Echocardiogram Basics

ECHOCARDIOGRAM

ECHOCARDIOGRAMBYPRASANTH.K

DescriptionIt is a type of ultrasound test that uses high-pitched sound waves to produce an image of the heart. The sound waves are sent through a device called a transducer and are reflected off the various structures of the heart. These echoes are converted into pictures of the heart that can be seen on a video monitor.PRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE

COMPONENETS

Pulse generator - applies high amplitude voltage to energize the crystals Transducer - converts electrical energy to mechanical (ultrasound) energy and vice versa Receiver - detects and amplifies weak signals Display - displays ultrasound signals in a variety of modes Memory - stores video display

PRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE

INDICATIONInformation on valvular structure and motion.Cardiac chamber size and contentsVentricular muscle , septal motion and thicknessEjection fractionPericardial sacAscending aortaPRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE

Cont.Symptoms potentially due to suspected cardiac etiology.

Assessment of known or suspected adult congenital heart disease.

Evaluation of suspected complication of myocardial ischemia/infarction.

Evaluation of valvular or structural heart disease.

Initial evaluation of prosthetic valve for establishment of baseline after placement.PRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE

CONT..Initial evaluation of suspected infective endocarditis with positive blood cultures or a new murmur.

Evaluation of cardiac mass (suspected tumor or thrombus).

Evaluation of pericardial conditions: i.e. pericardial effusion, constrictive pericarditis.

Initial evaluation of known or suspected cardiomyopathy.PRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE

PROCEDUREA standard echocardiogram is also known as a transthoracic echocardiogram (TTE), or cardiac ultrasound. The subject is asked to lie in the semi recumbent position on his or her left side with the head elevated.The left arm is tucked under the head and the right arm lies along the right side of the body


Standard positions on the chest wall are used for placement of the transducer called echo windows


Parasternal Long-Axis View (PLAX)Transducer position: left sternal edge; 2nd 4th intercostal spaceMarker dot direction: points towards right shoulderMost echo studies begin with this viewIt sets the stage for subsequent echo viewsMany structures seen from this view


Parasternal Short Axis View (PSAX)Transducer position: left sternal edge; 2nd 4th intercostal spaceMarker dot direction: points towards left shoulder(900 clockwise from PLAX view)By tilting transducer on an axis between the left hip and right shoulder, short axis views are obtained at different levels, from the aorta to the LV apex.Many structures seen


Papillary Muscle (PM)levelPSAX at the level of the papillary muscles showing how the respective LV segments are identified, usually for the purposes of describing abnormal LV wall motion LV wall thickness can also be assessed


Apical 4-Chamber View (AP4CHTransducer position: apex of heartMarker dot direction: points towards left shoulderThe AP5CH view is obtained from this view by slight anterior angulation of the transducer towards the chest wall. The LVOT can then be visualised


Apical 2-Chamber View (AP2CH)Transducer position: apex of the heartMarker dot direction: points towards left side of neck (450 anticlockwise from AP4CH view)Good for assessment ofLV anterior wallLV inferior wall


SubCostal 4 Chamber View(SC4CH)Transducer position: under the xiphisternumMarker dot position: points towards left shoulderThe subject lies supine with head slightly low (no pillow). With feet on the bed, the knees are slightly elevatedBetter images are obtained with the abdomen relaxed and during inspirationInteratrial septum, pericardial effusion, desc abdominal aorta


Suprasternal ViewTransducer position: suprasternal notchMarker dot direction: points towards left jawThe subject lies supine with the neck hyperexrended. The head is rotated slightly towards the leftThe position of arms or legs and the phase of respiration have no bearing on this echo windowArch of aorta


TYPESTransthoracic echocardiogram Standard echocardiogram. It is a painless test similar to X-ray, but without the radiation. A hand-held device called a transducer is placed on the chest and transmits high frequency sound waves (ultrasound). These sound waves bounce off the heart structures, producing images and sounds to detect heart damage and disease.PRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE

CONT..Transesophageal echocardiogram (TEE)This test requires that the transducer be inserted down the throat into the esophagus (the swallowing tube that connects the mouth to the stomach).

