Ultrasonography, a image technique to evaluate soft tissue using high frequency sonorous waves, represents one of the most dramatically advances in the practice of veterinarian clinic. A number of studies made in dogs and cats established its use for quantitative and qualitative evaluation of the cardiac function
The echocardiography allows a safe and not invasive evaluation of the cardiac patient with a minimum stress. In situations of high risk the echocardiography can be used to measure the size of the heart, to supply tomographic images in real time and with the use of the doppler to evaluate the physiological condition of the heart. It has two modalities of echocardiography. The M way supplies graphical images of some cardiac structures. The result is an image of difficult reading, and anatomically not familiar! However, it allows the characterization of subtler anomalies from the movement, especially valves (aortic and mitral). The bidimensional way (2DE), also effected with sectorial sweepings, supplies images of the different cardiac plans. This allows a tomographic bidimensional vision (in cuts) and anatomically familiar. The physician is informed about cardiac space anatomy and its function in a not invasive form. As much a symmetrical increase how much anti-symmetrical are recognized, the soft tissue can be distinguished from the liquid, thus, vegetations and neoplasics formations can be seen. The cardiac movement in relation to extra-cardiopaths structures can be observed and be quantified
The authors use the echocardiography mainly to evaluate patients with suspicion of cardiomegaly detected by electrocardiography or thoracic x-ray, and to evaluate patient with murmur or questionable sounds to the auscultation. The echocardiography supplies an anatomical description of the disease, and it can identify the progression of heart dysfunction. The left ventricular (LV) function is quantifiable without the need of invasives studies. Dogs with mitral insufficiency are appraised to determine the integrity of the strings, the extension of the valve damage and the size of the left atrial chamber. Dogs with congestive cardiomiopathy can have the left ventricular function quantified by fraction of certain shorten by echographical exam. In the cat, the echocardiogram is used to differentiate among congestive and hypertrophical cardiomiopathies (extensive). The ultrasonographical study allows to measure repeated times of heart indexes in animals with systemic hypertension and hyperthyroidism.
The echocardiography can also be used to control the effects of therapeutic interventions and effects of another diseases in the heart. Pericardial effusion, pericardial masses and heart tumors (VE,AE,AD or base of the heart more commonly) and perforating strange bodies are quickly identified by bidimensional way. Pleural effusions, pleura, lungs and masses mediastinals and diaphragmatic hernias are regularly identified. Ultrasound is also extremely useful in the diagnosis of congenital heart diseases, once it supplies specific anatomical description and fundamental details for the diagnosis. The shunts right to left can be identified for the use of a saline or green solution of indocyanin that form bubbles elucidating the anatomical defect. The definitive diagnosis of a congenital lesion can request the use of the Doppler.
In dogs and cats, the left side of the heart is seen better than the right, due to proximity on the right side with the transducer and the difficulty to adjust the echoes in the closer field. The right structures are observed better when there is fluid between the transducer and these, on the right side of the heart. In lineal studies it is indicated, as well as in the area measures the correlation with corporal size (animal size). The most left ventricular function is independent of the corporal weight in dogs, but JACOBS & KNIGHT suggest that variations in the weight can affect other indexes and they can in the feedback to affect the left ventricular function in the cat. The dimensions as well as the measures of the windows right and left are almost identical
INDICATIONS TO EXECUTE ECHOCARDIOGRAPHY
- Patients' evaluation with suspicion of cardiopathy;
- To identify the cardiomegaly cause detected in the electrocardiogram or x-ray, differentiating the hypertrophy dilation;
- To evaluate patient with questionable sounds in the cardiopulmonary auscultation;
- To identify the progression of the heart effusions and its therapy;
- To evaluate the left ventricular function in a quantitative way and measurement;
- To identify pericardial effusions, pleura, pericardial masses and heart tumors and perforating strange bodies; l
- Lung, mediastinal masses and diaphragmatic hernias;
- Congenital heart diseases
