Septic pericarditis caused by a migrating grass awn in a cat

Septic pericarditis and cardiac tamponade associated with migrating grass awn foreign bodies is reported rarely in companion animals. We report such a case in a previously healthy, 9-year-old, neutered female, indoor-outdoor, domestic long-hair cat who presented for acute tachypnea. Large volume pericardial effusion and pericardial tamponade was identified by thoracic-focused assessment with sonography. Following removal of 108 mL of purulent pericardial effusion by pericardiocentesis, the cat improved. Cytologic examination of pericardial fluid demonstrated septic, suppurative inflammation, Pasteurella sp. was cultured from pericardial effusion, and antibiotics were administered. Subsequent echocardiographic examination revealed large volume pericardial effusion, pericardial thickening, and a linear foreign body within the pericardial space. Whole-body computed tomography confirmed pericardial thickening, pericardial, and pleural effusion. A 16-mm long grass awn was identified within the pericardial space during thoracic exploratory surgery performed through a median sternotomy. Successful foreign body removal and subtotal pericardiectomy was accomplished. Histopathology of pericardial tissue disclosed chronic pericarditis with lymphoplasmacytic-to-pyogranulomatous inflammation, and transmural presence of grass awn foreign body. The cat responded to supportive therapy and was discharged 4 days postoperatively. When examined 3 weeks later, the cat appeared healthy with normal appetite. The cat remained healthy as of this writing, 487 days following surgery. To the author's knowledge, this is the first report in the cat of septic pericarditis and cardiac tamponade resulting from a migrating grass awn foreign body.

Giant pericardial-occupying compressive primary cardiac hemangiosarcoma in a cat

Hemangioarcoma in the cat is an infrequently diagnosed tumor, and cardiac involvement is rare. We report a previously healthy, 8-year-old, domestic shorthair cat with acute collapse associated with pericardial effusion and cardiac tamponade. Following pericardiocentesis and removal of 15 mL of fluid, the cat improved rapidly. A massive, space-occupying, intrapericardial tumor adhered to and compressing the right atrium and ventricle was detected by echocardiography. Approximately 5 weeks following initial presentation, bicavitary effusion and tachypnea developed, and the cat was euthanized. Necropsy revealed a giant intrapericardial mass adhered to and impinging upon the right heart. Histologic and immunohistochemical examination confirmed hemangiosarcoma with no gross or histologic evidence of metastasis. To the authors' knowledge, this is the first account of a pericardial-occupying, primary feline cardiac hemangiosarcoma resulting in compression of the right heart and cardiac tamponade, Further, this report describes novel clinicopathological relationships between radiographic and echocardiographic findings and gross and microscopic pathology.

Dilated cardiomyopathy in 151 Irish Wolfhounds: Characteristic clinical findings, life expectancy and causes of death

Dilated cardiomyopathy (DCM) is an important cause of morbidity in Irish Wolfhounds (IW), a breed also predisposed to neoplastic and orthopedic diseases that shorten life expectancy. The objective of this study was to investigate survival and causes of death in IW with DCM and to characterise the clinical findings of DCM over time. Data from cardiovascular examinations performed in 1591 IW, including echocardiography and electrocardiography, were retrospectively evaluated. IW with DCM on medical therapy with long term longitudinal follow-up were included in this study (n=151; 95 males, 56 females). Based on their clinical status at initial diagnosis, IW were classified into one of three groups: preclinical DCM with sinus rhythm (PC-DCM-SR, n=35), preclinical DCM with atrial fibrillation (PC-DCM-AF, n=87), and congestive heart failure with DCM and AF (CHF-DCM-AF, n=29). Survival data were analyzed using cumulative incidence functions, Kaplan-Meier and Cox regression. CHF was predominantly characterized by chylous pleural and mild pericardial effusions. Causes of death were cardiac (CD) in 73/151 and non-cardiac (non-CD) in 62/151; 16 dogs remained alive at study end. The majority of deaths in both preclinical DCM groups were non-CD (PC-DCM-AF=51.9% non-CD, 48.1% CD; PC-DCM-SR, 65.5% non-CD, 34.5% CD). In the CHF-DCM-AF group most dogs (89.6%) experienced a CD. Median survival of the CHF-DCM-AF group (7.3 months) was significantly shorter than in the PC-DCM-AF group (21.9 months) or PC-DCM-SR group (29.1 months, P=0.001). CHF-DCM-AF in IW was associated with reduced life expectancy and CD, while most IW with preclinical DCM died from non-cardiac causes.

Bartonella spp. as a Possible Cause or Cofactor of Feline Endomyocarditis-Left Ventricular Endocardial Fibrosis Complex

Endomyocarditis is a commonly detected post-mortem finding in domestic cats presenting for sudden onset cardiovascular death, yet the aetiology remains unresolved. Cats are documented reservoir hosts for Bartonella henselae, the infectious cause of cat scratch disease in man. Various Bartonella spp. have been associated with culture-negative endocarditis, myocarditis and sudden death in man and animals. We hypothesized that Bartonella spp. DNA could be amplified more often from the hearts of cats with feline endomyocarditis-left ventricular endocardial fibrosis (FEMC-LVEF) complex compared with cats with hypertrophic cardiomyopathy (HCM) or cats with grossly and microscopically unremarkable hearts (designated non-cardiac disease controls). Formalin-fixed and paraffin wax-embedded, cardiac tissues from 60 domestic and purebred cats aged 3 months to 18 years were examined, and histological features were recorded. Cardiac tissue sections were tested for Bartonella DNA using multiple 16-23S intergenic transcribed spacer region polymerase chain reaction (PCR) primer sets, including two Bartonella genera, a Bartonella koehlerae species-specific and a Bartonella vinsonii subsp. berkhoffii-specific assay, followed by DNA sequence confirmation of the species or genotype. Special precautions were taken to avoid DNA cross-contamination between tissues. Bartonella spp. DNA was amplified by PCR and sequenced from 18 of 36 cats (50%) with FEMC-LVEF and 1/12 (8.3%) cats with HCM. Bartonella spp. DNA was not amplified from any non-cardiac disease control hearts. Based on PCR/DNA sequencing, one Bartonella spp. was amplified from 10 cats, while the remaining eight were coinfected with more than one Bartonella spp. To our knowledge, this study represents the first documentation of B. vinsonii subsp. berkhoffii genotype I infection in cats (n = 11). Fluorescence in-situ hybridization testing facilitated visualization of Bartonella bacteria within the myocardium of four of seven PCR-positive FEMC-LVEF hearts. Collectively, these findings support the hypothesis that Bartonella spp. may play a primary role or act as a cofactor in the pathogenesis of FEMC-LVEF. Studies involving cats from other geographical regions and definitive demonstration of Bartonella spp. within regions of inflammation are needed to confirm an association between Bartonella spp. and FEMC-LVEF induced morbidity and mortality in cats.

