Echocardiogram in Dogs (Cardiac Ultrasound)
An ultrasound (echocardiogram) is a non-invasive procedure used to evaluate the internal organs. Ultrasound examinations can be used to examine the heart, abdominal organs, eyes and reproductive organs. Ultrasound applied to the heart is called an "echocardiogram".
For many problems, both ultrasound and X-rays are recommended for optimal evaluation. The X-ray shows the size, shape and position of the heart and chest contents, and also permits the veterinarian to examine the lungs. In contrast, the echocardiogram cannot be used to examine the lungs, but this ultrasound exam allows the veterinarian to see inside the heart. For moving organs such as the heart, the size, tissue character, and muscle function can be assessed in what is called a "real time" examination that resembles a motion picture. Components of the echocardiogram can include the two-dimensional exam (to see lesions and overall cardiac structure), the M-mode study (used to measure heart size and function), and the Doppler examination (used to evaluate blood flow). These examinations are complementary.
An echocardiogram is indicated to evaluate pets with a suspicion of congenital or acquired heart disease. An echocardiogram may be performed when indicated by the results of an X-ray, when there is a suspicion of heart disease based on physical examination. For example, detection of a heart murmur or irregular heart rhythm could be an indication for an echocardiogram.
Many veterinarians refer animals needing an echocardiogram to a specialist because performing the procedure requires particular skills and equipment. Some clinics do have ultrasound facilities on-site, while others use the services of mobile specialists who come to the clinic to perform echocardiograms. There is no real contraindication to performing this test. Even normal results help determine health or exclude certain diseases.
What Does an Echocardiogram Reveal?
Echocardiograms help to evaluate the structure and function of the heart. This test can be extremely useful for identifying birth defects, diseases of the heart valves, and heart muscle diseases (cardiomyopathy). The exam also can be used to identify fluid around the heart (pericardial effusion), cardiac tumors, and certain types of heartworm infections. The chest cavity and cranial mediastinum (upper chest cavity) also can be evaluated, though in most cases the lungs cannot be visualized (due to the air in this organ).
How Is an Echocardiogram Done?
Specialized (and very expensive) equipment is required to perform an ultrasound exam. The hair on the chest may need to be clipped. The pet is placed on his side on a padded table and held so the chest surface over the heart is exposed to the examiner. A conductive gel is placed on a probe (transducer) that is attached to the ultrasound machine. The examiner places the probe on the skin between the ribs and moves it across the surface to examine the heart from different perspectives. Ultrasound waves are transmitted from the probe and are either absorbed or echo back from the heart structures. Based on how many sound waves are absorbed or reflected, an image of the heart is displayed on a computer screen. With proper training and sufficient experience, the sonographer (examiner) can create consistent images of the heart to create a three dimensional reconstruction of this organ and recognize departures from normal. Echocardiography is a safe procedure and generally takes about 30 to 60 minutes to complete. Additional time is spent measuring heart values.
Is an Echocardiogram Painful?
No pain is involved. The procedure is noninvasive.
Is Sedation or Anesthesia Needed for an Echocardiogram?
Neither sedation nor anesthesia is needed in most patients; however, some pets resent laying on their sides, and may require some sedation to allow a diagnostic procedure. Sedation also can be advisable if there is difficulty in breathing due to heart or lung disease to reduce any stress associated with an unfamiliar procedure.