The esophagus is located close to the heart, clear images of the heart structures can be obtained without the interference of the lungs and chest.TEE provides superior image quality, particularly for posterior cardiac structures which are nearer to the esophagus and less well visualized on transthoracic echocardiographyPRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE


NPO for six hours before the test Dentures will be removed. An intravenous line (IV) will be inserted into a vein ,so that medications can be delivered during the test.The electrodes are attached to an electrocardiograph monitor that charts heart's electrical activity during the test.A blood pressure cuff will be placed on to monitor blood pressure during the test.A pulse oximeter, will be placed finger to monitor the oxygen level of blood during the test.


CONT..A mild sedative will be given through IV. A dental suction tip will be placed into mouth to remove any secretions. A thin, lubricated endoscope (viewing instrument) will be inserted into mouth, down throat, and into esophagus. Swallow at certain times to help pass the endoscope. Once the endoscope is positioned, pictures of the heart are obtained at various angles.


CONTRAINDICATIONSUnrepaired tracheoesophageal fistulaHistory prior esophageal surgeryEsophageal obstruction or strictureEsophageal varices or diverticulumPerforated hollow viscus Gastric or esophageal bleedingPoor airway control Vascular ringSevere respiratory depression Oropharyngeal pathologyUncooperative, unsedated patientSevere coagulopathyCervical spine injury


COMPLICATIONS Respiratory compromiseLaryngospasmHypoxia. Bronchospasm. Cardiovascular complications:Tachyarrhythmias: - Ventricular tachycardia. Supraventricular tachycardia. Bradyarrhythmias: Third degree atrioventricular block. Transient hypotension or hypertension. Angina pectoris.

Others: Minor pharyngeal bleeding. Nausea and vomiting. Bacteremia


STRESS ECHOCARDIOGRAMIt is performed while the person exercises on a treadmill or stationary bicycle. To visualize the motion of the heart's walls and pumping action when the heart is stressed. It may reveal a lack of blood flow that isn't always apparent on other heart tests. The echocardiogram is performed just prior and just after the exercise.PRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE


NPO for four hours before the test.

Do not drink or eat caffeine products (cola, chocolate, coffee, tea) for 24 hours before the test.

Do not take any over-the-counter medications that contain caffeine for 24 hours before the test. PRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE

CONTDo not take the following heart medications for 24 hours before the test unless doctor tells .Beta-blockers (for example, Tenormin, Lopressor, Toprol, or Inderal)Isosorbide dinitrate (for example, Isordil, Sorbitrate)Isosorbide mononitrate (for example, Ismo, Indur, Monoket)Nitroglycerin (for example, Deponit, Nitrostat, Nitropatches)Do not discontinue any medication without talking with doctor.


Dobutamine stress echocardiogram A form of stress echocardiogram. Instead of exercising to stress the heart, the stress is obtained by giving a drug that stimulates the heart and makes it "think" it is exercising. The test is used to evaluate heart and valve function when unable to exercise on a treadmill or stationary bike. It is also used to determine how well heart tolerates activity and likelihood of having coronary artery disease, as well as evaluating the effectiveness of cardiac treatment plan.PRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE

Most dobutamine stress protocols start at an infusion rate of 5microgram/kg/mt and increase to a peak dose of 40 or 50 ug / kg / min To further increase heart rate, a bolus injection of 0.251 .0 mg atropine is addedPRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE


PREPARATIONWear comfortable clothing. Do not eat for a minimum of 4 hours before the test. Drinking water is allowed before the test. If diabetic, juice is allowed in the morning with insulin (1/2 dose). If on pills ,do not take medication until after the test is complete. Do not drink caffiene (coffee or tea) the day of the test. Stop taking all medications including beta blockers, calcium channel blockers, nitrates and digoxin for 24 hours prior to test


ECG electrodes will be placed to monitor electrocardiogram Blood pressure and ECG will be monitored throughout the test. Lie on left side on an exam table. An intravenous line (IV) will be inserted and dobutamine is administered . While the infusion of dobutamine is going on continous echo images will be taken. The medication will cause heart to react as if exercising. The dobutamine may give a warm, flushing feeling and some patients experience a mild headache. Report if there is chest pain, arm or jaw pain ,short of breath, dizzy or feel lightheaded. The IV line will be removed once all of the medication has entered bloodstream.


