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[definition term=”Cardiac Examination”]The physical exam is a very important part of the evaluation of all heart patients. A full physical examination is performed on your pet, with specific attention being placed on the organ systems that are affected by cardiac disease. The doctor will look at your pets eyes and ears and mouth. Special attention is given to the color of your pet’s gums as this can give us an idea of how much oxygen your pet is receiving and how hydrated your pet is. Feeling the skin will also give us an idea of hydration level as well as feeling the quality of your pets pulses. We typically feel the pulses of the femoral arteries, on the inside of the back legs, but we will also often look for pulses in your pets neck, called jugular pulses, as these may be present with certain types of heart disease. Your pets belly is felt, or palpated, for any discomfort and any fluid as sometimes the belly can become distended with fluid when heart disease is present.
Perhaps the most important aspect of the cardiac exam is when the doctor listens to your pet’s heart and lungs. This is called auscultation. The doctor uses a stethoscope, which amplifies sound, to listen for abnormal heart sounds such as heart murmurs, or gallop sounds or irregular heart rhythms. At the same time we are listening to the heart we will often feel the pulses to make sure all of the beats are matching. While listening with the stethoscope, we will also listen to the lung sounds. Sometimes abnormal sounds like crackles or increased or decreased lung sounds can indicate fluid in or around the lungs. Based on these examination findings we will then discuss if any further tests or treatments are recommended. [/definition]
[definition term=”Doppler blood pressure measurement”]Measuring blood pressure is a little different in cats and dogs than it is in people. Since their legs can be so small and furry, the typical methods used in people are not as accurate in pets. We use a small ultrasound crystal to amplify the sound of the pulse in the leg. A cuff, like the kind used in people, is placed on the leg and a small patch of fur is shaved behind the paw where the blood vessel is located. The crystal is placed over the blood vessel and we hear the pulse. The cuff is then inflated until the pulse can no longer be heard. We then slowly decrease the pressure in the cuff until we can hear the pulse again. The point at which this occurs is the systolic blood pressure measurement, which is equivalent to the top number measured in blood pressure in people. Normal blood pressure for cats and dogs is approximately 120mmHg, like people, but it may be as high as 160mmHg with stress.[/definition]
[definition term=”Thoracic radiographs”]One of the mainstays of diagnostics in cardiology is thoracic radiographs, or chest x-rays. Patients with heart disease often develop a cough for a number of reasons. The most concerning reason, because it can be life threatening, is the accumulation of fluid within the lungs, called congestive heart failure. Patients with heart disease can also cough, however, because of their enlarged heart pushing on their airways, or because they have concurrent lung disease. The best way to differentiate these causes of coughing is to take a radiograph. The radiographs permit us to look at the lungs to see if they are well expanded and full of air, or if there is any evidence of fluid present in the lungs.
Thoracic radiographs can also be useful for monitoring patients with a history of congestive heart failure who are not coughing. Once a patient has been diagnosed with heart failure, we typically recommended repeating radiographs every 3-4 months, because even if the pet is not coughing, we sometimes can detect smaller amounts of fluid in the lungs that indicate the need to adjust the patients’ medications. By detecting these abnormalities before they become a problem often avoids the need to hospitalize the patient since they are minimally symptomatic when it is detected.[/definition]
[definition term=”Echocardiography”]An echocardiogram is one of the main diagnostics used in cardiology. This is a sonogram, or ultrasound of the heart. It enables us to visualize the heart and all the chambers and major vessels to see if there may be a problem. We can assess the size and wall thickness of each chamber as well as how well the heart walls are contracting. We can also assess the flow of blood in the heart and look for any evidence of turbulence, holes in the heart or valve leaks. One of the biggest determinants of the risk of developing congestive heart failure, or fluid accumulation because of heart disease, is the size of the chambers of the heart. This is determined by the echocardiogram. This is the test that allows us to tell you specifically what is wrong with the heart and determine how serious your pet’s heart disease truly is. The test is performed just like a sonogram in a pregnant woman. Your pet has to lie on their side and we use alcohol and gel to make their fur wet and allow good contact for the ultrasound. The probe is placed on either side of the chest to assess the heart and obtain all of the images we need. The test is completely noninvasive and painless and patients are usually cooperative and do not require any type of sedative.[/definition]
[definition term=”Electrocardiography (ECG or EKG)”]An electrocardiogram, also called an ECG or an EKG, is a test that records the electrical activity of the heart to tell us if the patient has a normal or abnormal heart rhythm. This is helpful because some irregular heart rhythms can be very dangerous and require medications while other rhythms are not concerning and may not require medications. The only way to confirm an abnormal heart rhythm, however, is to perform the ECG.[/definition]
