Introduction and Overview
Echocardiography on specific casesMinilecture. June 3, 2005
INTRODUCTION & OVERVIEW
Echocardiography has emerged as the most frequently performed
imaging test in cardiology. The examination is inexpensive and
provide definitive assessment of both cardiac anatomy and
hemodynamics. Through the use of Doppler echocardiography, it is
possible to define both the etiology and the severity of valvular
stenosis and regurgitation, as well as intracardiac shunts.
The greatest limitation to echocardiography is that both image
acquisition and interpretation are extremely dependent upon the
expertise of the user. (operator dependent)
In routine examination, Motion mode (M-mode), 2 Dimension (2D)
and Doppler examination are always be performed to evaluate cardiac
anatomy and hemodynamics within the cardiac chambers.VALVULAR HEART
DISEASE
Over the last four decades echocardiography has emerged as the
definitive procedure for evaluating patients with all varieties of
valvular heart disease
Mitral Stenosis (MS)
The etiology of MS are: 1. Sequalae of rheumatic fever. 2.
Congenital abnormalities, such as
parachute mitral valve, and 3. Severe mitral annular
calcification that encroaches onto the leaflets, reducing their
mobilityThe features of MS are: 1. Diastolic doming of the valve
and 2. Calcification and immobility of theleaflets. Another
features of mitral stenosis such as: 1.Left atrial enlargement.
2.Atrial fibrillation. 3.Thrombosis (better in transthoracal
approach), and 4. Pulmonary hypertension w/o tricuspid
regurgitation are due to secondary effect of MS. Evaluating the
Severity of MS
1.Planimetry of the mitral stenotic orifice by transthoracic
echocardiography .2. Doppler evaluations are the most frequent
method to evaluate the mitral valve area and its pressure gradient
as well.
The mitral score has been using as a routine examination to
evaluate the mitral valve and to make a treatment recommendations
as well.
Mitral Regurgitation (MR)The etiology of MR are: 1. Myxomatous
degeneration (the most common in the US), 2. Rupture of
the chordae 3. Rheumatic mitral regurgitation (shortening and
immobility of the leaflet) 4. Cleft mitral leaflet (congenital) 5.
A secondary consequence of left ventricular dilatation. 5.Ischemic
cardiac disease (scarring, retraction of the subvalvular apparatus)
6. Rupture of the papillary muscle 7.Mitral endocarditis.
Evaluating the Severity of MRThe measurement methods are : 1.
Measurement of the jet area. 2. Measurement of the proximal
convergence. (more accurate) 3. Calculated from the measurements of
forward mitral and aortic stroke volume.Secondary Effects of MR
1.`Left atrial enlargement (frequently leading to atrial
premature beats and atrial fibrillation), 2. Pulmonary hypertension
and 3. Ventricular dilatation ( with both overt and latent left
ventricular dysfunction) Aortic Stenosis (AS)The etiology of aortic
stenosis are: 1. Bicuspid aortic valve. 2. Rheumatic heart disease
and 3. Calcific degeneration in older age is the most common (in
the United States)
Quantifying the Severity of AS
Planimetry of the valve (best measured by transthoracic
echocardiography)
Attempt to quantify the severity of AS precisely both peak and
mean gradients should be measured and reported.
Aortic Regurgitation (AR)The etiology of AR are: (many of the
same causes as aortic stenosis)
1. Congenitally bicuspid valve. 2. Rheumatic aortic valve 3.
Prominent dilatation of the aortic root. 4. Aortic dissection, and
5. Endocarditis Evaluating the Severity of ARThere are a variety of
methods but none of them particularly precise. 1. Fluttering of the
anterior mitral leaflet (as a clue) 2.Measurement of the size of
the regurgitant jet. 3. Semiquantitative assessment of
regurgitation (which is more accurate) 4. Measurement of the AR and
5. The proximal convergence method
CARDIOMYOPATHY
Hypertrophic Cardiomyopathy The characterization of hypertrophic
cardiomyopathy are: 1. Severe asymmetric septal hypertrophy and 2.
Systolic anterior motion (SAM) of the mitral valve. 3. Abnormal
diastolic function.
Dilated Cardiomyopathy
The etiology of Dilated cardiomyopathy are: 1. Idiopathic
generalized process. 2. End stage of ischemic cardiac disease. The
manifestation of dilated cardiomyopathy is impairment of both
diastolic and systolic function
Hypertensive Cardiomyopathy
The significant features of hypertensive cardiomyopathy is
concentric left ventricular hypertrophy. A delayed filling pattern
(diastolic dysfunction) may reveal and in the end stage,
pseudonormalization or a restrictive pattern may ensue.
CORONARY ARTERY DISEASE (CAD)
Acute chest pain and myocardial infarction.Echocardiography is
extremely helpful in evaluating patients with chest pain. A
documentation of completely normal wall motion during actual pain
virtually excludes cardiac ischemia as the cause of the pain.
Echocardiography is also the diagnostic procedure of choice for
many of the mechanical complications of myocardial infarction
(ventricular septal defect, papillary muscle rupture)
Chronic Coronary Disease
Stress echocardiography is a helpful method in investigating the
presence of CAD but milder grades of coronary stenosis may not
produce any regional wall motion abnormality. Stress
echocardiography has been proven to be of particular value in
certain cases, such as women, left bundle branch block, and left
ventricular hypertrophy. Ventricular wall motion must be
interpreted in a structured manner with an appreciation for the
usual perfusion territories of the coronary arteries.
.The new 17-segment adopted by the Cardiac Imaging Committee of
the Council on Clinical Cardiology of the American Heart
AssociationStress echocardiography has been proven to be of great
prognostic value in a variety of clinical settings. The presence of
normal wall motion at high exercise levels is associated with an
extremely low event rate moreover exercise echocardiography is a
particularly useful technique for the assessment of prognosis after
acute events. Pharmacologic stress echocardiography has also been
shown to be of value in risk stratification following myocardial
infarction and for for identifying high-risk patients with planned
major noncardiac surgery .In chronic ischemic heart disease,
ischemia and the extent of abnormal wall motion are independent
predictors of cardiac death .