Longitudinal Analysis of Quality of Life, Clinical, Radiographic, Echocardiographic, and Laboratory Variables in Dogs with Preclinical Myxomatous Mitral Valve Disease Receiving Pimobendan or Placebo: The EPIC Study

Background

Changes in clinical variables associated with the administration of pimobendan to dogs with preclinical myxomatous mitral valve disease (MMVD) and cardiomegaly have not been described.

Objectives

To investigate the effect of pimobendan on clinical variables and the relationship between a change in heart size and the time to congestive heart failure (CHF) or cardiac‐related death (CRD) in dogs with MMVD and cardiomegaly. To determine whether pimobendan‐treated dogs differ from dogs receiving placebo at onset of CHF.

Animals

Three hundred and fifty‐four dogs with MMVD and cardiomegaly.

Materials and Methods

Prospective, blinded study with dogs randomized (ratio 1:1) to pimobendan (0.4–0.6 mg/kg/d) or placebo. Clinical, laboratory, and heart‐size variables in both groups were measured and compared at different time points (day 35 and onset of CHF) and over the study duration. Relationships between short‐term changes in echocardiographic variables and time to CHF or CRD were explored.

Results

At day 35, heart size had reduced in the pimobendan group: median change in (Δ) LVIDDN −0.06 (IQR: −0.15 to +0.02), P < 0.0001, and LA:Ao −0.08 (IQR: −0.23 to +0.03), P < 0.0001. Reduction in heart size was associated with increased time to CHF or CRD. Hazard ratio for a 0.1 increase in ΔLVIDDN was 1.26, P = 0.0003. Hazard ratio for a 0.1 increase in ΔLA:Ao was 1.14, P = 0.0002. At onset of CHF, groups were similar.

Conclusions and Clinical Importance

Pimobendan treatment reduces heart size. Reduced heart size is associated with improved outcome. At the onset of CHF, dogs treated with pimobendan were indistinguishable from those receiving placebo.

Naturally Occurring Biventricular Noncompaction in an Adult Domestic Cat

A definitively diagnosed case of left ventricular noncompaction (LVNC) has not been previously reported in a non‐human species. We describe a Maine Coon cross cat with echocardiographically and pathologically documented LVNC. The cat was from a research colony and was heterozygous for the cardiac myosin binding protein C mutation associated with hypertrophic cardiomyopathy (HCM) in Maine Coon cats (A31P). The cat had had echocardiographic examinations performed every 6 months until 6 years of age at which time the cat died of an unrelated cause. Echocardiographic findings consistent with LVNC (moth‐eaten appearance to the inner wall of the mid‐ to apical region of the left ventricle (LV) in cross section and trabeculations of the inner LV wall that communicated with the LV chamber) first were identified at 2 years of age. At necropsy, pathologic findings of LVNC were verified and included the presence of noncompacted myocardium that consisted of endothelial‐lined trabeculations and sinusoids that constituted more than half of the inner part of the LV wall. The right ventricular (RV) wall also was affected. Histopathology identified myofiber disarray, which is characteristic of HCM, although heart weight was normal and LV wall thickness was not increased.

Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study-A Randomized Clinical Trial

Background

Pimobendan is effective in treatment of dogs with congestive heart failure (CHF) secondary to myxomatous mitral valve disease (MMVD). Its effect on dogs before the onset of CHF is unknown.

Hypothesis/Objectives

Administration of pimobendan (0.4–0.6 mg/kg/d in divided doses) to dogs with increased heart size secondary to preclinical MMVD, not receiving other cardiovascular medications, will delay the onset of signs of CHF, cardiac‐related death, or euthanasia.

Animals

360 client‐owned dogs with MMVD with left atrial‐to‐aortic ratio ≥1.6, normalized left ventricular internal diameter in diastole ≥1.7, and vertebral heart sum >10.5.

Methods

Prospective, randomized, placebo‐controlled, blinded, multicenter clinical trial. Primary outcome variable was time to a composite of the onset of CHF, cardiac‐related death, or euthanasia.

Results

Median time to primary endpoint was 1228 days (95% CI: 856–NA) in the pimobendan group and 766 days (95% CI: 667–875) in the placebo group (P = .0038). Hazard ratio for the pimobendan group was 0.64 (95% CI: 0.47–0.87) compared with the placebo group. The benefit persisted after adjustment for other variables. Adverse events were not different between treatment groups. Dogs in the pimobendan group lived longer (median survival time was 1059 days (95% CI: 952–NA) in the pimobendan group and 902 days (95% CI: 747–1061) in the placebo group) (P = .012).

Conclusions and Clinical Importance

Administration of pimobendan to dogs with MMVD and echocardiographic and radiographic evidence of cardiomegaly results in prolongation of preclinical period and is safe and well tolerated. Prolongation of preclinical period by approximately 15 months represents substantial clinical benefit.

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

Background

Dilated 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.

Objectives

Compare 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.

Animals

Seventy‐five client‐owned IW dogs.

Methods

Irish 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.

Results

Sixty‐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 Importance

In 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.

Clinical Features and Outcome of Dogs with Epiglottic Retroversion With or Without Surgical Treatment: 24 Cases

BACKGROUND

Published information describing the clinical features and outcome for dogs with epiglottic retroversion (ER) is limited.

HYPOTHESIS/OBJECTIVES

To describe clinical features, comorbidities, outcome of surgical versus medical treatment and long-term follow-up for dogs with ER. We hypothesized that dogs with ER would have upper airway comorbidities and that surgical management (epiglottopexy or subtotal epiglottectomy) would improve long-term outcome compared to medical management alone.

ANIMALS

Twenty-four client-owned dogs.

METHODS

Retrospective review of medical records to identify dogs with ER that underwent surgical or medical management of ER.

RESULTS

Dogs with ER commonly were middle-aged to older, small breed, spayed females with body condition score (BCS) ≥6/9. Stridor and dyspnea were the most common presenting signs. Concurrent or historical upper airway disorders were documented in 79.1% of cases. At last evaluation, 52.6% of dogs that underwent surgical management, and 60% of dogs that received medical management alone, had decreased severity of presenting clinical signs. In dogs that underwent surgical management for ER, the incidence of respiratory crisis decreased from 62.5% before surgery to 25% after surgical treatment. The overall calculated Kaplan-Meier median survival time was 875 days.

CONCLUSION AND CLINICAL IMPORTANCE

Our study indicated that a long-term survival of at least 2 years can be expected in dogs diagnosed with epiglottic retroversion. The necessity of surgical management cannot be determined based on this data, but dogs with no concurrent upper airway disorders may benefit from a permanent epiglottopexy to alleviate negative inspiratory pressures.

Relationship of plasma N-terminal pro-brain natriuretic peptide concentrations to heart failure classification and cause of respiratory distress in dogs using a 2nd generation ELISA assay

Background

Cardiac biomarkers provide objective data that augments clinical assessment of heart disease (HD).

Hypothesis/Objectives

Determine the utility of plasma N‐terminal pro‐brain natriuretic peptide concentration [NT‐proBNP] measured by a 2nd generation canine ELISA assay to discriminate cardiac from noncardiac respiratory distress and evaluate HD severity.

