Ryan Fries

Prevalence of the Myosin-Binding Protein C Mutation in Maine Coon Cats

BACKGROUND An autosomal dominant mutation has been identified in the myosin-binding protein C (MYBPC3) gene of Maine Coon cats. This mutation changes a conserved amino acid and computationally alters the protein conformation of this gene in Maine Coon cats with hypertrophic cardiomyopathy. The prevalence of this mutation is unknown. OBJECTIVE To determine the genetic prevalence of the MYBPC3 mutation in a large cohort of predominantly Maine Coon cats. ANIMALS Three thousand three hundred and ten DNA samples (blood or buccal swab) from cats. METHODS This retrospective study reviewed the Veterinary Cardiac Genetics Laboratory database at Washington State University for samples submitted for evaluation of the Maine Coon MYBPC3 mutation. The data were analyzed with respect to the breed of cat, mutation status (negative, heterozygous, homozygous), and geographic origin of the submission. RESULTS In the population of cats studied, Maine Coon cats accounted for 100% of all cats positive for the mutation, and the worldwide percentage of Maine Coon cats carrying the MYBPC3 mutation was 34%. CONCLUSIONS AND CLINICAL IMPORTANCE The prevalence of the mutation (heterozygous or homozygous) was very similar among countries of submission, suggesting that the 34% mutation rate of the tested samples is a reasonable estimate of the true prevalence of the mutation within the breed. Because of the high prevalence of this mutation, a breeding recommendation to eliminate all cats with the mutation could have a substantial impact on the gene pool. Additional studies are indicated to explore the relationship between genotype and clinical outcome in affected cats.

Effect of oral administration of pimobendan in cats with heart failure

OBJECTIVE To determine the effect of PO administration of pimobendan on clinical and echocardiographic variables and survival time in cats with heart failure characterized by ventricular systolic dysfunction. DESIGN Retrospective cohort study. ANIMALS 27 client-owned cats (16 male and 11 female) with heart failure, treated with pimobendan (mean ± SD dosage, 0.26 ± 0.08 mg/kg [0.118 ± 0.036 mg/lb], PO, q 12 h). PROCEDURES Information on medical history, laboratory results, diagnostic imaging findings, treatments received, and survival time were obtained from medical records of cats that received pimobendan because of cardiac disease. When possible, additional follow-up information was obtained through telephone interviews with referring veterinarians and owners. RESULTS The mean ± SD age of all 27 cats was 8.9 ± 5.2 years. All cats had received several cardiac medications. Types of heart disease represented included unclassified cardiomyopathy (CM; n = 11 [41%]), dilated CM (8 [30%]), arrhythmogenic right ventricular CM (4 [15%]), congenital heart disease (3 [11 %]), and hypertrophic CM with regional hypokinesis (1 [4%]). All cats had ventricular systolic dysfunction. One cat with systolic anterior motion of the mitral valve became severely hypotensive after initial administration of pimobendan and was excluded from the survival analysis. Median survival time was 167 days (95% confidence interval, 32 to 339 days). CONCLUSIONS AND CLINICAL RELEVANCE Pimobendan appeared to be well tolerated in cats with heart failure characterized by ventricular systolic dysfunction of various etiologies. Cats with systolic anterior motion of the mitral valve may develop systemic hypotension when treated with pimobendan. Additional studies are needed to establish dosages for pimobendan and its effects before it can be recommended for treatment of cats with CHF.

Use of procainamide for conversion of acute onset AF following pericardiocentesis in a dog.

A 9 yr old spayed female golden retriever was evaluated for anorexia and suspected gastric dilatation. Subsequent evaluation the following day determined the dog to have pericardial effusion. Muffled heart sounds and jugular pulses were noted on physical exam, and the dog was diagnosed with pleural and pericardial effusion. A sinus rhythm with a rate of 142 beats/min was documented on a surface electrocardiogram (EKG). Following pericardiocentesis, the heart rate increased to 260 beats/min, the rhythm became irregular, and the systemic blood pressure decreased. Atrial fibrillation (AF) was confirmed by EKG. Procainamide was administered IV over 15 min, resulting in successful conversion of AF to sinus rhythm and clinical improvement. Procainamide is one of several antiarrhythmic medications that are used for the conversion of acute AF in humans; however, its utility and efficacy in dogs in the setting of AF has not previously been reported. This case highlights a unique complication of performing a pericardiocentesis that requires immediate treatment and describes a potential treatment option for the conversion of acute AF in dogs.

Primary cardiac tumor presenting as left ventricular outflow tract obstruction and complex arrhythmia

An adult female mixed breed dog presented for recurrent collapsing episodes over several weeks. Holter evaluation revealed periods of sinus arrest and echocardiography identified a soft tissue mass with subsequent severe dynamic obstruction of the left ventricular outflow tract. The patient was euthanized five days after presentation for severe dyspnea. Necropsy revealed an irregular mass circumferentially lining the left ventricular outflow tract as well as multiple myocardial metastases. The final diagnosis was an undifferentiated pleomorphic endocardial sarcoma.

Severe hyperkalemia presenting with wide‐complex tachycardia in a puppy with acute kidney injury secondary to leptospirosis

OBJECTIVE To describe a case of hyperkalemia coinciding with wide-complex tachycardia (WCT) in a dog with acute kidney injury secondary to leptospirosis infection. CASE SUMMARY An 11-week-old Golden Retriever-Standard Poodle cross puppy was referred for acute kidney injury and hepatopathy. WCT coinciding with marked hyperkalemia was identified on presentation. Tachycardia persisted until resolution of hyperkalemia. NEW OR UNIQUE INFORMATION PROVIDED To our knowledge, this is the first report of severe hyperkalemia presenting with WCT in a dog. Hyperkalemia should be considered a differential for WCT in dogs.Objective To describe a case of hyperkalemia coinciding with wide-complex tachycardia (WCT) in a dog with acute kidney injury secondary to leptospirosis infection. Case summary An 11-week-old Golden Retriever–Standard Poodle cross puppy was referred for acute kidney injury and hepatopathy. WCT coinciding with marked hyperkalemia was identified on presentation. Tachycardia persisted until resolution of hyperkalemia. New or unique information provided To our knowledge, this is the first report of severe hyperkalemia presenting with WCT in a dog. Hyperkalemia should be considered a differential for WCT in dogs.