Veterinarians use a stethoscope to listen to the heart. You can listen to your dog’s heart by placing your ear against his chest. The normal heartbeat is divided into two sounds. The first is a lub,followed by a slight pause and then a dub. Put together, the sound is lub-dub, lub-dub . . . in a steady, evenly spaced rhythm.
The heartbeat should be strong, steady, and regular. A slight alteration in rhythm as the dog breathes in and out is normal. An exceedingly fast pulse can indicate anxiety, fever, anemia, blood loss, dehydration, shock, infection, heat stroke, or heart (and lung) disease. A slow pulse can indicate heart disease, pressure on the brain, or an advanced morbid condition causing collapse of the circulation.
An erratic, irregular or disordered pulse indicates a cardiac arrhythmia. Many arrhythmias are associated with a sudden drop in blood pressure as the arrhythmia begins. The corresponding decrease in blood flow to the muscles and brain is accompanied by sudden weakness or collapse, often giving the impression of a fainting spell.
When the heart sounds can be heard all over the chest, the heart is probably enlarged.
Heart murmurs are common. Murmurs are caused by turbulence in the flow of blood through the heart. Serious murmurs are caused by heart disease or anatomical defects.. Anemia can cause a heart murmur.
Not all murmurs are serious. Some are said to be innocent; that is, there is no disease, just a normal degree of turbulence. To determine whether a murmur is serious or innocent, your veterinarian may request diagnostic studies such as a chest X-ray, an electrocardiogram (ECG or EKG), and an echocardiogram.
Thrills are caused by turbulence of such a degree that you can feel a buzzing or vibration over the chest. This suggests an obstruction to the flow of blood-for example, a constricted valve or a hole in the wall between two chambers of the heart. A thrill indicates a serious heart condition.
The pulse, a transmitted heartbeat, is easily detected by feeling the femoral artery, located in the groin. With your dog standing, or preferably lying on his back, feel along the inside of the thigh where the leg joins the body. Press with your fingers until you locate the pulse.