Animals

Client‐owned dogs (n = 291).

Methods

Multicenter, cross‐sectional, prospective investigation. Medical history, physical examination, echocardiography, and thoracic radiography classified 113 asymptomatic dogs (group 1, n = 39 without HD; group 2, n = 74 with HD), and 178 with respiratory distress (group 3, n = 104 respiratory disease, either with or without concurrent HD; group 4, n = 74 with congestive heart failure [CHF]). HD severity was graded using International Small Animal Cardiac Health Council (ISACHC) and ACVIM Consensus (ACVIM‐HD) schemes without knowledge of [NT‐proBNP] results. Receiver‐operating characteristic curve analysis assessed the capacity of [NT‐proBNP] to discriminate between dogs with cardiac and noncardiac respiratory distress. Multivariate general linear models containing key clinical variables tested associations between [NT‐proBNP] and HD severity.

Results

Plasma [NT‐proBNP] (median; IQR) was higher in CHF dogs (5,110; 2,769–8,466 pmol/L) compared to those with noncardiac respiratory distress (1,287; 672–2,704 pmol/L; P < .0001). A cut‐off >2,447 pmol/L discriminated CHF from noncardiac respiratory distress (81.1% sensitivity; 73.1% specificity; area under curve, 0.84). A multivariate model comprising left atrial to aortic ratio, heart rate, left ventricular diameter, end‐systole, and ACVIM‐HD scheme most accurately associated average plasma [NT‐proBNP] with HD severity.

Conclusions and Clinical Importance

Plasma [NT‐proBNP] was useful for discriminating CHF from noncardiac respiratory distress. Average plasma [NT‐BNP] increased significantly as a function of HD severity using the ACVIM‐HD classification scheme.

Change in β-catenin localization suggests involvement of the canonical Wnt pathway in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy

Background

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited myocardial disease with high prevalence in the Boxer dog population. It is characterized by replacement of the myocardium with fatty or fibro‐fatty tissue. Several mechanisms for the development of ARVC have been suggested, including dysfunction of the canonical Wnt pathway, which is linked to many cellular functions, including growth and differentiation of adipocytes.

Hypothesis

Wnt pathway dysfunction is involved in the development of ARVC in the Boxer as evidenced by mislocalization of β‐catenin, an integral Wnt pathway modulator, and striatin, a known Wnt pathway component.

Animals

Five dogs without ARVC and 15 Boxers with ARVC were identified by 24‐hour Holter monitoring and histopathologic examination of the heart.

Methods

Right ventricular samples were collected and examined using confocal microscopy, Western blots, and quantitative (q) PCR.

Results

Confocal microscopy indicated that β‐catenin localized at sites of cell‐to‐cell apposition, and striatin localized in a diffuse intracellular pattern in hearts without ARVC. In hearts affected with ARVC, both β‐catenin and striatin were colocalized with the endoplasmic reticulum (ER) marker calreticulin. Western blots indentified a 50% increase in the amount of β‐catenin in ARVC samples. No change in β catenin mRNA was detected using qPCR.

Conclusions

Our data suggest that trafficking of Wnt pathway proteins from the ER to their proper location within the cell is inhibited in Boxers with ARVC. These results suggest that disturbances in the Wnt pathway may play a role in the development of ARVC in the Boxer.

Effect of NT-pro-BNP assay on accuracy and confidence of general practitioners in diagnosing heart failure or respiratory disease in cats with respiratory signs

BACKGROUND

N-terminal pro-B-type natriuretic peptide (NT-proBNP) can distinguish congestive heart failure (CHF) from primary respiratory disease in cats with respiratory signs with approximately 90% diagnostic accuracy, but the additive benefit of NT-proBNP to improve the diagnosis obtained from conventional testing in individual cases remains unknown.

HYPOTHESIS

NT-proBNP will improve the diagnostic accuracy and confidence of general practice veterinarians in assessing cats with respiratory signs.

ANIMALS

Ten cats with respiratory signs.

METHODS

History, physical examination, thoracic radiographs, electrocardiogram (ECG), and biochemical analysis of 10 cats presented to the University of Pennsylvania or Tufts University with a history of respiratory signs were evaluated by 50 general practice veterinarians using an online survey tool. Participants were asked to provide (1) diagnosis of CHF or primary respiratory disease, and (2) level of confidence in their diagnosis (1, lowest to 10, highest) before and after disclosure of NT-proBNP results. Diagnoses (CHF, n = 5; primary respiratory, n = 5) were compared to the gold standard defined as consensus opinion of 3 board-certified cardiologists blinded to the NT-proBNP results.

RESULTS

Overall correctness of the practitioners was 69.2%, and significantly increased after practitioners were provided NT-proBNP results (87.0%, P = .0039). Median practitioner confidence before NT-proBNP disclosure was 6 (IQR, 5-8) and significantly increased after disclosure (8; IQR, 6-10; P = .0039).

CONCLUSIONS

These data indicate a relatively low accuracy and level of confidence in the diagnosis of feline respiratory signs. Use of NT-proBNP assay in conjunction with conventional evaluation by general practitioners significantly improved their diagnostic accuracy and confidence.

Comparison of polymerase chain reaction with bacterial 16s primers to blood culture to identify bacteremia in dogs with suspected bacterial endocarditis

BACKGROUND

Identification of the bacterial organism in dogs with endocarditis is challenging. Human studies have reported the utility of the polymerase chain reaction (PCR) to amplify and identify bacterial nucleic acid from infected valvular tissue and blood.

HYPOTHESIS/OBJECTIVES

We hypothesized that PCR using primers designed to amplify the bacterial 16s gene would identify circulating bacteria in dogs with suspected bacterial endocarditis more consistently than standard blood culture techniques.

ANIMALS

Eighteen dogs with suspected bacterial endocarditis based upon clinical and echocardiographic findings. Fifteen clinically normal dogs served as negative controls.

METHODS

Prospective study of dogs evaluated for suspect endocarditis at 6 veterinary hospitals. A blood sample was drawn from all dogs and evaluated with both a single-sample PCR and standard 3-sample blood culture techniques.

RESULTS

Blood culture identified noncontaminant bacteria in 6/18 study animals (33%) and 1 control dog; PCR identified noncontaminant bacteria in 7/18 study animals (39%). There were no study animals in which the 2 tests identified different bacteria (κ = 1.0). However, bacteria were identified by both techniques in only 2/18 study animals. When results from both PCR and blood culture were considered together, a noncontaminant bacterial organism was identified in 11/18 study animals (61%).

CONCLUSION AND CLINICAL IMPORTANCE

The results of this study suggest that although single sample PCR with 16s primers was not more sensitive than blood culture for detection of bacteremia in dogs with suspect endocarditis, performing both techniques simultaneously did increase the likelihood of identification of bacteria in blood.

