J.-L. Pouchelon

Prospective Echocardiographic and Tissue Doppler Imaging Screening of a Population of Maine Coon Cats Tested for the A31P Mutation in the Myosin-Binding Protein C Gene: A Specific Analysis of the Heterozygous Status

BACKGROUNDnA mutation in the sarcomeric gene coding for the myosin-binding protein C gene has been identified in a colony of Maine Coon cats with hypertrophic cardiomyopathy (MyBPC3-A31P mutation). However, the close correlation between genotype and phenotype (left ventricular hypertrophy [LVH] and dysfunction) has never been assessed in a large population, particularly in heterozygous (Hetero) cats.nnnOBJECTIVESnTo investigate LV morphology and function with echocardiography and tissue Doppler imaging (TDI) in a population of Maine Coon cats tested for the MyBPC3-A31P mutation with focus on Hetero animals.nnnANIMALSnNinety-six Maine Coon cats.nnnMETHODSnProspective observational study. Cats were screened for the MyBPC3-A31P mutation and examined with both echocardiography and 2-dimensional color TDI.nnnRESULTSnFifty-two out of 96 cats did not have the mutation (wild-type genotype, Homo WT), 38/96 and 6/96 were Hetero- and homozygous-mutated (Homo M) cats, respectively. Only 11% of Hetero cats (4/38) had LVH and 29% (10/34) of Hetero cats without LVH were >4 years old (4.1-11.5 years). LVH was also detected in 2 Homo WT cats (4%). A significantly decreased (P < .05) longitudinal E/A (ratio between early and late diastolic myocardial velocities) in the basal segment of the interventricular septum was observed in Hetero cats without LVH (n = 34) compared with Homo WT cats without LVH (n = 50), thus confirming that the Hetero status is associated with regional diastolic dysfunction (P < .05).nnnCONCLUSIONSnThe heterozygous status is not consistently associated with LVH and major myocardial dysfunction. Moreover, Homo WT cats can also develop LVH, suggesting that other genetic causes might be implicated.

Comparative Echocardiographic and Clinical Features of Hypertrophic Cardiomyopathy in 5 Breeds of Cats: A Retrospective Analysis of 344 Cases (2001–2011)

BACKGROUNDnPrimary hypertrophic cardiomyopathy (HCM) is the most common feline heart disease and has been demonstrated to be inherited in some breeds. However, few studies have compared HCM phenotypes and survival according to breed.nnnOBJECTIVESnTo compare epidemiological characteristics, clinical findings, left ventricular (LV) geometric patterns, and survival in several breeds of cats with HCM.nnnANIMALSnThree hundred and forty-four cats from 5 different breeds (Persian, Domestic Shorthair [DS], Sphynx, Maine coon [MC], and Chartreux) with primary HCM diagnosed by conventional echocardiography.nnnMETHODSnRetrospective study. Cats were classified according to breed and clinical status.nnnRESULTSnAge at the time of diagnosis was lower (P < .001) in MC (median age, 2.5 years) and Sphynx (3.5 years) than in other breeds (OB), ie, 8.0, 8.0, and 11.0 years for DS, Chartreux, and Persians, respectively. The prevalence of LV outflow tract obstruction was higher (P < .001) in Persians (23/41; 56%) than in OB (115/303; 38%). Age at the first cardiac event was lower (P < .01) in MC (median age, 2.5 years) than in OB (7.0 years). All cats surviving > 15 years of age were DS, Persians, or Chartreux. Sudden death (representing 24% of all cardiac deaths) was observed only in 3 breeds (DS, MC, and Sphynx).nnnCONCLUSION AND CLINICAL IMPORTANCEnAs in humans, feline HCM is characterized by marked phenotypic variability with several breed-dependent features regarding epidemiology, LV geometric patterns, and clinical course (ie, age at diagnosis, 1st cardiac event, and cause of death).

Bradykinin restores left ventricular function, sarcomeric protein phosphorylation, and e/nNOS levels in dogs with Duchenne muscular dystrophy cardiomyopathy.

AIMSnCardiomyopathy is a lethal result of Duchenne muscular dystrophy (DMD), but its characteristics remain elusive. The golden retriever muscular dystrophy (GRMD) dogs produce DMD pathology and mirror DMD patients symptoms, including cardiomyopathy. We previously showed that bradykinin slows the development of pacing-induced heart failure. Therefore, the goals of this research were to characterize dystrophin-deficiency cardiomyopathy and to examine cardiac effects of bradykinin in GRMD dogs.nnnMETHODS AND RESULTSnAt baseline, adult GRMD dogs had reduced fractional shortening (28 ± 2 vs. 38 ± 2% in control dogs, P < 0.001) and left ventricular (LV) subendocardial dysfunction leading to impaired endo-epicardial gradient of radial systolic velocity (1.3 ± 0.1 vs. 3.8 ± 0.2 cm/s in control dogs, P < 0.001) measured by echocardiography. These changes were normalized by bradykinin infusion (1 µg/min, 4 weeks). In isolated permeabilized LV subendocardial cells of GRMD dogs, tension-calcium relationships were shifted downward and force-generating capacity and transmural gradient of myofilament length-dependent activation were impaired compared with control dogs. Concomitantly, phosphorylation of sarcomeric regulatory proteins and levels of endothelial and neuronal nitric oxide synthase (e/nNOS) in LV myocardium were significantly altered in GRMD dogs. All these abnormalities were normalized in bradykinin-treated GRMD dogs.nnnCONCLUSIONSnCardiomyopathy in GRMD dogs is characterized by profound LV subendocardial dysfunction, abnormal sarcomeric protein phosphorylation, and impaired e/nNOS, which can be normalized by bradykinin treatment. These data provide new insights into the pathophysiological mechanisms accounting for DMD cardiomyopathy and open new therapeutic perspectives.