[definition term=”Holter Monitor Recording”]A Holter monitor is an extended version of an electrocardiogram. Five small electrodes are attached to your dogs skin (some fur does need to be shaved). These electrodes are secured with a small amount of tape and a vest and the monitor is worn for 24 hours. The monitor records the patient’s heart rate and rhythm during all of the normal daily activities. Your pet is brought back to the hospital 24 hours later, and the Holter is removed and analyzed. The doctor will call you within the next several days with the results of this test.[/definition]
[definition term=”Event Monitor Recording”]An event monitor is similar to a Holter monitor in that it is a vest that your pet wears to record the heart rhythm. In contrast though, it continuously records the heart rate and rhythm in a loop for as many days as necessary. If your dog has an event, such as a fainting or weakness spell, you press a button and it saves the rhythm for a period of time before, during and after when the button is pressed. This test helps us to determine the cause of fainting spells.[/definition]
[definition term=”Telemetry Monitoring”]Telemetry monitoring, like a Holter monitor, is a continuous ECG recording of the patients heart rate and rhythm. This test is used in hospitalized patients and enables us to watch their heart rhythm on a computer screen while they are in the critical care unit.[/definition]
[definition term=”Diagnostic Angiography”]Diagnostic angiography is a test that is not commonly needed, but in certain congenital diseases or vascular abnormalities it may be important to figure out if there is an abnormal flow of blood through the body. A special type of dye, called a contrast agent, is injected into a vessel in the leg or in the neck. The path of contrast through the vessels and the heart is then watched and recorded on a continuous x-ray. By watching the flow of contrast over time, we can determine if there are abnormal vessels or abnormal communications between vessels.[/definition]
[definition term=”Balloon valvuloplasty for valvular stenosis”]On of the more common heart problems animals can be born with is narrowing, or stenosis, of a heart valve. This abnormality can be corrected in many patients with a procedure called balloon valvuloplasty. This is a minimally invasive surgery that is done entirely through a small incision made over a vessel. This is most commonly performed through an incision in the neck where we can access the jugular vein. Catheters are passed from the jugular vein and into the heart where the pressures within the heart are measured. Once these measurements are obtained a dye study, or angiogram, is then performed to assess the abnormal valve and the structure of the remainder of the heart. A long, narrow catheter with a high strength balloon on the end is then passed into the center of the abnormal valve. This balloon is inflated and, if successful, the valve will tear open and become less narrow. This will allow better flow of blood through the valve and can lead to improve quality of life and, potentially, a longer life for patients born with this disease.[/definition]
[definition term=”Device placement for occlusion of patent ductus arteriosus (PDA)”]One of the most common congenital diseases in dogs is a patent ductus arterious or PDA. The ductus arteriosus is a vessel that is normally present in a fetus before birth that allows blood to bypass the lungs since they are not needed yet. When a puppy is born, this vessel normally closes so that blood then flows to the lungs. If this vessel fails to close completely, the blood continues to flow abnormally, overwhelming the heart and eventually causing the heart to become enlarged. If severe enough this can result in congestive heart failure (fluid in the lungs). Depending on the severity, this disease can drastically shorten a dog’s lifespan.
There is a special device, call an Amplatz Canine Ductal Occluder (ACDO) that can be used to close this abnormal vessel and cure the disease, allowing the dog to lead a normal lifespan. The surgery is minimally invasive and involves only a small incision on the inside of the back leg. A catheter is passed into a vessel in the leg and up into the heart. The catheter is passed through the abnormal vessel and pressures are measured inside these vessels. A special dye is then injected to assess the PDA and look for any other abnormalites that could not be seen on the echocardiogram. Following the dye study the device is then secured into place in the abnormal vessel, occluding the blood flow in that vessel. The dye study and pressure measurements are then repeated. Once the closure of the vessel is confirmed, the catheter is removed and the incision is sutured closed.[/definition]
[definition term=”Pacemaker placement and maintenance”]Cats and dogs, like people, can develop abnormally slow heart rhythms causing them to feel weak or faint. Implantation of a cardiac pacemaker can fix these symptoms, allowing pets to have a normal heart rate again and eliminate these episodes.
There are two ways a pacemaker can be implanted. For very small dogs and cats, it is best to place a pacemaker through traditional surgery. An incision is made into the abdomen and the surgeon goes through the diaphragm to access the heart. The pacemaker leads are attached to the outside of the heart and the pacemaker generator (the battery and computer part) is secured in a pocket in the side of the belly. The incision is then closed with sutures and appears much like a spay incision.
In most other patients a pacemaker is placed with a minimally invasive surgery. A small incision is made over the jugular vein in the neck and the pacemaker lead wire is placed in the jugular vein and fed into the heart with the guidance of a continuous x-ray machine called a fluoroscopy unit. Once the pacemaker lead is in the proper position it is attached to the heart muscle and the generator is attached to the other end of the lead. Once the generator is attached it begins beating for the patient so that the patient then has a normal heart rhythm. The generator is usually sutured into place just in front of the shoulder. The incision is closed with sutures and the patient is awaken from anesthesia.