Complex segregation analysis of dilated cardiomyopathy (DCM) in Irish wolfhounds

The objective of the present study was to analyse the mode of inheritance for dilated cardiomyopathy (DCM) in Irish wolfhounds using regressive logistic models by testing for mechanisms of genetic transmission. Insights from this spontaneous animal model should aid importantly in understanding basic pathogenic mechanisms with regard to genetics and molecular biology of DCM in humans. Moreover, a procedure for the simultaneous prediction of breeding values and the estimation of genotype probabilities for DCM is expected to markedly improve breeding programmes. Results of cardiovascular examinations of 1018 dogs carried out between 1987 and 2003 by one veterinarian were analysed. Data of 878 dogs from 531 litters in 147 different kennels were used for complex segregation analyses. Pedigree information was available for more than 15 generations. Male dogs were affected significantly more often by DCM than female dogs. The segregation analysis showed that among all other tested models a mixed monogenic-polygenic model including a sex-dependent allele effect best explained the segregation of affected animals in the pedigrees. A pure monogenic inheritance of DCM could be significantly rejected in favour of the major gene and most general model. The gene action of the major gene was significantly different between female and male dogs.

Spontaneously occurring arrhythmogenic right ventricular cardiomyopathy in the domestic cat: A new animal model similar to the human disease

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a primary myocardial disease of incompletely resolved pathogenesis and is a largely unappreciated cause of sudden death in the young.

METHODS AND RESULTS

Clinical features of 12 domestic cats with ARVC (7 male; 1 to 20 years old, mean 7.3+/-5.2 years) were right-sided congestive heart failure (n=8), supraventricular tachyarrhythmias (n=5), ventricular tachycardia (n=3), polymorphic ventricular arrhythmias (n=6), and right bundle-branch block (n=5). ARVC was suspected in all 8 cats examined with echocardiography by marked enlargement of the right ventricle (RV) and right atrium and tricuspid regurgitation. Eight died of cardiovascular disease and 4 died of noncardiac conditions. At autopsy, hearts of ARVC cats were characterized grossly by moderate-to-severe RV cavity enlargement and wall thinning (n=12) and apical aneurysm formation (n=6). Histology demonstrated pronounced RV lesions in all 12 ARVC cats, including marked myocardial injury (myocyte death and atrophy) and repair (fibrous and/or fatty replacement). Injury and repair were also evident in the left ventricle (LV) in 10 cats, and 2 had involvement of both atria. Myocarditis was present in 10 of the 12 ARVC cats. Apoptosis was detected in 9 ARVC cats (mean apoptotic index, 28+/-23% RV, 21+/-19% LV, and 17+/-15% ventricular septum) but not in controls.

CONCLUSIONS

In the common domestic cat, we identified a clinically relevant cardiomyopathy that closely mimics ARVC in humans. This unique feline model of human disease will be relevant to defining pathogenesis and investigating mechanisms responsible for disease progression in ARVC.

Molecular screening by polymerase chain reaction detects panleukopenia virus DNA in formalin-fixed hearts from cats with idiopathic cardiomyopathy and myocarditis

Viral myocarditis has been suggested as an etiology for cardiomyopathy in several mammalian species. Myocarditis and idiopathic cardiomyopathy have been reported in the domestic cat, although a viral etiology has not been demonstrated. Because of the continuing interest in the potential relationship between viral myocarditis and cardiomyopathy, we evaluated hearts from cats with spontaneous, idiopathic cardiomyopathy for viral genomic material within myocytes by polymerase chain reaction, and for the presence of myocarditis by light microscopy. Thirty-one (31) formalin-fixed hearts from domestic cats who died of idiopathic cardiomyopathy were randomly selected from pathology archives. Seventeen (17) formalin-fixed hearts from healthy cats were similarly selected as normal controls. The polymerase chain reaction (PCR) was used to evaluate myocardial tissue for the presence of viral genome from feline panleukopenia virus, herpes virus, calici virus, and corona virus. Hearts were examined using light microscopy for histologic evidence of myocarditis according to the Dallas criteria. Panleukopenia virus was identified by PCR in 10 of 31 cats with cardiomyopathy but in none of the controls. Neither cardiomyopathic or control cats tested positive by PCR for herpes virus, calici virus, and corona virus. Myocarditis was detected by histologic examination in 18 of 31 cardiomyopathic cats and in none of 17 control cats. Myocarditis and or feline panleukopenia virus genome was detected in felines with idiopathic hypertrophic, dilated, and restrictive cardiomyopathy, suggesting a possible role of viral infection and inflammation in the pathogenesis of cardiomyopathy in this species.

Electrocardiographic and radiographic changes in cats with hyperthyroidism: comparison of populations evaluated during 1992-1993 vs. 1979-1982

Cardiovascular manifestations of feline hyperthyroidism were compared in two populations of cats diagnosed at The Animal Medical Center from 1992 to 1993 (n=202) and 1979 to 1982 (n = 131). The prevalence of sinus tachycardia and increased R-wave voltage in lead II were both lower in the 1993 population compared with the 1982 population (p less than 0.001). A low frequency of atrial and ventricular arrhythmias and intraventricular conduction abnormalities were recorded in both populations. No significant differences between populations were recorded in the number of cats with mild, moderate, and severe cardiomegaly seen on thoracic radiographs. The percentage of cats in which radiographs were deemed clinically necessary based upon history and clinical examination was 25% of the 1993 population, compared with 63% of the 1982 population. The number of cats with radiographic evidence of congestive heart failure was 8% in 1993 compared with 20% in 1982, although this difference was not statistically significant. In conclusion, the incidence and severity of certain thyrotoxic cardiovascular manifestations were reduced in cats diagnosed between 1992 and 1993 compared with those diagnosed between 1979 and 1982.

Fibrosis, myocyte degeneration and heart failure in chronic experimental aortic regurgitation

Myocardial fibrosis and myocyte degeneration have been reported in patients with chronic aortic regurgitation (AR), and may be related to the pathophysiology of congestive heart failure (CHF) in this disease. To define the relationship between myocardial histopathologic variations and CHF in chronic AR, we performed gross and microscopic evaluations of postmortem tissue from a rabbit model of chronic AR manifesting left ventricular (LV) responses to AR similar to those in humans. Moderate-to-severe chronic AR (echocardiographic regurgitant fraction = 52 +/- 13%) was induced by closed-chest aortic valve perforation in 11 New Zealand White rabbits; 5 control rabbits were sham operated. Six of the 11 AR rabbits died 1.5 +/- 0.8 years (range 0.6-2.8 years) after AR induction; all 6 had gross and histologic anatomic evidence of CHF at necropsy. The remaining 5 AR rabbits survived until sacrifice at 2.9 +/- 0.1 years of AR; none had pathologic evidence of CHF. Cardiac hypertrophy and the extent of LV fibrosis and myocyte necrosis all were greatest among the 6 AR CHF rabbits. No inflammatory response was apparent in any animal. Moderate-to-severe chronic experimental AR frequently results in CHF which is strongly associated with myocardial fibrosis and necrosis, without evidence of inflammation. These histopathologic variations may be pathophysiologically related to CHF development.

