Heart examination in dogs and cats

How is a heart examination carried out?

A cardiac evaluation starts with a medical history and a clinical examination. The veterinarian listens to the heart and lungs, assesses the heart rhythm, pulse and other findings that may be relevant. Further examinations are selected based on what we find and what symptoms the animal has.

An examination may include, among other things, echocardiography with Doppler and ECG, regular ECG, Holter ECG, digital X-ray of the heart and lungs, measurement of heart size, blood pressure measurement and blood tests. It is not necessary for all patients to undergo all the examinations.

Ultrasound of the heart – echocardiography

Echocardiography is an ultrasound examination of the heart. At A-Vet we use an Esaote MyLab X9 with color Doppler, spectral Doppler and ECG for cardiac examinations. The ECG signal can be recorded simultaneously with the ultrasound examination and makes it possible to link Doppler signals and measurements to the different phases of the cardiac cycle.

With ultrasound, we can examine the heart's chambers, wall thickness, valves, and the large blood vessels near the heart. We can also assess how the heart muscle contracts and fills, and with Doppler, examine the direction and speed of blood flow through the heart.

Echocardiography is used to diagnose valvular disease, cardiomyopathies, and congenital heart defects. The examination can also reveal fluid in the pericardium, changes in the size of the heart, and other structural abnormalities.

Cardiac ultrasound is usually performed while the animal is awake. If a dog or cat is very scared or stressed, sedative medication may be necessary in some cases. This is considered on an individual basis because sedation can also affect some physiological and echocardiographic measurements. You can read more about calming and sedation in dogs and cats.

ECG

An electrocardiogram (ECG) records the electrical activity of the heart and is primarily used to examine the heart rhythm. An ECG may be necessary if the veterinarian hears an irregular rhythm, or if the animal has had episodes of fainting, collapse, or unexplained weakness.

During echocardiography, we can record the ECG simultaneously on the Esaote MyLab X9. This makes it possible to see the electrical heart rhythm simultaneously with the ultrasound and Doppler examination.

For targeted examination of the heart rhythm, we also use the IDEXX CardioPet ECG. The system records six ECG leads simultaneously and is widely used in our cardiac evaluation. If necessary, ECG recordings can also be sent to a veterinary cardiologist through IDEXX VetMedStat for external specialist evaluation.

If necessary, we also send ultrasound clips from the echocardiography for external specialist evaluation via IDEXX VetMedStat. This may be relevant when we want a supplementary cardiological evaluation of the ultrasound findings.

If necessary, we send ultrasound clips from the echocardiography for external specialist evaluation via IDEXX VetMedStat. This may be relevant when we want a supplementary cardiological evaluation of the ultrasound findings.

Holter ECG and long-term recording

Some rhythm disturbances only occur intermittently and are therefore not necessarily captured on a short ECG at the clinic. In these cases, we can use our Televet 100 system for long-term recording of the heart rhythm.

Holter ECG records the heart rhythm continuously over a long period of time while the dog is at home and performing normal activities. This makes it easier to detect rhythm disturbances that occur sporadically or in connection with activity, rest or sleep.

The equipment is installed at the clinic, and the owner simultaneously keeps track of activity and any symptoms. The recording is then evaluated together with the activity log to investigate which rhythm disturbances occur, how often they occur and whether they coincide with symptoms.

X-ray of the heart and lungs

Chest X-rays are an important part of the cardiac evaluation for some patients. At A-Vet, we take digital X-rays of the heart and lungs and assess, among other things, the size and shape of the heart silhouette, the pulmonary vessels, the lung fields and the area around the lungs.

On the X-rays we can also assess and measure the size of the heart. If necessary, we use standardized measurements such as vertebral heart size (VHS) and vertebral left atrial size (VLAS). The measurements are interpreted together with the animal's species, breed, body structure, X-ray projection and other findings, because the normal size and shape of the heart silhouette varies between different animals.

In heart failure, an X-ray can show changes in the pulmonary vessels and fluid in the lungs – pulmonary edema. In cats, heart failure can also lead to fluid in the chest cavity, so-called pleural effusion. An X-ray is therefore particularly useful when we are investigating whether breathing difficulties or coughing may be related to heart disease, or whether the findings rather point to disease in the airways or other structures in the chest.

X-rays and echocardiography complement each other. X-rays provide a good overview of the heart, lungs and chest cavity, while echocardiography provides far more detailed information about the heart's chambers, valves, wall thickness, blood flow and function.

Blood pressure measurement and blood tests

Blood pressure can be an important part of the cardiac evaluation, especially in cats. Systemic high blood pressure can affect the heart and can lead to thickening of the left ventricle, among other things.

If necessary, we also take blood tests to investigate diseases that may affect the heart or have implications for further treatment. In older cats with heart changes, for example, it may be relevant to examine the metabolism, because high metabolism can cause heart changes that must be included in the assessment.

Example of an extended cardiac examination

Some heart patients require more extensive follow-up than others. One of our canine patients with known valvular heart disease also developed periodic arrhythmias. In this case, echocardiography, ECG, chest x-ray, blood pressure measurement, and repeated check-ups were used together to monitor development over time.

The ECG showed atrial extra beats and brief episodes of rapid heart rate, among other things. X-rays were used to assess and measure the size of the heart and check the lungs for signs of heart failure, while echocardiography provided detailed information about the valves, chambers of the heart, and blood flow.

In this more complex course, ECG recordings from several check-ups were also sent to a veterinary cardiologist through IDEXX VetMedStat for external specialist assessment. Because some rhythm disturbances only occur sporadically, long-term recording with Holter ECG may also be appropriate in such cases.

This is an example of a more complex process. Many dogs and cats who come for a cardiac evaluation need far fewer tests, and which tests are appropriate are assessed individually.

Cardiac expertise at A-Vet

Veterinarian Magda works particularly with heart diseases and cardiac evaluations at A-Vet and follows many of the clinic's cardiac patients. She performs, among other things, echocardiography with Esaote MyLab X9, ECG with IDEXX CardioPet ECG and long-term recording with Televet 100.

Magda is undergoing further training in small animal cardiology and will take the General Practitioner Certificate in Cardiology (GPCert in Cardiology) exam through the International School of Veterinary Postgraduate Studies (ISVPS) in October 2026.