The prevalence of cardiomyopathy in the Irish wolfhound: a clinical study of 500 dogs

Abstract

The prevalence of cardiomyopathy in Irish wolfhounds was evaluated by retrospective review of the results of cardiovascular examinations carried out in 500 dogs presented for veterinary services at the author's practice. Abnormalities were found in 209 (41.8%) of the dogs examined. Dilated cardiomyopathy (DCM) was diagnosed in 121 (24.2%) of the dogs and was accompanied by atrial fibrillation in 106 dogs. Seventeen dogs were suffering from advanced congestive heart failure (CHF), and 55 dogs were suffering from mild to moderate CHF as a result of DCM. Congestive heart failure was most commonly characterized by mild to severe pleural effusion due to right-sided heart failure in addition to pulmonary edema. Rhythm disturbances without evidence of DCM were detected in 48 dogs. Forty dogs had echocardiographic abnormalities without signs of DCM. Soft to moderate mitral regurgitations were diagnosed in 13 (2.6%) of these 40 dogs examined. In 39 dogs that died as a result of DCM, the median survival time from the time of diagnosis was 5.1 months, and in 59 dogs with DCM that are still alive, the median survival time is 15.7 months.

Finding cardiovascular disease genes in the dog

“…Contributing to its' small gene pool is the fact that the breed suffered a severe bottleneck in the mid 1800's, such that Irish Wolfhound were considered by many to be extinct. The breed is at high risk for dilated cardiomyopathy, with the disorder possibly affecting as much as one-third of the population (www.iwclubofamerica.com) 62 . Once the disease gene is identified, a strict screening and removal policy that would restrict dogs carrying even one disease allele from producing registered dogs would likely destabilize the gene pool, resulting in many new recessive disorders "popping-up" in the breed.…”

Lifespan and disease predispositions in the Irish Wolfhound: A review

“…The mean age at death for males and females that had survived their first year of life was 4.95 + 0.94 years and 6.59 + 0.95 years respectively. There was a high mortality in the first year of life, only 61.29% of males and 72.92% of females born alive reaching one year.of age. Given that effective vaccines and antibiotics were not available in veterinary science at the time, it is likely that infectious diseases were an important part of these early losses.…”

“…It was suggested that an autosomal dominant pattern of inheritance would best fit the observed distribution (17,72). The most recent study (9) found that a mixed inheritance model with polygenic effects and a segregating major gene explained the observed DCM cases best.…”

“…The majority of epidemiological studies report an increased risk for males (4,9,64,68,71,72), but a few studies found no sex predisposition (7,10,56,67).…”

Long‐term Outcome of Irish Wolfhound Dogs with Preclinical Cardiomyopathy, Atrial Fibrillation, or Both Treated with Pimobendan, Benazepril Hydrochloride, or Methyldigoxin Monotherapy

“…The Irish Wolfhound (IW) breed has been noted for its high prevalence of dilated cardiomyopathy (DCM), atrial fibrillation (AF), or both 1, 2, 3, 4, 54, 5, 6 In 1 large study of 1,038 IW dogs prospectively screened between 1990–2004, approximately 29% were affected,7 and in selected populations of IW dogs, AF has been reported in up to 21% of screened animals 4, 5, 6, 7, 4, 7. Moreover, AF may develop before structural or functional changes become apparent, and some affected dogs may progress to DCM and congestive heart failure (CHF) 6, 7, 8…”