Echocardiographic assessment of spontaneously occurring feline hypertrophic cardiomyopathy. An animal model of human disease

BACKGROUND

Necropsy studies in domestic cats have suggested the occurrence of a primary cardiac disease resembling hypertrophic cardiomyopathy (HCM) in humans. We used two-dimensional echocardiography to define morphological and functional features of HCM during life in 46 domestic cats evaluated in a subspecialty veterinary clinic. Cats were 8 months to 14 years old (mean, 6 years).

METHODS AND RESULTS

During the follow-up period of as long as 49 months, 18 cats died (or were euthanatized) due to congestive heart failure, peripheral embolization, or both, and 3 other cats experienced out-of-hospital sudden, unexpected death. Echocardiography showed a small left ventricular cavity, associated with a variety of patterns of hypertrophy. Wall thickening was most often diffuse (involving ventricular septum and free wall) in 31 cats (67%) and segmental in 15 (33%), including 12 with thickening confined to anterior septum; wall thickening was judged to be asymmetrical in 42 and symmetrical (concentric) in 4. In 30 cats (65%), marked mitral valve systolic anterior motion produced dynamic obstruction to left ventricular outflow (Doppler estimated gradients, 25 to 110 mm Hg). Compared with survivors, cats with HCM that died with heart failure had greater left ventricular thickness (8.1 +/- 1.5 versus 7.3 +/- 0.9 mm; P < .05) and larger left atria (20.1 +/- 4.6 versus 16.8 +/- 3.4 mm; P = .01) and more often had the nonobstructive form (89% versus 48%; P < .01).

CONCLUSIONS

A spontaneously occurring disease of domestic cats was identified by echocardiography and was similar in its phenotypic expression to HCM in humans; it was characterized by unexplained left ventricular hypertrophy in a variety of patterns with or without evidence of outflow obstruction. Unfavorable prognosis was associated with greater magnitude of hypertrophy and absence of outflow obstruction. Feline HCM may prove to be a valuable animal model of the human disease.

Effects of electrocardiograph frequency filters on P-QRS-T amplitudes of the feline electrocardiogram

OBJECTIVE--To determine whether standard manual frequency filters in the ON and OFF settings affected P-QRS-T voltages, discover whether recorded P-QRS-T voltages vary between commercial electrocardiographs, assess effects of frequency filters on base-line artifact, and evaluate ECG frequency content by high-fidelity recordings subjected to digital filters with variable frequencies. DESIGN--Sequential 10-lead ECG were recorded in 30 cats, using 3 commercial electrocardiographs to assess effects of manual frequency filters on the P-QRS-T wave forms. Three clinically normal cats were evaluated for ECG frequency content. ANIMALS--Thirty cats (13 with hypertrophic cardiomyopathy; 4 with restrictive cardiomyopathy; 3 hyperthyroid; 1 with ventricular septal defect; 1 with aortic stenosis; and 8 with no detectable cardiovascular disease). Three additional clinically normal cats were studied for effects of frequency filters on the ECG frequency content. PROCEDURES--Ten-lead ECG were recorded on each cat by use of 3 commercial electrocardiographs sequentially. For each machine, a recording was made with manual filters ON, immediately followed by a recording with manual filters OFF. High-fidelity lead-II ECG recordings were made with filters set with their rolloff frequency at 0.1 Hz and 3.0 kHz; output voltage (0.2 mV/V) was fed to an analog-to-digital converter, then to attendant software, which sampled the signal at 6 kHz with a 12-bit sampler, and were digitally filtered at various corner frequencies. RESULTS--Voltages recorded by all 3 electrocardiographs were greatest when filters were OFF (most prominent on R- and S-wave voltages). In all recorded leads, R-wave voltage was significantly greater when filters were OFF than ON. Comparison of voltages indicated significant (P < 0.05) differences between R-wave voltages recorded in all leads with manual filters ON, but not with filters OFF. With filters ON, each electrocardiograph produced a smaller percentage of recordings with moderate to severe baseline artifact than with filters OFF. R-Wave amplitudes of high-fidelity lead-II ECG were significantly decreased with digital filters set at corner frequencies < 150 Hz. CONCLUSIONS--Significant (P < 0.05) voltage attenuation was recorded by each of the 3 commercial electrocardiographs when frequency filters were ON, compared with OFF. Comparison of waveform voltages among electrocardiographs with filters ON indicated significant variation in R-wave amplitudes in all leads. With manual filters ON, each electrocardiograph recorded a smaller percentage of recordings with baseline artifact than with filters OFF. Substantial frequency components > or = 150 Hz are present in the feline ECG waveform. Thus, filters with frequencies < 150 Hz markedly attenuate the feline R wave. CLINICAL RELEVANCE--Attenuation of feline ECG signals occurs with use of commercial electrocardiographs and varies greatly between manufacturers. This is attributable largely to internal manual frequency filters. These consequences may be important when applying standard feline reference values or when equivocal voltage measurements are recorded.

Plasma taurine concentrations in normal dogs and in dogs with heart disease

Plasma taurine concentrations were determined in 76 dogs with dilated cardiomyopathy (DCM), 28 dogs with acquired valvular disease (AVD), and 47 normal (control) dogs. The data were collected at 2 referral centers, The Animal Medical Center, New York, NY (AMC), and the University of California, Davis (UCD), and the studies were conducted independently. Different anticoagulants (sodium citrate at AMC and lithium heparin at UCD) were used to collect the plasma samples. Paired analysis of samples showed a significant difference in plasma taurine concentrations, depending on the anticoagulant used. Consequently, results from each clinic were analyzed separately. Plasma taurine concentrations were significantly higher in dogs with AVD (median, 133 nmol/mL; range, 25 to 229 nmol/mL) than in control dogs (median, 63 nmol/mL; range 44 to 224 nmol/mL) and dogs with DCM (median, 72 nmol/mL; range, 1 to 247 nmol/mL) at AMC (P < .001). The number of dogs with AVD at UCD was too small to draw meaningful conclusions. At UCD, the median plasma taurine concentration was 98 nmol/mL (range, 28-169 nmol/mL) in dogs with AVD, 75 nmol/mL (range, 0.1-184 nmol/mL) in dogs with DCM, and 88 nmol/mL (range 52-180 nmol/mL) in control dogs. There were no significant differences in plasma taurine concentrations between dogs with DCM and the control dogs at either hospital. Congestive heart failure and administration of cardiac medication had no significant effect on plasma taurine concentrations. Plasma taurine concentration was low (< 25 nmol/mL) in 17% (13/76) of the dogs with DCM. Seven of the 13 dogs with low plasma taurine concentrations were Cocker Spaniels or Golden Retrievers.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventricular arrhythmias in dogs undergoing splenectomy: a prospective study

