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German Shepherd Dog Inherited Ventricular Arrhythmia and Shiloh Shepherds
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GSDIVA FAQ
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GLOSSARY OF TERMS
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HOLTER MONITOR
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what is gsdiva
German Shepherd Dog Inherited Ventricular Arrhythmia (GSDIVA), is an inherited heart condition that can cause sudden death in Shiloh Shepherd puppies. The amount of the Ventricular Arrhythmias (VA) is age dependent. Before 12 weeks (3 months) of age Premature Ventricular Contractions (PVCs) are rare but gradually increase with a peak frequency of VA, including Ventricular Tachycardia (VT), between 24 to 28 weeks (6 to 7 months) of age. Death most often occurs between the age of 16 to 32 weeks (4 to 8 months) and usually during sleep in the early morning hours or a resting period after exercise. After 28 weeks (7 months) the number of VA decreases such that many dogs after 100 weeks (25 months) of age no longer have arrhythmias and are not at risk. The most severely affected dogs do continue to have occasional VA. Diagnosis is determined by using a Holter Monitor. Breeding from lines of affected dogs is not recommended.
What dogs get arrhythmias
All breeds and ages of dogs can get arrhythmias. Some specific arrhythmias are identified in specific breeds. The cause and the treatment vary widely depending on the diagnosis.
sYMPTOMS
There are no outward symptoms of GSDIVA and the dog appears to be healthy and normal until sudden death occurs - caused by the degeneration of VT into Ventricular Fibrillation (VF).
DIAGNOSIS
The only way to diagnose GSDIVA is by Holter monitoring. Ideally between the ages of 24 and 28 weeks (6 and 7 months).
TREATMENT
With use of antiarrhythmic agents. A combination of the drugs Mexiletine and Sotalol has been found to be the most effective in treating German Shepherd Dogs. Stress and excitement should be limited. Note: All antiarrhythmic drugs have the potential to cause Proarrhythmia and should be used with caution.
FROM THE JOURNAL OF VETERINARY INTERNAL MEDICINE
Genetic Analysis of Ventricular Arrhythmia in Young German Shepherd Dogs
Spontaneous Ventricular Arrhythmia (VA) and sudden death occur in young German Shepherd Dogs (GSDs). The disorder ranges in severity from infrequent and non-life-threatening single Premature Ventricular Contractions (PVCs) to multiple episodes of rapid polymorphic Ventricular Tachycardia (VT). Dogs with VT are most likely to die suddenly. No other clinical indicators of abnormality are apparent and pathological examination of the hearts of dogs that die suddenly reveal morphologically normal hearts.
A window of vulnerability for the presence of VA and sudden death exists between approximately 3 and 18 months of age, with peak affectedness occurring at approximately 6 – 7 months of age. Affected dogs rarely have VA after 24 months of age and when they do, it is infrequent. The trait of VT is most commonly observed in dogs lying at rest and during rapid eye movement sleep. Because of the age and behavioral dependence of the expression of this disease, extensive observation via 24-hour ambulatory ECG monitoring (Holter monitoring) is often required to ascertain disease presence and its severity. read full report >>>
Spontaneous Ventricular Arrhythmia (VA) and sudden death occur in young German Shepherd Dogs (GSDs). The disorder ranges in severity from infrequent and non-life-threatening single Premature Ventricular Contractions (PVCs) to multiple episodes of rapid polymorphic Ventricular Tachycardia (VT). Dogs with VT are most likely to die suddenly. No other clinical indicators of abnormality are apparent and pathological examination of the hearts of dogs that die suddenly reveal morphologically normal hearts.
A window of vulnerability for the presence of VA and sudden death exists between approximately 3 and 18 months of age, with peak affectedness occurring at approximately 6 – 7 months of age. Affected dogs rarely have VA after 24 months of age and when they do, it is infrequent. The trait of VT is most commonly observed in dogs lying at rest and during rapid eye movement sleep. Because of the age and behavioral dependence of the expression of this disease, extensive observation via 24-hour ambulatory ECG monitoring (Holter monitoring) is often required to ascertain disease presence and its severity. read full report >>>
arrhythmia
An irregular heartbeat. Arrhythmias are heart-rhythm problems - they occur when the electrical impulses to the heart that coordinate heartbeats are not working properly, making the heart beat too fast, too slow or inconsistently.
Too fast - Tachycardia | Too slow - Bradycardia | Too early - Premature Contraction | Too irregularly - Fibrillation.
Too fast - Tachycardia | Too slow - Bradycardia | Too early - Premature Contraction | Too irregularly - Fibrillation.
anti-arrhythmic
Antiarrhythmic drugs are used to treat abnormal and irregular heart rhythms.
proarrythmia
The provocation of a new arrhythmia or the aggravation of a pre-existing arrhythmia.
electrocardiogram (ecg)
A test that records the electrical activity of the heart over a period of time, as detected by electrodes attached to the surface of the skin and recorded by a device external to the body.
