Ventricular Premature Complex in Cats

Ventricular Premature Complex in Cats

Ventricular premature complexes may be due to numerous etiologies, which includes; cardiac disease, pericardial effusion, metabolic disease and electrolyte disturbances, tickborne disease, fever, pain, anemia, altered autonomic tone, trauma, sepsis, DIC, splenic disease, hepatic disease, gastrointestinal disease, and pheochromocytoma.  

Additional diagnostics with these general differentials may be indicated based on this patient’s clinical presentation and examination.

Atrial Premature Complex in Cats

Atrial Premature Complex in Cats

Atrial premature complexes are often the result of atrial dilation (left or right); however, additional considerations would be mechanical irritation (perihilar lymph node enlargement, atrial/auricular mass, heart base tumor, pericardial disease, etc.), infectious/tick-borne disease, metabolic disturbances, or potentially altered autonomic tone (sympathetic/parasympathetic imbalance).  

This rhythm is fortunately not considered fatal in itself.  If atrial dilation is the underlying etiology, your pet may go into atrial fibrillation in the future.

Antiarrhythmic therapy may be indicated based on the frequency and grade of atrial arrhythmias noted on the ECG.

Atrial Fibrilation in Cats

Atrial Fibrilation in Cats

Atrial fibrillation is a condition where the atrium (top chambers of the heart) are no longer allowing organized electrical activity.  

Rather, there is a random oscillation of electrical waves that do not allow the atrium to contract as they should.  

The Atrioventricular Node (AV Node) responds to this haphazard electrical activity in a very irregular and rapid pattern, causing a very irregular, rapid heart (pulse or ventricular response) rate.

This condition is typically the result of severely dilated chambers.  This condition can rarely be corrected; however, the ventricular response rate can be lowered to a reasonable level with medications, frequently the combination of Digoxin and Diltiazem.

Continued rechecks and monitoring for adequate heart rate control are essential to ensure these patients remain at an optimal heart rate and do not develop congestive heart failure (fluid in the lungs).

Ventricular Spetal Defect (VSD) in Cats

Ventricular Spetal Defect (VSD) in Cats

A Ventricular Septal Defect (VSD) is a congenital cardiac disease, causing communication between the left and right ventricle.  

These can occur in numerous locations and the changes to be expected depends on the exact location.  

The development of left-sided (most common in veterinary medicine) or right-sided congestive heart failure is possible.  

Based on the precise findings, we will discuss appropriate management options.  

Some cases require monitoring, others medical management, and some surgical intervention

Congenital Mitral Valve Dysplasia in Cats

Congenital Mitral Valve Dysplasia in Cats

Congenital Mitral Valve Dysplasia is a condition where the mitral valve (separating the left atrium and left ventricle) did not form correctly at birth.  As a result, the valve does not close (coapt) normally.

This poor coaptation allows reverse blood flow (left ventricle into left atrium), which is termed regurgitation or insufficiency.  

This disease is progressive in that the chambers will continue to dilate, but the valve structure likely will not change.  

Routine rechecks are required to monitor for any changes to the left atrium or ventricle that may warrant additional testing or direct medical management of this disease.  

Eventually, this disease can lead to the development of congestive heart failure (fluid in the lungs), which is a medical emergency that makes breathing very difficult.

Reverse Patent Ductus Arteriosus (rPDA) in Cats

Reverse Patent Ductus Arteriosus (rPDA) in Cats

A right to left Patent Ductus Arteriosus (Reversed PDA or rPDA) is a congenital defect where the ductus arteriosus (fetal vascular connection) remains present after birth.  

The pulmonary pressures rise dramatically due to a problem within the lungs (Eisenmenger’s Physiology), causing blood to flow from the main pulmonary artery into the descending aorta.  

This high concentration of deoxygenated blood causes a high degree of deoxygenated blood to flow to the back half of the body, particularly the kidneys.  

This is seen clinically as differential cyanosis (blue/purple caudal membranes, pink cranial membranes).  A rPDA results in severe elevations of the hematocrit (PCV or HCT) as the kidneys respond to the deoxygenated blood by signaling for more red blood cell production.  

Affected patients will typically become neurologic (seizures, altered mentation, weakness, collapse, inappetance, or trembling) as the hematocrit rises.  

These patients are also at risk for sudden death due to arrhythmias, neurologic conditions (embolic events or seizures), or potentially right-sided congestive heart failure.

There is no cure for this condition.  

Therapy is directed towards lowering the pulmonary pressures, thus reducing the degree of shunting and therapeutic phlebotomy (blood draws) as necessary to maintain the hematocrit around 60-65%.  

The prognosis is typically poor; however, some patients will live for many years with optimal medical management.

