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

Abstract

BackgroundDilated cardiomyopathy (DCM) is a common cause of morbidity and mortality in the Irish Wolfhound (IW). However, the benefit of medical treatment in IW dogs with preclinical DCM, atrial fibrillation (AF), or both has not been demonstrated.ObjectivesCompare the time to develop congestive heart failure (CHF) or sudden death in IW dogs with preclinical DCM, AF, or both receiving monotherapy with pimobendan, methyldigoxin, or benazepril hydrochloride.AnimalsSeventy‐five client‐owned IW dogs.MethodsIrish Wolfhound dogs were prospectively randomized to receive pimobendan (Vetmedin®)1, benazepril HCl (Fortekor®)2, or methyldigoxin (Lanitop®)3 monotherapy in a 1:1:1 ratio in a blinded clinical trial. The prospectively defined composite primary endpoint was onset of CHF or sudden death. To assure stringent evaluation of treatment effect, data from dogs complying with the study protocol were analyzed.ResultsSixty‐six IW fulfilling the study protocol included 39 males, 27 females; median (interquartile range) age, 4.0 years (3.0–5.0 years) and weight, 70.0 kg (63.0–75.0 kg). Primary endpoint was reached in 5 of 23 (21.7%) IW receiving pimobendan, 11 of 22 (50.0%) receiving benazepril HCl, and 9 of 21 (42.9%) receiving methyldigoxin. Median time to primary endpoint was significantly longer for pimobendan (1,991 days; 65.4 months) compared to methyldigoxin (1,263 days; 41.5 months; P = .031) or benazepril HCl‐(997 days; 32.8 months; P = .008) treated dogs.Conclusions and Clinical ImportanceIn IW dogs with preclinical DCM, AF or both, pimobendan monotherapy significantly prolonged time to onset of CHF or sudden death than did monotherapy with benazepril HCl or methyldigoxin.

Multiple Genetic Associations with Irish Wolfhound Dilated Cardiomyopathy

“…In addition, this provides evidence that individuals diagnosed with AF should be carefully monitored and regularly presented for heart testing to ensure that they do not yet require treatment for DCM. There is also the potential to improve the survival of individuals diagnosed with AF by treating them with drugs such as pimobendan prior to the development of DCM or heart failure [17], in addition to receiving therapy for AF.…”

“…Canine osteosarcoma often results in euthanasia due to poor quality of life in affected dogs and survival following diagnosis is typically less than one year [12, 15, 16]. In contrast, the prognosis of dogs with heart disease such as atrial fibrillation or DCM is better when diagnosed and treated early with median time to death reported to be up to 4 years following early heart disease diagnosis [17]. There is limited literature on pneumonia in IWH [18, 19] but Greenwell and Brain [13] reported a breed predisposition compared to other breeds treated for pneumonia within a specialist small animal hospital.…”

“…If AF is a potential precursor to DCM, the time from diagnosis of AF to DCM is important; if it is several years then the presence of AF could be less of a concern than if it is merely a few months. Also if AF is a precursor to DCM there is the potential to give individuals diagnosed with AF drugs such as the phosphodiesterase III/calcium sensitizing drug, pimobendan, to improve survival [17]. In addition to the potential clinical implications of AF diagnosis and potential early interventions for both dogs and humans, if AF can be shown to be related to DCM for genetic association testing, this diagnosis can be used to test for associated DCM genetic implication.…”

Clinical Trials in Veterinary Medicine: A New Era Brings New Challenges

“…The use and reporting of ITT and PP methods in both the human42, 46, 47 and veterinary3, 4, 5, 6, 7, 8, 9, 13 medical literature varies widely. In many studies, key pieces of information, including original number of patients recruited and randomized, how missing data was treated, and exactly which analysis methods and data sets were used, are lacking 48, 49.…”

“…A glance through recent issues of the Journal of Veterinary Internal Medicine identifies prospective randomized clinical trials (RCTs) involving dogs,1, 2, 3, 4, 5, 6, 7, 8, 9 cats,10, 11, 12, 13 cows,14, 15 and horses16, 17 that cover the fields of neurology,1, 8 oncology,3, 5 cardiology,4, 6, 12 and internal medicine 2, 9, 10, 11, 13, 14, 15, 16, 17. Collectively, these findings suggest that we have entered into an era of prospective veterinary RCTs.…”