How to interpret an echo report?

How to interpret an echo report?

(Please see the YouTube video above for illustrations)

Echocardiogram, often called just echo in short is ultrasound imaging of the heart. Though the actual types of details mentioned in echo report may vary between institutions and even persons reporting it, in general there are several common aspects. Reports of children with birth defects of the heart will have a different pattern. This discussion is mainly on an echo report from a general cardiology setup rather than a specialized report.

In addition to details of identification and date of procedure, reason for the test and the quality of images are usually mentioned in the beginning of the report. Quality of images may be poor in those with lung disease and in obese individuals. Finer details in the report should be interpreted with caution when the image quality is reported as poor or as poor echo window. Poor echo window means that good quality images were not obtained during the study. This is common in those with chronic obstructive lung disease as the hyperinflated lungs overlap the heart in parasternal and apical echo windows. The usual echo windows are the parasternal, apical, subcostal and suprasternal. Each window allows the imaging of certain cardiac structures. In chronic obstructive lung disease when the parasternal and apical windows are poor, subcostal window is usually good. Lungs do not come in the way of the ultrasound beam in the subcostal view. Air in the lungs do not permit transmission of the ultrasound beam to the heart. So the usual echocardiographic windows are regions where the overlap by the lungs is minimal.

Chamber sizes and measurement of thickness of chamber walls are either given as tables or the relevant picture showing the measurements printed on the report. In some reports, reference normal values are also provided. While looking at reports of children, measurements should be interpreted considering the physical size of the child as heart chambers grow in size as the child grows.

In addition to the measurements, there will also be a qualitative report on whether the chambers are enlarged or thickened and whether they are contracting well or not. An enlarged cardiac chamber is mentioned as dilated, while a thickened one is mentioned as hypertrophied. In some cases it may be both dilated and hypertrophied. Hypertrophy with dilatation of cavity is called eccentric hypertrophy while hypertrophy without dilatation is concentric hypertrophy. When the interventricular septum is hypertrophied disproportionately compared to the posterior wall of the left ventricle, it is known as asymmetric septal hypertrophy, usually seen in hypertrophic cardiomyopathy.

Details about all four cardiac valves will be mentioned in the echo report. In case of aortic valve, if it is congenitally abnormal it may be bicuspid instead of the normal tricuspid valve. Very rarely the aortic valve can also be quadricuspid. Morphology of the valves and their opening and closing will be assessed during echocardiography. Valve thickening and calcification are often noted in stenotic valves. Stenotic valves also dome while opening due to commissural fusion. In case of mitral valve, commissural fusion causes paradoxical anterior motion during diastole instead of the normal posterior opening movement. In hypertrophic obstructive cardiomyopathy, anterior mitral leaflet may move anteriorly in systole, producing obstruction of the left ventricular outflow tract. This is known as systolic anterior movement or SAM of the mitral valve. Thickening, fibrosis and calcification of the subvalvar apparatus is common in rheumatic mitral valve disease. Atrioventricular valves can prolapse into the atria during systole production regurgitation. In mitral valve prolapse, the valve may also be thickened due to myxomatous deposits. In elderly with degenerative mitral valve disease and in those with chronic kidney disease, the mitral annulus may be grossly thickened and calcified.

Dimensions of the great vessels aorta and pulmonary artery have to be checked. Dilated aortic root can produce aortic regurgitation due to poor coaptation of aortic leaflets. In an emergency situation, aortic dissection flap may also be noted in the ascending aorta rarely. Pulmonary artery is dilated in left to right shunts and pulmonary hypertension. Rarely it could also be idiopathic dilatation of pulmonary artery.

Parts of the superior and inferior vena cavae also can be imaged by echocardiography. Inferior vena caval size is often used at the bedside to assess hydration status for guiding fluid therapy. Normal inferior vena cava collapses in inspiration, with at least 50% decrease in dimensions. If the inferior vena cava is dilated and does not collapse in inspiration, it is called ‘plethora of inferior vena cava’. Inferior vena caval plethora indicates high right atrial pressure.

Pulmonary veins can be seen joining the left atrium. Usually only three pulmonary veins are imaged in the adult. Pulmonary veins will not be seen joining the left atrium in case of total anomalous pulmonary venous drainage. Sometimes only one or two may join the right atrium in partial anomalous pulmonary venous drainage.

While coming to function of the heart, the concentration is often on the left ventricle, which pumps blood to the whole body. An important value in the report is the ejection fraction. Ejection fraction is the fraction of the blood from the full left ventricle which is ejected out during each contraction. Suppose after filling when the left ventricle relaxes in diastole, it has 100 ml of blood. If 70 ml is pumped out by the next contraction or systole, the ejection fraction will be 70%. An ejection fraction below 50% is considered below normal. The lower the ejection fraction, the poorer the pumping function of the heart. A normal left ventricular ejection fraction is usually reported as good left ventricular function. If it is severely impaired, it is noted as severe left ventricular dysfunction. When the left ventricle is stiff and relaxes poorly in diastole, it is reported as left ventricular diastolic dysfunction. Left ventricular diastolic dysfunction is quite common as age advances.