Following the procedure, the patient needs to have the pacemaker checked, or interrogated, every 6 months. This allows us to determine how much of the battery life is remaining on the pacemaker and to see if the pacemaker is functioning properly. At these visits, small adjustments can be made by placing a magnet over the pacemaker generator and reprogramming the generator. This does not involve any wires or surgery and is completely painless, as everything is done using a magnetic field.[/definition]
[definition term=”Tracheal stent placement for collapsing trachea”]Some dogs, particularly small breed dogs such as Pomeranians and Yorkshire terriers, suffer from a weakened windpipe, or trachea. As they age, the tracheal cartilage in the neck becomes weaker and the trachea collapses with any type of excitement or heavy breathing. This can cause severe respiratory distress that can be life threatening.
With the patients who are mildly to moderately affected, it is best to try medications to treat this condition. In patients with very severe collapsing tracheas though, medications may not be enough. In these cases we can implant a tracheal stent. A stent is a flexible, tubular structure woven from metal thread. The stent, when placed, holds the trachea open, preventing collapse.
We first watch the animal under a continuous x-ray machine, or fluoroscopy unit, to make sure this is truly what’s occurring and measure the dimensions of the airway. Once these measurements are obtained we anesthetize the patient, and using the guidance of fluoroscopy, advance the specialized expandable stent into the trachea. Once we are in the correct location within the trachea, we slowly release the stent until it is secured in the trachea. Once secured the stent cannot be removed and it is fixed into place. This helps keep the trachea from collapsing, and greatly improves the pet’s ability to breathe.
Most patients will still require medications for the rest of their life, but this procedure can limit the severity of signs seen with the disease and often minimize the amount of medication needed.[/definition]
[definition term=”Electroconversion of atrial fibrillation”]Some patients suffer from an irregular heart rhythm called atrial fibrillation. This abnormal rhythm can make the heart beat very fast. In many of these patients, medications can be used to keep the heart rate down, enabling them to feel better despite the irregular rhythm, but in some patients this is not possible or practical.
In these patients the best mode of treatment can be to convert the irregular rhythm back to a normal rhythm. This can sometimes be done with medications, but the medications can have significant side effects. Another effective means of converting the abnormal rhythm is to use electroconversion. While this method sounds scary, it is considered just as safe as medications, and is associated with less side effects.
Electroconversion is done using a specialized defibrillator called a biphasic, synchronized defibrillator. This enables us to have the machine detect the patients own heart beats so that a shock can be delivered safely. The machine also delivers smaller bursts of electrical energy, allowing us to get away with less stress on the heart compared to older machines.
For the procedure, the animal is anesthetized and placed on its back in a soft trough. The sides of the chest are shaved to get good contact with the defibrillator paddles and the machine is synchronized to the patients heart beats while watching the heart rhythm on a electrocardiogram (ecg or rhythm strip). The shock is then quickly delivered and the heart rhythm is watched for conversion to a normal rhythm. If this is not successful, the amount of energy used is increased and the procedure is repeated. Once the patient has been successfully converted, they are then awakened from anesthesia and the heart rate and rhythm are monitored on a continuous ecg in the critical care unit until they are ready to go home.[/definition]
[definition term=”Thoracoscopic Pericardectomy”]Some animals suffer from an accumulation of fluid in the sac around the heart, called pericardial effusion. This may be caused by a tumor on the heart, or sometimes an underlying cause is not determined. If this fluid accumulates quickly, it can cause the heart to collapse and can cause fainting episodes or even sudden death.
To limit the risk associated with the fluid accumulation, and in some cases cure pericardial effusion, we can surgically remove the pericardium, the layer around the heart. This can be done through traditional surgery through the chest, or may be done as a minimally invasive procedure using cameras. This is called thoracoscopic pericardectomy.
This technique is performed by a board certified surgeon. It involves making four small incisions at separate areas along the chest for sites to insert the camera, instruments and suction. Once the pericardium is removed it is then submitted for a biopsy, where the tissue is looked at under a microscope. This may help us determine an underlying cause of the fluid accumulation.[/definition]
[definition term=”Thoracocentesis and Abdominocentesis”]Patients with heart disease can often accumulate fluid in the space around the lungs or in the abdomen. This is called congestive heart failure. When this occurs, we can remove fluid from these spaces with a needle. This enables the patient to breathe easier and feel more comfortable, limiting the clinical signs seen because of the fluid.[/definition]
[definition term=”Catheter retrieval of heartworms”]Though not common in this area, we do see pets who are infected with heartworms. In patients that are severelyaffected, a heavy worm burden can lead to dysfunction of the heart, allowing fluid to accumulate in the chest or the belly. These patients are at a high risk for a reaction to the injectable medication used to kill the heartworms. To decrease the risk some dogs need to have most of the worms removed before they can be treated. Removing the worms will also allow the heart function to improve, stopping the fluid from building up in the body.
The patient is anesthetized and a small incision is made over the jugular vein in the neck. The heart is monitored with continuous x-ray, or fluoroscopy, to guide us during the procedure. A specialized snare is passed into the jugular vein and down into the heart. Once it is in the correct location, the snare is used to grab the worms and pull them back out through the jugular vein. Once sufficient worms are removed the patient is awakend from anesthesia and monitored closely to make sure there is no allergic reaction to the worms. They are then placed on heartworm preventative for 2 months prior to receiving the injections that kill any remaining heartworms.[/definition]