Premature Ventricular Contraction (PVC)
Are heartbeats that occur earlier than they should. These early beats briefly interrupt the heart's rhythm. Early heartbeats can happen in the upper chambers (atria) or lower chambers (ventricles) of the heart. With PVCs, the ventricles beat early and an extra beat is followed by a pause and then a stronger heartbeat. The heart fills with more blood during the pause following the PVC, giving the next beat extra force. This pattern may occur randomly or at definite intervals. Single - 1 PVC | Pairs - 2 PVCs together | Runs - 3 or more PVCs together
Ventricular Arrhythmia (VA)
This is an abnormal heart rhythm the comes from the lower chambers of the heart (the ventricles). Rhythms of this type include ventricular tachycardia (VT) and ventricular fibrillation (VF). Both are life threatening arrhythmias.
Ventricular Tachycardia (VT)
This is a fast heart rhythm that occurs in one of the ventricles of the heart. It is like one electrical short circuit that races in a circle. In a VT, the heart beats with each race around the circuit at rates from 150 to 250 bpm. If left untreated, some forms of ventricular tachycardia may get worse and lead to ventricular fibrillation which can be life-threatening.
Ventricular Fibrillation (VF)
Originates from many different locations in the ventricles, each one trying to signal the heart to beat. In this case, the heart beats much faster than normal, sometimes over 300 beats a minute. The lower chambers quiver instead of contract and very little, if any, blood is pumped from the heart to the rest of the body.
What is a Holter Monitor
A Holter monitor is a noninvasive method of continuously recording a dog's heart rate and heart rhythm on an electrocardiogram (ECG). The monitor is worn for 24 hours or longer and during normal activity. The data recorded by the monitor is sent for analysis by a Certified Technician or Cardiologist and a report is generated. This report indicates the number of PVCs (Premature Ventricular Contractions) detected during the 24-hour period.
what is normal
The normal heart rate for dogs varies based on the size of the dog, however the general range is 60–160 beats per minute.
PVCs appear to be somewhat common in dogs so a low number is acceptable as there are temporary conditions that may cause them to occur. A PVC score of zero or very close to zero is the best result.
Large numbers of single PVCs or PVCs in pairs or runs are cause for concern. These affect the heart output which has consequences for the health of the dog. The heart has to work extra hard to compensate or the body and brain gets insufficient blood supply.
Single - 1 PVC | Pairs - 2 PVCs together | Runs - 3 or more PVCs together
Less than 50 PVCs in a 24 hour period is considered normal as long as any PVCs recorded are not in runs.
Between 50 - 100 PVCs (not in runs) is acceptable as long as the results are consistent when re-tested. Re-testing is necessary as the disease progresses over time and repeating the Holter test every year or two is recommended.
More than 100 PVCs during the 24 hour period can be considered as having the disease and the dog will be likely to pass it on to their progeny.
PVCs appear to be somewhat common in dogs so a low number is acceptable as there are temporary conditions that may cause them to occur. A PVC score of zero or very close to zero is the best result.
Large numbers of single PVCs or PVCs in pairs or runs are cause for concern. These affect the heart output which has consequences for the health of the dog. The heart has to work extra hard to compensate or the body and brain gets insufficient blood supply.
Single - 1 PVC | Pairs - 2 PVCs together | Runs - 3 or more PVCs together
Less than 50 PVCs in a 24 hour period is considered normal as long as any PVCs recorded are not in runs.
Between 50 - 100 PVCs (not in runs) is acceptable as long as the results are consistent when re-tested. Re-testing is necessary as the disease progresses over time and repeating the Holter test every year or two is recommended.
More than 100 PVCs during the 24 hour period can be considered as having the disease and the dog will be likely to pass it on to their progeny.
where to rent
Below is a list of where you can buy or rent a Holter Monitor. There are also several Shiloh Shepherd Breeders that have purchased their own Holter Monitor. Please contact your breeder for more information.
how to use
Holter monitoring is not painful for your pet. The monitor is about the same size and shape as an iPhone and weighs approximately 7 oz. The monitor is attached to the dog by leads and adhesive electrodes in the same way that it would be placed on a human patient. It is then placed in a small pouch on the dog’s back. A vest wraps around the dogs chest to protect the leads and electrodes and the pouch is held in place by a velcro strap or can be attached to a harness. Special care should be taken when removing the electrodes from the skin since they are glued in place.
These web sites offer a great explanation of how to attach the Holter Monitor and also contain pictures and videos as well as other helpful information about the process.
These web sites offer a great explanation of how to attach the Holter Monitor and also contain pictures and videos as well as other helpful information about the process.
Below are some Shiloh Shepherds wearing the Holter Monitor and protective vest.