Patent Ductus Arteriosus (PDA) in Cats

Patent Ductus Arteriosus (PDA) in Cats

A Patent Ductus Arteriosus (PDA) is a congenital defect where the ductus arteriosus (fetal vascular connection) remains patent after birth.  

This allows blood to flow from the aorta into the main pulmonary artery.  

If left untreated, this allows severe fluid overload to the left side of the heart.  

This causes severe left atrial and left ventricular dilation, eventually resulting in left-sided congestive  heart failure (fluid on the lungs).  

Affected patients will typically progress into congestive heart failure by 1 year of age and most patients will die by 3 years of age.  

It is important to monitor these patients for the development of congestive heart failure as medications are required to control this condition and maximize life expectancy and quality of life.  Fortunately, with surgical correction, the life expectancy of patients with this condition is generally normal (unless advanced myocardial insult has happened before diagnosis).  

he surgical procedure typically recommended is a transvenous occlusion, but the size of your pet may impact surgical options.  

This is a minimally invasive surgery that is performed through a small incision in the rear limb.  

The catheter is passed across the PDA from the femoral artery and a device (coil, plug, or occluder) is placed within the PDA.  

This allows a blot clot to form that is eventually replaced with fibrous tissue, resulting in a permanent occlusion.

Physiologic Murmur in Cats

Physiologic Murmur in Cats

A physiologic murmur is quite common in cats.  

This is usually the result of a dynamic right ventricular outflow tract obstruction (dRVO).  

This condition is created when the muscle of the right ventricular outflow tract squeezes and narrows the exit to the right ventricle.  

Much like a garden hose with your thumb over the end, this creates fast and turbulent blood flow, which is noted as a murmur.  

This finding has been well-studied in cats and is not linked to any advserse clinical outcomes, concerns, or problems.  

The primary worry is that it limits our accuracy of auscultation in monitoring for adult-onset disease. 

No treatments or medications are required.

Pulmonary Arterial Hypertension in Cats

Pulmonary Arterial Hypertension in Cats

Pulmonary arterial hypertension is a state of high blood pressure within the lung (pulmonary) circulation.  

This condition can be due to heartworm disease and embolic disease (clots into the lungs); however, some cases are considered idiopathic (cause unknown).  

Many cases may also develop pulmonary arterial hypertension due to chronic airway disease (pulmonary fibrosis, cancer, or pneumonia).  

This disease process involves damage to the pulmonary arteries and thickening/constriction of these vessels, increasing resistance to flow.  

Medications are utilized to reduce the pulmonary arterial pressures and improve quality of life.  

No medications can return these pressures to normal; however, many patients display a significant improvement in their quality of life.

Systemic Hypertension in Cats

Systemic Hypertension in Cats

Systemic Hypertension is a state of high blood pressure within the body.  

This means that the heart must work very hard to propel blood forward, which increases oxygen demands and can cause changes to the myocytes (muscle cells).  

In veterinary medicine, this condition is typically a result of chronic kidney disease, thyroid disease, or various other metabolic conditions.  

In some cases, essential (idiopathic) hypertension may be suspected.  This condition can cause severe end-organ damage to include the brain, heart, kidneys, and eyes.

If an underlying condition can be identified, treatment is directed towards that condition and maintaining the systemic blood pressure at a reasonable level with medications.

 Frequent rechecks are required to optimize the dose of anti-hypertensive medications

Feline Aortic Thromboembolism

Feline Aortic Thromboembolism

An aortic thromboembolism is a blood clot that has developed within the heart.  

It typically lodges at the distal aorta, often termed a “saddle thrombus”, which supplies the rear limbs with blood.  

This condition makes the affected limbs painful, cold to touch, and typically non-functional.  

Approximately 50% of patients with this condition are also in at least mild congestive heart failure at the time the clot is noted.

Plavix has been recently shown by the FAT CAT study to be the most effective antiplatelet medication in our feline friends.  

Urgent medical attention is necessary if these signs are noted or return.

Please use caution when handling a patient that you believe may have developed a thrombus.

These animals are typically in severe pain and may scratch or bite.  

Also, they likely cannot handle a high degree of stress due to their fragile status.  Be gentle, place the patient into a carrier, and contact a 

veterinarian as soon as possible.

Restrictive Cardiomyopathy in Cats

Restrictive Cardiomyopathy in Cats

Restrictive Cardiomyopathy is a primary myocardial disease wherein the heart muscle is damaged.

The myocardium becomes infiltrated with fibrous scar tissue that prevents normal function (failure of both squeezing and relaxation).  

This is a non-curable and progressive disease.  As the ventricle does not relax normally, the left atrium dilates as it is unable to push the blood into the small left 

ventricular chamber.  This eventually can lead to the development of congestive heart failure (fluid in the lungs), which is a medical emergency that makes breathing very difficult.  This disease is typically progressive; however, the rate of progression is highly variable.  Recheck echocardiograms are necessary to monitor the rate of change, chamber sizes, and determine if any additional medications or adjustments are indicated.

