the A- wave can be seen at impairment of LV relaxation, even without changing the Nyquist-limit.

Right: here an example of a restrictive pattern. The Vp is 27 cm/s and hence clearly under the limit of 45 cm/s.

Echocardiographic parameters to assess diastolic LV function

The concept of Rosetta Stone for diastole was presented first by Rick A. Nishimura und A. Jamil Tajik, J Am Coll Cardiol 1997;30:8-18. It is very important to understand, that the diagnosis of diastolic LV dysfunction can not be made with one parameter alone.

A patient with dyspnea, preserved systolic LV function, dilated left atrium and elevated pulmonary artery systolic pressure, without any significant mitral valve disease that could explain these findings, is the patient that requires an intensified search for diastolic LV dysfunction.

I: impaired relaxation, II: moderate diastolic dysfunction (pseudonormal), III: restrictive left ventricular filling (impaired LV compliance), ECG: electrocardiogram, MI: mitral inflow, MA: mitral annular velocities, PVF: pulmonary venous flow, Vp: velocity of flow progression, LA: left atrium, PASP: pulmonary artery systolic pressure.

A very good dynamic presentation of diastolic LV dysfunction ca be found here: Dr. Guido Giordano - Catania, Italia.

Algorithm for practical assessment of diastolic LV function

NYHA: New York Heart Association classification to stages of heart failure, LV-EF: left ventricular ejection fraction, E/E': relationship between maximal values of passive mitral inflow (E, PW-Doppler) and lateral early diastolic mitral annular velocities (E', TDI), LV-EDP: end-diastolic LV pressure, PASP: pulmonary artery systolic pressure.