Intravascular ultrasound:A form of echocardiography performed during cardiac catheterization. During this procedure, the transducer is threaded into the heart blood vessels via a femoral catheterUsed to provide detailed information about the atherosclerosis (blockage) inside the blood vessels.PRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE

The Modalities of EchoThe following modalities of echo are used clinically:Conventional echo Two-Dimensional echo (2-D echo)Motion- mode echo (M-mode echo)

Doppler Echo Continuous wave (CW) DopplerPulsed wave (PW) DopplerColour flow(CF) Doppler

All modalities follow the same principle of ultrasoundDiffer in how reflected sound waves are collected and analysed


Two-Dimensional Echo (2-D echo)This technique is used to "see" the actual structures and motion of the heart structures at work.Ultrasound is transmitted along several scan lines(90-120), over a wide arc(about 900) and many times per second. The combination of reflected ultrasound signals builds up an image on the display screen.A 2-D echo view appears cone-shaped on the monitor.


M-Mode echocardiographyAn M- mode echocardiogram is not a "picture" of the heart, but rather a diagram that shows how the positions of its structures change during the course of the cardiac cycle. M-mode recordings permit measurement of cardiac dimensions and motion patterns.Also facilitate analysis of time relationships with other physiological variables such as ECG, and heart sounds.


(Time-motion mode)M-Mode gives an ice-pick view of the heart. The vertical axis gives the distance of each point from the transducer while horizontal axis gives the time period. M-Mode gives high resolution in the time axis so that it is easy to time various events in the cardiac cycle, especially if a syncronized ECG tracing is displayed along with it.


It is used for taking measurements of the left ventricle in systole and diastole to calculate the ejection fraction. The thickness of the interventricular septum (IVS)and left ventricular posterior wall (LVPW) are measured at this level. Asymmetric septal hypertrophy can be seen in hypertrophic cardiomyopathy. Septum can be thinned out in anterior wall mycoardial infarction, while the posterior wall will be thinned in inferoposterior infarction. Normally the septum moves with the left ventricle, meaning that it moves posteriorly in systole. Paradoxical anterior movement of septum in systole can be seen in atrial septal defect and other conditions of right ventricular volume overload. PRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE

Doppler echocardiographyDoppler echocardiography is a method for detecting the direction and velocity of moving blood within the heart. Pulsed Wave (PW) useful for low velocity flow e.g. MV flowContinuous Wave (CW) useful for high velocity flow e.g aortic stenosis Color Flow (CF) Different colors are used to designate the direction of blood flow. red is flow toward, and blue is flow away from the transducer with turbulent flow shown as a mosaic pattern.


PERICARDIAL EFFUSION


PLEURAL EFFUSION


LEFT VENTRICULAR CLOT


MITRAL REGURGITATION


AORTIC REGURGITATION


EJECTION FRACTION The volume of blood within a ventricle immediately before a contraction is known as the end-diastolic volume. The volume of blood left in a ventricle at the end of contraction is end-systolic volume. The difference between end-diastolic volume (EDV) and end-systolic volumes (ESV) is the stroke volume, the volume of blood ejected with each beat. Ejection fraction (Ef) is the fraction of the end-diastolic volume that is ejected with each beat; that is, it is stroke volume (SV) divided by end-diastolic volume (EDV)


CONT..In a healthy 70-kg (154-lb) man, the SV is approximately 70 ml and the left ventricular EDV is 120 ml, giving an ejection fraction of 70/120, or 0.58 (58%).

Healthy individuals typically have ejection fractions between 50% and 65%


Ejection fraction is commonly measured by echocardiography, in which the volumes of the heart's chambers are measured during the cardiac cycleIt is calculated as a ratio of Dimension between the ventricles in Systole and Diastole. For example, a ventricle in greatest dimension could measure 6cm while in least dimension 4cm. Measured and easily reproduced beat to beat for ten or more cycles, this ratio may represent a physiologically normal EF of 60%. Mathematical expression of this ratio can then be interpreted as the greater half as Cardiac Output and the lesser half as Cardiac input


THANK YOUPRASANTH.K, CARDIOTHORACIC NURSING, MSc, NARAYANA HRUDAYALAYA, BANGLORE

Health & Medicine

Echocardiogram Basics