Severely Abnormal Heart Rhythm in Dogs

There are a variety of conditions associated with abnormal heart rate, including but not limited to sinus bradycardia (SB), which is recognized as a slower-than-normal rate of impulses in the sinus node. Arrhythmia, which is recognized as an abnormal variation in the cycling of impulses that regulate the heart's beating action. And, most one of the most severe, ventricular fibrillation (V-Fib) which is a condition where the ventricle muscles (muscles located in the rear chamber of the heart) in the heart begin contract and contort in a fashion that is extremely disorganized, which is opposite the bodies expected output, making the muscles quiver. In all cases, abnormal heart rate reasons and symptoms are severe and acted upon with a high sense of urgency. Do not take a wait and see approach if your dog is breathing slowly, losing consciousness, or collapsing.

Signs of an abnormal heart rhythm may vary.

• Collapsing is common among boxers, bulldogs, and German shepherds.
• Collapsing, along with fainting, is a possibility for Cocker Spaniels, Dachshunds, Miniature Schnauzers and West Highland White Terriers.

Collapsing is often linked to left-sided congestive heart failure faint.

For any dog breed and cats, there will be noticeable signs of:

• Moving slowly
• Difficulty breathing
• Coughing
• Lethargy
• Seizures
• General weakness
• Loss of consciousness

There are cases where the canine may suddenly die before having the opportunity to be treated.

Types

Although arrhythmias (abnormal heart rhythms) in dogs can affect all dogs, certain types of arrhythmias more commonly affect certain breeds.

• Atrial Fibrillation - Most common in Boxers, Doberman Pinschers, Great Danes, Irish Wolfhounds, Newfoundlands and other large breeds
• Arrhythmogenic right ventricular cardiomyopathy (ARVC) - specifically linked to Boxers, English Bulldogs, American Staffordshire and seldom in cats
• Heart block - Can be common in any dog breed, along with cats
• Myocarditis - Can be common in any dog breed but most prevalent in medium to larger dogs
• Sick Sinus Syndrome - Most common in Boxers, Cocker Spaniel, Dachshunds, Miniature Schnauzers, West Highland White Terriers
• Ventricular Arrhythmias - Most common in Boxers, Bulldogs and German Shepherds

A decrease in blood flow to the rest of the body due to systolic myocardial failure is a primary cause of an abnormal heart rhythm. This means that the enlarged heart muscle (cardiomyopathy) cannot properly function, which affects blood circulation to the rest of the dog's body. Other causes include:

• Impedance to cardiac inflow - linked to abnormalities in the heart or fluid around the heart
• Pressure overload - linked to stress around the heart wall
• Volume overload - linked to heart-related diseases such as hyperthyroidism or anemia

Although enlarged hearts cannot be recognized by a stethoscope and issues related to abnormal heart rhythms may go under the radar, if a veterinarian seems symptoms of heart-related issues, then electrocardiograms (EKG), cardiac ultrasound or X-rays are used to determine the problem. During a 24-hour time span of EKG monitoring, a veterinarian can determine whether a dog is in need of medication (ex. solatol), a pacemaker or whether there's a possibility that the animal may grow out of it as it gets older, which German Shepherds commonly do.

Common tests include:

• Chemical blood profile
• Urinalysis
• Electrocardiogram (ECG)
• Ultrasound

For some dogs, the breathing may be too slow while other dogs' heartbeats are due to rapid breathing. Dogs with sick sinus syndrome are most likely associated with heartbeats that are too slow. Veterinarians will compare the results of other breeds to see which type of abnormal breathing resolutions are most closely aligned with a breed and whether that particular breed of dog matches the same syndromes. A healthy dog's heartbeat is between 80 to 150 beats per minute.

Treating dogs with abnormal heart rhythms is usually done with these techniques:

• 24-hour monitoring (ex. Holter monitoring)
• Antiarrhythmics
• Cardiac troponin I levels
• C-reactive protein
• Echocardiography
• Medication (ex. Atenolol, corticosteroids, digoxin, diltiazem)
• Pacemaker
• Radiography (X-rays)
• Recording electrocardiograms

After the behavior of the abnormal heart rate is determined as too fast or too slow, one of the above techniques will be used to resolve the issue, assuming the dog is not too far along. For some dogs, and if not treated immediately, the possibility of dying within a few minutes after collapsing is not a foreign result. However, if the veterinarian can catch the issue in time, additional testing from EKGs and Holter monitoring will be needed to confirm that the abnormal heart rhythm does not re-occur.

The dog will either stand or lay down with electrodes attached to his or her elbows and knees. Besides a gel that will be rubbed onto its skin, the dog is in no particular danger. Holter monitoring with a small pack may last 24 to 72 hours.

Outside of the gel being removed from the EKG or the small pack taken off from Holter monitoring, a dog should be able to get back to normal within 24 to 72 hours.

Should the dog need more serious surgery, such as with a pacemaker, that is a life-long procedure, but the actual placement of the pacemaker should take two to four weeks. Pet owners should bring in their dogs every six months to make sure the pacemaker is working properly.

The instruments are designed to last approximately eight to 10 years, which is a reasonable time for the average dog's lifespan. Should the pacemaker need to be replaced again, it will start to slow the heart rate down again. Pet owners should immediately revisit a veterinary again to see what are the best steps to take at this point.

The cost for severely abnormal heart rate is directly correlated to the type and reason. The tests involved to reach a point of identification will cost at minimum $380 and can reach $1,150 Treatment depends on the type of abnormal heart condition as well, with a high cost of $4,200 for a pacemaker in your dog.