Fifty dogs undergoing splenectomy for splenic masses (n = 40), torsion of the splenic pedicle (n = 5), and immune-mediated disease (n = 5) were evaluated preoperatively and and postoperatively for ventricular arrhythmias and the relationship between ventricular arrhythmia splenic disease. The ability of 1-minute electrocardiograms recorded every 6 hours (ECGs/q6hr) to detect ventricular arrhythmia was compared with continuous 48-hour Holter monitoring. Based on continuous Holter monitoring, splenectomized dogs had a high incidence (22 of 50) of rapid ventricular tachycardia. The incidence of rapid ventricular tachycardia was significantly higher in dogs with ruptured splenic masses (16 of 23) than without rupture (1 of 17) (P < .001). When the results of ECG/q6hr were compared with the results of continuous Holter monitoring ECG/q6hr was normal in 29% (4 of 14) of dogs with rapid ventricular tachycardia at > 3,000 ventricular extrasystoles (VE)/hr; 50% (4 of 8) of dogs with rapid ventricular tachycardia at 1,000 to 3,000 VE/hr and 100% (6 of 6) of dogs with 10 to 300 VE/hr without rapid ventricular tachycardia. Although dogs undergoing splenectomy had a high incidence of ventricular arrhythmias, one-minute ECGs/q6h were unreliable for detection of ventricular arrhythmias even when high-frequency extrasystoles occurred.

Comparison of taurine, alpha-tocopherol, retinol, selenium, and total triglycerides and cholesterol concentrations in cats with cardiac disease and in healthy cats

Epidemiologic relations were evaluated between plasma concentrations of nutrients and cardiovascular diseases. A total of 220 cats were assessed: 144 cats with noninduced acquired heart disease and 76 clinically normal cats. Plasma was assayed for taurine, alpha-tocopherol, selenium, retinol, and total cholesterol and triglycerides concentrations. Cardiovascular disease groups included dilated cardiomyopathy (n = 53), left ventricular hypertrophy (n = 28), hyperthyroidism (n = 11), and uncertain classification (n = 52). In cats with dilated cardiomyopathy, mean plasma taurine concentration was the lowest of that in cats of any group, being only 38% of the value in healthy cats; females had less than half the mean value of males. Tocopherol concentration was 20% lower than normal, and retinol concentration was 40% higher than normal. Total cholesterol concentration was 36% lower than normal. Triglycerides concentration was higher in these cats than in any other group--twice the value recorded in healthy cats and 67% higher than that in hyperthyroid cats. In cats with hypertrophic cardiomyopathy, almost 15% had mean plasma taurine concentration < 30 mumol/L. Retinol concentration was 15% higher, and triglycerides concentration was 54% higher than normal. Approximately 27% of hyperthyroid cats had mildly decreased plasma taurine concentration. Hyperthyroid cats had the lowest tocopherol and cholesterol values; both were at least 30% lower than normal. Retinol concentration was 30% higher than normal. Approximately 14% of cats with uncertain classification had mildly decreased plasma taurine concentration. Plasma retinol and triglycerides concentrations were higher than normal in 25 and 38% of these cats, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical, echocardiographic, and Doppler imaging characteristics of mitral valve stenosis in two dogs

Mitral stenosis was diagnosed noninvasively by echocardiography and Doppler imaging in 2 Bull Terriers. Two-dimensional echocardiography revealed severe atrial and moderate left ventricular dilatation; severely reduced mitral valve opening excursion; doming of the cranial mitral valve leaflet into the left ventricle during diastole; thickened, nodular cranial mitral valve leaflets; and reduced mitral valve orifice. M-mode echocardiographic findings additionally indicated greatly diminished mitral valve E to F slope and abnormal caudal mitral valve leaflet motion. Color flow Doppler imaging revealed bright bursts of color with aliasing originating from the stenotic mitral valve orifice, extending into the left atrium during systole, and into the left atrium during diastole. Spectral Doppler recordings revealed transvalvular mitral valve gradients and prolonged pressure half-times. Necropsy performed on 1 dog revealed extremely thickened, nodular, and stiff mitral valves with short, thickened, and fused chordae tendineae. The diagnosis of mitral valve stenosis was easily facilitated with diagnostic ultrasonography.

Doxorubicin-induced cardiotoxicosis. Clinical features in 32 dogs

Clinical cardiac abnormalities developed in 32 of 175 dogs that had various malignancies and were treated with doxorubicin: 31 dogs had electrocardiographic abnormalities including arrhythmias and nonspecific alterations in the R wave, ST segment, or QRS duration and 7 dogs had congestive heart failure. All seven dogs that had congestive heart failure died within 90 days. At necropsy, 13 of 32 affected dogs had noninflammatory myocardial degeneration, myocytolysis, vacuolation, and/or fibrosis and there was intramural coronary arteriosclerosis in all 13. Five dogs with lymphosarcoma were in complete clinical remission when they died of doxorubicin-induced cardiomyopathy, but the overall survival times of the lymphosarcoma subset was nevertheless longer than in previous studies. The clinical use of doxorubicin in the dog can cause cardiotoxicosis but the therapeutic benefit appears to outweigh risks in most dogs.

Myocardial taurine concentrations in cats with cardiac disease and in healthy cats fed taurine-modified diets

Myocardial taurine concentrations were measured in cats with cardiac disease and in healthy cats fed diets with various concentrations of taurine. Group 1 was composed of 26 cats with 3 categories of naturally developing cardiac disease: dilatative cardiomyopathy (group 1A), 10 cats; hypertrophic cardiomyopathy (group 1B), 9 cats; and volume overload (group 1C), 7 cats. These cats had been fed various commercial diets. Group 2 was composed of 40 healthy cats that had been fed diets varying in taurine concentration (0 to 1% taurine) for at least 2 years. Mean myocardial taurine concentrations did not differ significantly between group-1 cats with dilatative cardiomyopathy and those with hypertrophic cardiomyopathy or volume overload. Cats in group 1A had a mean myocardial taurine concentration 3 times higher than healthy cats fed a taurine-free diet (P less than 0.002). Mean myocardial taurine concentrations did not differ significantly between group-1A cats and healthy cats fed a diet containing 0.02% taurine; group-1A cats had significantly lower mean myocardial taurine concentrations than did healthy cats fed a synthetic diet containing 0.05 or 1.0% taurine (P less than 0.001). Acute oral administration of taurine in 5 group-1A cats appeared to increase mean myocardial taurine concentrations, compared with similar cats not given taurine during treatment for cardiac failure. In group-2 cats, mean myocardial taurine concentrations increased directly with percentage of dietary taurine.

Techniques and complications of pacemaker implantation in four cats

Pacemakers were successfully implanted in 4 adult and geriatric cats with bradycardia and associated signs. Various implantation techniques were used. Complications developed in 3 of the cats, generally more severe in 2 of the 3 cats in which thoracotomy and celiotomy were performed than in the cat in which a transvenous endocardial pacing technique was used. After surgery, pacemaker functions were reprogrammed noninvasively in 2 cats. All 4 cats survived without syncope for a mean of 33.1 months after surgery.

