Adult Echocardiography (AE) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Left ventricular ejection fraction

Ejection fraction equals end-diastolic volume minus end-systolic volume divided by end-diastolic volume; normal is approximately 55-70% by Simpson's biplane method.

Cardiac output formula

Cardiac output equals stroke volume multiplied by heart rate; stroke volume can be derived from LVOT area times LVOT velocity-time integral.

Right ventricular systolic pressure

RVSP equals 4 times the square of peak tricuspid regurgitation velocity plus right atrial pressure estimated from IVC size and collapse.

Normal mitral valve area

The normal mitral valve orifice is 4-6 cm²; an area below 1.5 cm² indicates moderate to severe mitral stenosis.

Diastolic function grades

Grade 1 shows E/A below 0.8; grade 2 shows E/A 0.8-1.5 with elevated filling pressures; grade 3 shows E/A above 2 with restrictive filling.

Seventeen segment model

The left ventricle is divided into six basal, six mid, four apical segments, and an apical cap; the apex is assigned to the LAD territory.

Nyquist limit

The Nyquist limit is half the pulse repetition frequency; Doppler shifts above it alias and wrap to the opposite direction on spectral display.

Aliasing

Aliasing occurs when the Doppler shift exceeds the Nyquist limit, producing wrap-around or ambiguous color and spectral display; increase PRF or lower frequency.

Axial resolution

Axial resolution equals spatial pulse length divided by two; higher frequency and fewer cycles per pulse improve it to approximately 0.5-1 mm.

Doppler equation

Doppler shift equals 2 times transducer frequency times blood velocity times cosine of the angle, divided by tissue propagation velocity.

Attenuation in soft tissue

Attenuation is about 0.5 dB per centimeter per megahertz one-way; higher frequencies improve resolution but reduce penetration.

Mechanical index

Mechanical index equals peak negative pressure in megapascals divided by the square root of frequency in megahertz; it estimates cavitation risk.

Frame rate determinants

Frame rate equals pulse repetition frequency divided by lines per frame; color Doppler and wider sectors reduce frame rate.

Parasternal long-axis view

This view shows the right ventricle anteriorly, left ventricle, aortic root, and left atrium; LVOT diameter is measured in mid-systole.

Simpson's biplane method

End-diastolic and end-systolic endocardial borders are traced in apical four- and two-chamber views to calculate LV volumes and ejection fraction.

Pulsed-wave Doppler

PW Doppler uses a sample volume to detect low velocities with range resolution but aliases above the Nyquist limit; it is used for LVOT and mitral inflow.

Continuous-wave Doppler

CW Doppler records all velocities along the beam without aliasing but without range resolution; it is used for high-velocity jets such as aortic stenosis.

Tissue Doppler imaging

Tissue Doppler measures low-velocity myocardial motion at the mitral annulus; septal e' below 7 cm/s suggests impaired relaxation.

Doppler angle correction

Flow velocity is accurate when the ultrasound beam is within 60 degrees of flow; angle correction applies to vascular flow, not cardiac valve jets.

Continuity equation

Aortic valve area equals LVOT area times LVOT velocity-time integral divided by aortic valve velocity-time integral; it is used for aortic stenosis severity.

Severe aortic stenosis

Severe aortic stenosis is defined by peak velocity at least 4 m/s, mean gradient at least 40 mmHg, or valve area below 1.0 cm².

Pressure half-time

Mitral valve area equals 220 divided by pressure half-time in milliseconds; a half-time above 220 ms suggests severe mitral stenosis.

Vena contracta

The narrowest jet width just downstream of a regurgitant orifice; a vena contracta of at least 0.7 cm indicates severe mitral regurgitation.

PISA method

Proximal isovelocity surface area calculates effective regurgitant orifice area using flow convergence radius, aliasing velocity, and peak regurgitant velocity.

Aortic regurgitation half-time

A pressure half-time below 200 ms suggests severe aortic regurgitation; holodiastolic flow reversal in the descending aorta supports severity.

Prosthetic valve gradients

Normal mean gradients are generally below 20 mmHg for aortic and below 5 mmHg for mitral prostheses; higher values suggest obstruction or mismatch.

Hypertrophic cardiomyopathy

Asymmetric septal hypertrophy of at least 15 mm with systolic anterior motion of the mitral leaflet can cause dynamic LVOT obstruction and gradient at least 30 mmHg.

Cardiac amyloidosis

Amyloid shows thickened ventricles, granular sparkling texture, apical sparing of longitudinal strain, and low ECG voltage relative to wall thickness.

Cardiac tamponade

Tamponade shows a pericardial effusion with right atrial systolic collapse, right ventricular diastolic collapse, IVC plethora, and respiratory flow variation.

Constrictive pericarditis

Constrictive pericarditis shows pericardial thickening, septal bounce, annulus paradoxus, and medial e' greater than lateral e' on tissue Doppler.

Dilated cardiomyopathy

Dilated cardiomyopathy shows LV dilation and reduced ejection fraction, often with functional mitral regurgitation; LV thrombus may require anticoagulation.

Aortic dissection flap

An intimal flap in the ascending aorta indicates Stanford type A dissection, a surgical emergency; color Doppler may show true and false lumens.