Irish Wolfhound cardiac data collected over the last 25 years includes over 5,000 EKGs, 1,000 echocardiograms, and follow up on more than 800 hounds. Examining this data gives some foundation for testing suggestions for the cardiac health of your hound.
ALL Irish Wolfhounds should have a YEARLY EKG and auscultation.
Cardiac studies utilized 6 lead EKGs and showed that more than 1/2 of tested hounds had an EKG abnormality by age 7. However follow-up showed us only arrhythmias and first degree AV block predicted future problems. These can all be diagnosed by doing a long (usually lead 11) rhythm strip available from your veterinarian as well as at screening clinics.
Atrial fibrillation predicts cardiac disease in the IW. The incidence of atrial fibrillation increases as the hound ages. If your hound is normal at age 3 that does NOT assure he will be normal in the coming years. Atrial fibrillation and progressive cardiomyopathy responds to treatment and the treatment is well tolerated and affordable. It does not matter if your hound is in the show ring or other competition or just in your heart and on your couch-he/she will benefit from this screening test.
Twenty two percent of the Irish Wolfhounds examined in the heart clinics had “innocent” murmurs. These murmurs are common in giant breeds and do not cause any problem with heart function. They have not been documented to progress. The incidence of congenital heart disease (born with it) is low in the IW but tricuspid dysplasia, aortic stenosis, and atrial septal defects have been found on our screening tests.
To diagnose these more serious murmurs it is recommended that a hound have an auscultation by a board certified cardiologist with his first EKG.
If atrial fibrillation or a murmur worrisome to your vet is found on the yearly screening the hound needs referral to a cardiologist and an echocardiogram.
If all is well he still needs an EKG next year!
About 3% of hounds are diagnosed with VPCs or abnormal heart beats coming from the lower chambers of the heart. There is a higher incidence of sudden death in these hounds and they need referral to a cardiologist and a holter monitor.
OFA and CHIC
At this time OFA and CHIC certification require that the yearly EKG and auscultation are done by a board certified cardiologist. Negotiations are underway to have the EKG sent to the cardiologist for interpretation and to require only the initial auscultation be done by a cardiologist.This will make participation accessible to more owners.
Heart testing recommendations for breeding stock
1. All breeding stock should have an EKG and an auscultation by a cardiologist before breeding.
The EKG should be done as close to the breeding time as possible.
Any hound with a suspicious murmur should have an echocardiogram before breeding.
The incidence of congenital valve disease is very low in the IW but is a significant problem in many breeds. Dr. Tyrrell feels it is not unwise for all IW breeding stock to have an initial echocardiogram to assure this continues.
2. Dogs with a strong family history should be bred with caution.
Efforts are underway to confirm the mode of inheritance of atrial fibrillation in the Irish Wolfhound.
It is thought to be autosomal (not sex linked) dominant with variable penetrance. This means it is definitely inherited. If a hound with afib is bred to a hound with no afib EACH puppy in the litter has a 50% chance of having afib..... However it gets much more complicated (that old variable penetrance) as hounds have been documented to be normal until age 9 and then develop afib.
The average age of onset for afib is 5 years - often past the breeding age. Discussions about the known incidence of afib and cardiomyopathy in grandparents and litter mates of the prospective sire and dam are very helpful in planning breedings.
3. Any dog with atrial fibrillation before age 5 should not be bred.
A follow up study for hounds with atrial fibrillation is planned. At the present time it appears hounds developing afib at a young age progress more quickly to cardiomyopathy.
With 20% of hounds known to be affected we CANNOT eliminate all afib hounds from the breeding pool but it is a reasonable goal to not propagate early onset cardiomyopathy.
There is no marker at the present time to tell us which hounds will progress quickly to cardiomyopathy but until there is better data. It is recommended that hounds developing afib before the usual age of onset not be bred.
If a young male important to your breeding plans is found to have afib and normal function on echocardiogram you may wish to collect him and watch his clinical course before making breeding decisions .
4. Any bitch in atrial fibrillation should not be bred.
There are significant demands on the cardiovascular system during pregnancy and after delivery. There is significant chance you could endanger your bitch.
5. Any IW with VPCs (risk of sudden death) or APCs (risk of developing atrial fibrillation) on their EKG should discuss this with a cardiologist familiar with IWs before breeding.
The hound with VPCs will need a holter and if it shows dangerous rhythm problems and medication is needed, strongly consider not breeding this hound. If it a bitch she should not be bred as there is risk to her litter.
At the present time there is no evidence that this is an inherited condition but it is possible.
All evidence suggests APCs are a precursor to afib but there is no data yet to tell us when that may happen. Any bitch with APCs should have an echo before breeding to make sure her left atrial size is normal.
6. Any IW with a murmur should be seen by a cardiologist before breeding to see if an echo is needed and to assure (if a bitch) that pregnancy will be tolerated.
7. If you have collected semen for future breedings results of the hound’s yearly EKG and original auscultation by a cardiologist should be recorded in a data base or easily available from your personal records.
If you own a frequently used sire (more than 5 litters) an initial echo along with the EKG and auscultation is recommended.
Only 47% of hounds with afib die from cardiac failure but this is still the number two killer of our hounds. The EKG/ Echo study showed IW cardiac disease is unique and can be detected in nearly all cases by a screening EKG. An early auscultation by a cardiologist can pick up serious valve disorders and keep the incidence low in IWs.
With yearly simple and inexpensive testing we can treat our hounds before they develop cardiomyopathy and plan breedings wisely.
The incidence of atrial fib in our data is 20% overall but it may be much higher. Please participate in the planned atrial fibrillation follow-up study and the Life Cycle 11 study to help our future hounds.