Evidence for or against efficacy of beta-blockers and aspirin for management of feline cardiomyopathies

Feline myocardial diseases today are largely represented by disorders involving LV hypertrophy. They may be attended by arrhythmias, congestive heart failure, systemic hypertension, thromboembolic complications, and sudden death. These structural myocardial disorders and their hemodynamic and electrocardiographic derangements may cause or result in variable degrees of diastolic dysfunction. Propranolol and aspirin represent two agents commonly employed to treat feline cardiomyopathies for more than 15 years. Nevertheless, clinical data describing their effect on morbidity and mortality are lacking. It is likely that propranolol administered at moderate to high doses effects favorable responses in some cats with clinical signs attributable to severe hypertrophy, outflow obstruction, or tachyarrhythmias. It is unknown whether clinical improvements are due to direct myocardial effects or (more likely) secondary responses to a beta-adrenergic blockade reduction in heart rate or contractility. Personal experience also indicates that high numbers of cats have received the drug for many years in combination with other therapies (especially furosemide) and remain in a compensated state of heart failure without untoward drug effects. On the other hand, many cardiomyopathic cats experience heart failure, arrhythmias, and death despite treatment with beta-blocking agents. Feline thromboembolism is a devastating complication of cardiomyopathic disorders. Until or unless the primary cause(s) of current diseases is elucidated to promote disease reversal, factors responsible for thrombus formation will accompany the heart diseases, protected from effective management. It appears unlikely that aspirin as currently recommended produces any obvious benefit in treating or preventing thromboembolism. Modifications of therapeutic protocols prescribing these frequently used drugs await well-constructed clinical trials evaluating their efficacy with respect to cardiovascular morbidity and mortality.

Plasma taurine concentrations and M-mode echocardiographic measures in healthy cats and in cats with dilated cardiomyopathy

M-mode echocardiography was completed and plasma taurine concentrations were determined in 79 healthy cats and 77 cats with dilated cardiomyopathy (DCM). In healthy cats, a relationship was not observed between plasma taurine concentrations and any M-mode echocardiographic measurement. End-systolic and end-diastolic cardiac chamber dimensions were larger; wall thickness measures were smaller; and calculations of fractional shortening were less in cats with DCM than in healthy cats. Plasma taurine concentrations less than 30 nmol/mL were detected in 7/79 healthy cats and in 52/77 cats with DCM. Of the 52 cats with DCM and an initial plasma taurine concentration less than 30 nmol/mL, 23 died or were euthanized during the first post-treatment week, 7 were lost to further study, and 22 improved after taurine supplementation. Of the 25 cats with DCM and an initial plasma taurine concentration greater than or equal to 30 nmol/mL, 9 died or were euthanatized during the first post-treatment week, and 9 were lost to further study. Two cats did not improve, of which one died and one was euthanatized 4 to 8 weeks after initiation of taurine supplementation. Five cats with a plasma taurine concentration greater than or equal to 30 nmol/mL improved after taurine supplementation. Myocardial function subsequently deteriorated in three of these cats. Two of the three cats had signs of congestive heart failure redevelop.

Critical care cardiology

Management of the critical care cardiology patient often requires a rapid, accurate diagnostic and therapeutic strategy. A wide range of cardiovascular drugs is available for treatment of shock, congestive heart failure, and arrhythmias.

Echocardiographic findings in 103 cats with hyperthyroidism

Using M-mode echocardiography, cardiac abnormalities were studied in 103 cats with untreated hyperthyroidism. In addition, follow-up echocardiography was performed on 24 of these cats to assess the long-term (4 to 21 months) effect of treatment (thyroidectomy or radioiodine) on thyrotoxic cardiac disease. The most common echocardiographic abnormality in the 103 untreated hyperthyroid cats was hypertrophy of the left ventricular caudal wall (71.9%). Hypertrophy of the interventricular septum also was documented in 39.8% of the 103 cats. Other abnormalities included high values for left atrial diameter (70.0%), aortic root diameter (18.5%), and left ventricular diameter at end diastole (45.6%). In some of these cats, indices of contractility were enhanced; in 21.4% and 14.6% of the cats, values for shortening fraction and velocity of circumferential fiber shortening, respectively, were greater than those values measured in clinically normal cats. After treatment of the hyperthyroidism, left ventricular hypertrophy resolved or improved in many of the cats, as indicated by decreases in left ventricular caudal wall and interventricular septum thicknesses. Hyperdynamic wall motion resolved in all cats after treatment, as evidenced by consistent decreases in shortening fraction and velocity of circumferential fiber shortening. Despite these improvements, some cats had one or more persistently abnormal echocardiographic values after treatment. These results suggested that in cats, hyperthyroidism commonly is associated with largely reversible cardiomyopathy. In those cats in which cardiomyopathy persists or worsens after treatment, underlying primary cardiomyopathy or thyroid hormone-induced cardiac structural damage may exist.

Acute mitral regurgitation with papillary muscle rupture in a dog

Papillary muscle rupture is uncommon in the dog. Two-dimensional echocardiography provides a rapid, noninvasive test in the diagnosis of acute, severe mitral regurgitation resulting from papillary muscle rupture. This report illustrates the usefulness of echocardiography to determine the cause of acute mitral regurgitation.

Ventral abdominal, transdiaphragmatic approach for implantation of cardiac pacemakers in the dog

Surgical implantation of a sutureless myocardial electrode and pulse generator was performed in 18 dogs, using a ventral abdominal, transdiaphragmatic approach. Twelve dogs were greater than or equal to 10 years old. The 18 dogs weighed from 3 to 54 kg. Indications for permanent cardiac pacemaker implantation included complete (3rd degree) atrioventricular block, sick sinus syndrome, and sinus bradycardia. Few complications developed during or after surgery. One dog died during surgery from ventricular fibrillation, and hypertrophic cardiomyopathy was found at necropsy. Five dogs died 1 to 19 months after surgery (mean, 8.6 months) because of renal failure, hepatic cirrhosis, congestive cardiomyopathy, or idiopathic causes. Twelve dogs were alive 1 to 48 months after surgery (mean, 15.1 months). The surgical approach was used a second time in 3 dogs to replace the myocardial electrode wire and pulse generator 4, 16, and 26 months after surgery; technical complications were not associated with the second surgery in these 3 dogs. In 2 dogs that had initial pacemaker implantation via lateral thoracotomy, a transdiaphragmatic approach was used to replace the myocardial electrode lead and pulse generator 25.5 and 26 months after surgery. According to results of this study, the ventral abdominal, transdiaphragmatic approach for permanent pacemaker implantation in the dog is a simpler technique, with decreased surgery time, decreased time of tissue exposure, and decreased rate of infection, as compared with results described by investigators who used lateral thoracotomy or midline celiotomy and caudal one-third median sternotomy.

