Cardiology

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Our board-certified cardiologist can examine breeding and show pets for congenital heart disease. Cardiac evaluation procedures include Holter monitoring, pacemaker implantation, balloon valvuloplasties, ECG, cardiac ultrasound and specialized management of dogs and cats with heart disease (eg. PDA in dogs).

Auscultation:

Anomalies discovered when auscultating the heart may be the first clue of heart disease. These anomalies include heart murmur, extra heart sounds, and irregular heart rhythm.

We use a scale of 6 grades to describe the loudness of a heart murmur. The loudness of the murmur is crudely correlated to the severity of the heart disease. Most of the dogs with heart disease have a heart murmur.
Heart murmurs in cats with heart disease are not always present, and detection of heart disease before major symptoms may be difficult.

Thoracic radiography:

Thoracic radiography helps us determine the overall heart size and shape, as well as allowing us to evaluate the lungs and the presence or fluid in or around the lungs (heart failure).

Electrocardiography:

Electrocardiography is helpful to evaluate the heart rhythm. It is recommended when we auscultate an irregular heart rate (arrhythmia), or when symptoms such as fainting are present. Regular electrocardiogram (ECG): This type of ECG provides a 2-3 minutes recording of the heart rhythm. It can be helpful if the arrhythmia is heard during auscultation.

24hr ECH recording (Holter): Sometimes, arrhythmias can be intermittent and may not be detected by a spot ECG. This is where a 24 hr ECG recording using a Holter can provide better information (24 hr of information versus 2-3 minutes). Holters are also helpful to document efficacy of medications prescribed to regulate the heart rhythm (antiarrhythmics). Holters are often used in breeds prone to develop arrhythmias such as Boxers and Dobermans, for screening purposes.

Echocardiography with Doppler assessment:

Doppler-echocardiography (cardiac ultrasound) is one of the most important procedures to evaluate the heart. This technique allows visualization of the inside of the heart. Doppler-echocardiography will provide information on cardiac walls thicknesses, inner cavity dimensions, cardiac function (contractility and relaxation), valve competence (normal opening and closing, inability to open properly (stenosis), and inability to close properly (regurgitation)). Echocardiography is also very helpful to diagnose fluid accumulation in the sac around the heart (pericardial effusion), and in the chest (pleural effusion).

Blood pressure assessment:

Blood pressure assessment is a standard part of the cardiac evaluation. It helps us better evaluate the severity of the situation, the appropriate treatment to give, and the response to medications that affect blood pressure (vasodilators), frequently used in cardiology.

Ancillary testing:

Plasma taurine level: Taurine is a protein that is essential to the good function of the heart. Some dogs may develop a taurine deficiency, which may lead to a dysfunction of the heart (characterized by a weak contraction). If the taurine deficiency is corrected by adequate dietary supplementation, then the weakness of the heart can be corrected. Taurine deficiency can be readily documented by measuring plasma taurine levels. Taurine deficiencies have been documented in Cockers and Newfoundland, as well as many other breeds of dogs. It used to be common in cats, before taurine levels were readjusted in cat diets. It is now very rare.

Congenital Cardiac Disease and the OFA:

Congenital heart diseases in dogs are malformations of the heart or great vessels. The lesions characterizing congenital heart defects are present at birth and may develop more fully during perinatal and growth periods. Many congenital heart defects are thought to be genetically transmitted from parents to offspring; however, the exact modes of inheritance have not been precisely determined for all cardiovascular malformations.

Developmental Inherited Cardiac Diseases (SAS and Cardiomyopathy):

At this time inherited, developmental cardiac diseases like subaortic stenosis and cardiomyopathies are difficult to monitor since there is no clear cut distinction between normal and abnormal. The OFA will modify the congenital cardiac database when a proven diagnostic modality and normal parameters by breed are established. However at this time, the OFA cardiac database should not be considered as a screening tool for these diseases.

Purpose of the OFA Cardiac Database:

To gather data regarding congenital heart diseases in dogs and to identify dogs which are phenotypically normal prior to use in a breeding program. For the purposes of the database, a phenotypically normal dog is defined as:

1.   One without a cardiac murmur -or-
2.   One with an innocent heart murmur that is found to be otherwise normal by virtue of an echocardiographic examination which includes Doppler echocardiography