Once the left atrium has dilated, affected patients are at an increased risk for thromboembolic disease.  

This is when a blood clot forms within the left atrium or auricle, which can dislodge and go to various points within the body.  

The most common location is the distal aorta (often termed a “saddle thrombus”), which supplies the rear limbs with blood.  When this happens, affected patients are very painful, the limbs cool to touch, and the legs are typically non-functional.  

The right front leg is the second most common location.  Any other clinical signs are determined by the site of the clot lodging.  

This could include sudden death if the brain were to be affected by this.  Anti-platelet medications are utilized to minimize the chances of this developing; however, no medications are 100% effective in preventing this condition.  

Plavix has been recently shown by the FAT CAT study to be the most effective antiplatelet medication in our feline friends.  

If you notice any clinical signs or leg weakness, consider it a medical emergency.

Hypertrophic Cardiomyopathy in Cats

Hypertrophic Cardiomyopathy in Cats

Hypertrophic Cardiomyopathy is a primary myocardial disease wherein the heart muscle is damaged.

The myocytes (muscle cells) become markedly thickened and replicate in a non-uniform pattern.

This causes the ventricle (pumping chamber) to become severely thickened, which reduces the chamber size for blood.  

This disease is characterized by a diastolic (filling) failure.  

This causes the left atrium to dilate as it is unable to push the blood into the small left ventricular chamber.  

This eventually can lead to the development of congestive heart failure (fluid in the lungs), which is a medical emergency that makes breathing very difficult.  

This disease is typically progressive; however, the rate of progression is highly variable.  

Recheck echocardiograms are necessary to monitor the rate of change, chamber sizes, and determine if any medications or adjustments are indicated.

Once the left atrium has dilated, affected patients are at an increased risk for thromboembolic disease.  

This is when a blood clot forms within the left atrium or auricle, which can dislodge and go to various points within the body.  

The most common location is the distal aorta (often termed a “saddle thrombus”), which supplies the rear limbs with blood.  

When this happens, affected patients are very painful, the limbs cool to touch, and the legs are typically non-functional.  

The right front leg is the second most common location.  Any other clinical signs are determined by the site of the clot lodging.  This could include sudden death if the brain were to be affected by this.  

Anti-platelet medications are utilized to minimize the chances of this developing; however, no medications are 100% effective in preventing this condition.

Plavix has been recently shown by the FAT CAT study to be the most effective antiplatelet medication in our feline friends.  

If you notice any clinical signs or leg weakness, consider it a medical emergency.

Dilated Cardiomyopathy in Cats

Dilated Cardiomyopathy in Cats

Dilated Cardiomyopathy is a primary myocardial disease wherein the heart muscle is damaged and becomes very weak.  

In cats, this is usually idiopathic, but can develop secondary to nutritional deficiencies (specifically Taurine deficiency).  

The left ventricle dilates and has a marked systolic dysfunction (pump dysfunction).  

This causes an elevation in left ventricular and left atrial pressures as the poorly pumping chamber continues to dilate.  

Eventually, this results in dilation of the left atrium and fluid accumulation within the lungs (congestive heart failure).  

This makes breathing difficult and requires urgent medical attention.

Unfortunately, there is likely no cure for this disease (unless Taurine deficiency is the underlying etiology).  

Ongoing rechecks and medical management are utilized to maximize the quality of life for affected patients.  The disease progression is variable, with some patients doing well for years and others progressing into congestive heart failure rapidly.  

This disease is also frequently associated with the development of arrhythmias (abnormal electrical beats) that can predispose affected patients to sudden death.  

Additional diagnostics, such as 24 hour Holter Monitors, may be recommended based on our initial findings.  

If any clinical signs of arrhythmias such as a “dazed” appearance or collapse are noted, please contact your trusted veterinarian or your local emergency clinic immediately.

Congestive Heart Failure in Cats

Congestive Heart Failure in Cats

Left-Sided congestive heart failure occurs when the pressure in the blood vessels in the lungs increases causing fluid to leak from the vessels into the surrounding lung tissue.  

Right-Sided congestive heart failure is a similar process where the fluid accumulates within the pleural space (around the lungs) or the abdomen (ascites).  

This condition makes it difficult to exchange oxygen causing difficulty breathing, increased respiratory rate or effort, cyanosis (blue color to gums or tongue), and/or weakness and/or collapse with exertion.  

Coughing is a very rare sign of congestive heart failure in our feline friends and is usually associated with feline asthma or heartworm disease.

Congestive heart failure is a life-threatening condition and your pet should be evaluated as soon as signs are noted, which may require an emergency hospital visitation.