Clinical and pathologic findings in dogs with atherosclerosis: 21 cases (1970-1983)

Atherosclerosis was diagnosed on necropsy in 21 dogs in a 14-year period. Nine dogs died and 12 were euthanatized because of complications associated with the disease. The mean age was 8.5 +/- 0.5 years; 18 dogs were male. Three breeds (Miniature Schnauzer, Doberman Pinscher, and Labrador Retriever) had a higher prevalence of the disease than other breeds in the canine necropsy population of The Animal Medical Center. Most common clinical signs were lethargy, anorexia, weakness, dyspnea, collapse, and vomiting. Hypercholesterolemia, lipidemia, and hypothyroidism were common in affected dogs tested, and protein electrophoresis revealed high values for alpha 2 and beta fractions in all dogs tested. Electrocardiography indicated conduction abnormalities and myocardial infarction in 3 of 7 dogs. Necropsy revealed that affected arteries (including coronary, myocardial, renal, carotid, thyroidal, intestinal, pancreatic, splenic, gastric, prostatic, cerebral, and mesenteric) were yellow-white, thick and nodular, and had narrow lumens. Myocardial fibrosis and infarction also were observed in the myocardium. Histologically, affected arterial walls contained foamy cells or vacuoles, cystic spaces, mineralized material, debris with or without eroded intima, and degenerated muscle cells.

Nonsurgical removal of a catheter embolus from the heart of a dog

A fragment of an 18-gauge catheter was inadvertently severed during catheterization of the cephalic vein in a 7-year-old Golden Retriever. Under fluoroscopic guidance, the fragment was retrieved successfully from the right ventricle, using a self-constructed, loop-snare catheter.

Echocardiographic reference values in healthy cats sedated with ketamine hydrochloride

An M-mode echocardiographic examination was performed in a consistent manner in 30 clinically healthy cats under light ketamine hydrochloride sedation. There was a significant linear relationship between increasing body size and increasing cardiac dimensions for several echocardiographic values. Positive correlation existed between body weight and body surface area with aortic root, left ventricular caudal wall thickness (LVCW), interventricular septal thickness (IVS), IVS/LVCW, and mean velocity of circumferential fiber shortening (Vcf); there was a negative correlation between body weight and body surface area with left ventricular ejection time (LVET). Body surface area also correlated positively with percentage of ventricular minor axis dimensional change (% delta D). Positive correlations were recorded between left ventricular end-diastolic dimension (LVEDD) and left ventricular endsystolic dimension (LVESD), LVESD and LVET, LVCW and IVS, LVET (calculated by LVCW motion) and LVET (calculated by aortic valve motion), % delta D and Vcf, heart rate and Vcf, and Vcf (calculated using aortic valve motion to compute LVET) and Vcf (using LVCW motion to compute LVET). There were negative correlations between LVEDD and % delta D, LVEDD and Vcf, LVESD and Vcf, LVET and Vcf, LVET and heart rate, LVET and % delta D. Significant differences were recorded between means of echocardiographic reference values generated in this and other studies, except for LVESD.

Hypertropic cardiomyopathy and hyperthyroidism in the cat

In a 21/2-year period, hypertrophic cardiomyopathy was found at necropsy of 23 cats that died (13 cats) or were euthanatized (10) because of problems associated with hyperthyroidism. Of these, 4 (17%) also had evidence of cardiac failure (pulmonary edema or pleural effusion). The mean body weight of the cats with hyperthyroidism and hypertrophic cardiomyopathy was significantly less (P less than 0.001) than that of clinically normal cats and cats with primary cardiomyopathy (congestive or restrictive) or excessive moderator band cardiomyopathy. In addition, the ratio of heart weight to body weight was significantly greater (P less than 0.001) in the 23 hyperthyroid cats than in the normal cats and cats with primary cardiomyopathy. Twenty (87%) of the cats had symmetric hypertrophy of the ventricular septum and left ventricular free wall, whereas the remaining 3 cats had disproportionate thickening of the ventricular septum, compared with the free wall, similar to what is found in cats with asymmetric hypertrophic cardiomyopathy. Histologic cardiac abnormalities included large, hyperchromatic nuclei, interstitial fibrosis, endocardial fibroplasia, fibrosis of the atrioventricular node, and marked disorganization of cardiac muscle cells. The study showed that hypertrophic cardiomyopathy develops in most hyperthyroid cats, some of which also develop congestive heart failure. Although the signs of heart disease in primary myocardial disease and thyrotoxic disease are similar, the characteristic signalment and clinical signs of hyperthyroidism should lead one to suspect the association of hypertrophic cardiomyopathy with the hyperthyroidism.

Thread and sewing needles as gastrointestinal foreign bodies in the cat: a review of 64 cases

Sixty-four cases of gastrointestinal linear foreign body in the cat were reviewed. Most of the cats were less than 4 years old. The most common clinical signs were persistent vomiting, partial to complete anorexia, and depression. Abdominal palpation by itself was rarely diagnostic. Diagnosis in approximately 75% of the cases was possible, however, by using a combination of oral examination and abdominal palpation. Survey radiography contributed to the diagnosis in 86% of the cases in which it was used, based on evidence of bowel plication, presence of tapered, enteric gas bubbles, gathering of the small intestine, peritonitis, intestinal needles, or bowel obstruction. Surgery (gastrotomy and multiple enterotomies) was necessary in 96.9% of the cases, and most of the cats so treated did well (83.9%). Approximately 50% of the cats with linear foreign body-induced bowel lacerations recovered.

Feline hyperthyroidism: pretreatment clinical and laboratory evaluation of 131 cases

Hyperthyroidism was diagnosed in 131 cats during a 3 1/2-year period. The cats ranged in age from 6 to 20 years; there was no breed or sex predilection. The most frequent clinical signs included weight loss, polyphagia, increased activity, polydipsia, polyuria, and vomiting. Common serum biochemical abnormalities included high values for alkaline phosphatase activity (75%), lactate dehydrogenase activity (66%), aspartate transaminase activity (66%), and alanine transaminase activity (54%). Electrocardiographic changes included tachycardia (greater than or equal to 240 beats/min) and increased R-wave amplitude in lead II (greater than or equal to 0.9 mV) in 66% and 29% of the 131 cats, respectively. Thoracic radiography in 82 cats revealed cardiomegaly in 40 (49%) of these cats; 16 cats with congestive heart failure also had pulmonary edema or pleural effusion. In 5 cats with markedly increased fecal volume, mean 48-hour fecal fat content was significantly greater than normal, with daily fat excretion 2 to 15 times the upper limit of normal. Base-line serum thyroxine concentrations were increased above normal range in all cats, whereas triiodothyronine concentrations were increased in 127 (97%) of the 131 cats. In 11 cats tested, mean thyroxine concentration did not increase significantly after thyroid-stimulating hormone administration. Mean 24-hour percentage of thyroid radioiodine uptake in 32 hyperthyroid cats was significantly higher (39.1%) than normal (9.2%). Thyroid scans, performed on 126 cats, showed enlargement and increased radionuclide accumulation in 1 thyroid lobe in 36 (29%) and both lobes in 90 (71%) of the cats.