Another important aspect is the contraction of each region of the left ventricle. If all regions of the left ventricle contracts normally, it is reported as ‘no regional wall motion abnormality’. If a particular region contracts poorly, it is reported as ‘hypokinetic’. A region which is not contracting at all is reported as ‘akinetic’. Sometimes a region might bulge out when all other regions are contracting. Such a region is called ‘dyskinetic’. Regional wall motion abnormalities are common after a myocardial infarction. When a blood vessel supplying a region of the heart muscle is blocked, that region shows a regional wall motion abnormality of any of the above mentioned types. In conditions like dilated cardiomyopathy, instead of regional wall motion abnormality, the whole left ventricle is hypokinetic. Then it is called global hypokinesia.

Defects in interventricular and interatrial septa will be mentioned if present, along with the location, size and shunt across it. If there is no defect, it is reported as intact interatrial and interventricular septa. Presence of a patent ductus arteriosus will also be mentioned similarly. Estimated right ventricular systolic pressure is mentioned as RVSP, calculated from the velocity of the tricuspid regurgitation jet by Doppler echocardiography. Indirect evidence regarding pulmonary hypertension will be obtained by the size of pulmonary artery, movement pattern of pulmonary valve and hypertrophy/dilatation of the right sided cardiac chambers. In such cases, the shunt may be right to left or bidirectional instead of the usual left to right. Locations of atrial septal defect are sinus venosus, secundum and primum, starting from the upper end of the septum downwards. Primum atrial septal defect is usually associated with regurgitation of atrioventricular valves. Locations of ventricular septal defects may be mentioned as outlet, perimembranous, muscular or inlet. Outlet is just below the pulmonary valve and inlet near the atrioventricular valves.

Any of the heart valves can also be abnormal, either as a birth defect or acquired later in life due to diseases. If a valve is narrowed, it is called stenosis. There can be mitral stenosis, aortic stenosis, tricuspid stenosis and pulmonary stenosis or a combination of these. Leak in a valve is called regurgitation. So there can be mitral regurgitation, aortic regurgitation, tricuspid regurgitation and pulmonary regurgitation or a combination of these. There can also be stenosis and regurgitation in the same valve. Stenosis can be graded as mild, moderate and severe depending on the severity. Area of the narrowed valve may be mentioned in certain cases. Regurgitation can be graded as trivial, mild, moderate and severe. Trivial regurgitations, as the name implies, are usually ignored, especially in relation to the right sided valves (pulmonary and tricuspid). Pressure gradients across the valves will be mentioned when the valve is narrowed. The gradient increases as the severity of the narrowing increases. Gradients are measured by Doppler echocardiography.

When there is a leak in the tricuspid valve, the pressure difference between the right ventricle and right atrium can be calculated. This is usually mentioned as TR (tricuspid regurgitation) gradient. Usually a nominal value of 10 is added to this gradient and mentioned as the estimated right ventricular systolic pressure or RVSP. An elevated RVSP implies an increased pressure in the pulmonary artery (pulmonary hypertension), if the pulmonary valve is not obstructed.

If there is fluid collection in the pericardial cavity, it is reported as pericardial effusion. The estimated amount of the collection will be reported as mild, moderate or large. Diastolic collapse of the right atrium and right ventricle may be noted in cardiac tamponade. Gross thickening and calcification of the pericardium may occur in chronic constrictive pericarditis.

Vegetations attached to the valves can be infective or non-infective. Non-infective vegetations may be seen in Libman-Sacks endocarditis of systemic lupus erythematosus and marantic endocarditis. Marantic endocarditis is nonbacterial thrombotic endocarditis seen in advanced malignancy.

Commonest cardiac tumors are the myxomas, of which left atrial myxoma is the commonest. Left atrial myxoma usually prolapses into the left ventricle in diastole as it has a long stalk. Rhabdomyomas may be noted in the ventricles, especially in infants.

After the descriptive report and the measurements, the final conclusion is usually reported at the end of the report. In case of a normal adult study it may read as: No regional wall motion abnormality, Good left ventricular systolic function. Regional wall motion abnormality may be written in short as RWMA also. If abnormalities have been detected, the conclusion part will be larger and include the salient parts of the echo study. For example, in a person with a ventricular septal defect, it may read as: Congenital Heart Disease, Large Perimembranous Ventricular Septal Defect, Left to Right Shunt, Moderate Pulmonary Arterial Hypertension, Good Biventricular Function.