Systolic arterial blood pressure in small-breed dogs with degenerative mitral valve disease: A prospective study of 103 cases (2007–2012)

The objective of this prospective observational study was to assess systolic arterial blood pressure (SABP) in small-breed dogs with degenerative mitral valve disease (MVD) from different International Small Animal Cardiac Health Council (ISACHC) heart failure classes. For this purpose, 103 client-owned dogs weighing <20 kg (mean ± standard deviation, 8.5 ± 3.0 kg; aged 9.8 ± 2.9 years) and presenting with MVD diagnosed by echo-Doppler examination were enrolled. Nineteen healthy dogs (9.9 ± 2.3 years; 8.7 ± 4.2 kg) were concurrently recruited as controls. SABP was measured in unsedated dogs using the Doppler method according to the recommendations in the American College of Veterinary Medicine consensus statement. SABP was significantly increased in dogs in ISACHC class 1 (n=53; median, interquartile range 140 mmHg, 130-150 mmHg) and class 2 (n=21; 140 mmHg, 130-150 mmHg), compared to the control group (n=19; 130 mmHg, 120-140 mmHg; P<0.01 and P<0.05, respectively), but remained within the reference interval (≤ 160 mmHg). Conversely, dogs in ISACHC class 3 showed a significantly lower SABP (n=29, 120 mmHg, 110-130 mmHg) than those from all other ISACHC classes (P<0.001) and the controls (P<0.05). Additionally, SABP<120 mmHg was recorded in 13/103 dogs (13%). The 13 dogs were all ISACHC class 3 (3a or 3b) and were under medical treatment for heart failure. In conclusion, MVD was often associated with SABP values that were within the reference interval, but at its upper end. However, a significant decrease in SABP was observed in dogs with ISACHC heart failure class 3. Whether such low SABP values resulted from an MVD-related decrease in cardiac output, an afterload reduction owing to cardiac treatment, or both, remains to be determined.

Successful Treatment of a Congenital Pulmonic Valvular Stenosis in a Snow Leopard (Uncia uncia) by Percutaneous Balloon Valvuloplasty

Abstract A 3-yr-old intact female snow leopard (Uncia uncia) was evaluated for progressive apathy, lethargy, and decreased appetite. Cardiac auscultation revealed a left basal grade IV/VI systolic ejection murmur, and an echocardiogram confirmed a severe pulmonic valvular stenosis (pressure gradient of 98 mm Hg). The lesion was managed by balloon valvuloplasty, resulting in a marked pressure gradient reduction (30 mm Hg). The cat recovered well, and clinical signs resolved. This is the first description of a pulmonary valve stenosis and management with balloon valvuloplasty in a wild felid.

Short-Term Efficacy and Safety of Torasemide and Furosemide in 366 Dogs with Degenerative Mitral Valve Disease: The TEST Study

Background Furosemide is the only loop diuretic recommended by the ACVIM consensus guidelines for treatment of congestive heart failure (CHF) in dogs related to degenerative mitral valve disease (DMVD). Torasemide is another potent loop diuretic with a longer half‐life and a higher bioavailability. Objectives (1) To demonstrate that torasemide given once a day (q24h) is noninferior to furosemide given twice a day (q12h) for treating dogs with CHF; (2) and to compare the effect of the 2 drugs on the time to reach a composite cardiac endpoint “spontaneous cardiac death, euthanasia due to heart failure or CHF class worsening.” Animals A total of 366 dogs with CHF attributable to DMVD. Methods Analysis of 2 prospective randomized single‐blinded reference‐controlled trials was performed. Dogs orally received either torasemide q24h (n = 180) or furosemide q12h (n = 186) in addition to standard CHF therapy over 3 months. The primary efficacy criterion was the percentage of dogs with treatment success assessed in each study. The time to reach the composite cardiac endpoint was used as secondary criterion in the overall population. Results Torasemide was noninferior to furosemide (P torasemide − P furosemide = +7%; 95% CI [−8%; +22%] and P torasemide − P furosemide = +1%; 95% CI [−12%; +14%], respectively, in Study 1 and Study 2). Torasemide (median dose = 0.24 mg/kg/d q24h; range = 0.10–0.69 mg/kg/d) was associated with a 2‐fold reduction in the risk of reaching the composite cardiac endpoint (adjusted HR = 0.47; 95% CI = 0.27–0.82; P = 0.0077) as compared with furosemide (median dose = 1.39 mg/kg q12h; range = 0.70–6.30 mg/kg q12h). Conclusions and Clinical Importance Torasemide q24h is an effective oral diuretic in dogs with CHF.

Intracardiac echocardiography: use during transcatheter device closure of a patent ductus arteriosus in a dog ☆

Intracardiac echocardiography (ICE) is used in humans for percutaneous interventional procedures, such as transcatheter device closures. Intracardiac echocardiography provides high-resolution imaging of cardiac structures with two-dimensional, M-mode, Doppler, and also three-dimensional modalities. The present report describes application of ICE during transcatheter occlusion of patent ductus arteriosus using a canine ductal occluder in a dog for which transesophageal echocardiography could not provide an optimal acoustic window.

PREVALENCE OF VALVULAR REGURGITATIONS IN CLINICALLY HEALTHY CAPTIVE LEOPARDS AND CHEETAHS: A PROSPECTIVE STUDY FROM THE WILDLIFE CARDIOLOGY (WLC) GROUP (2008–2013)

Abstract:u2003 The purpose of this prospective study was to evaluate transthoracic echocardiograms from clinically healthy large felids for the presence of valvular regurgitations (VR). Physiologic VR commonly occur in normal dogs and cats, but the percentage of large felids with VR has not been previously reported. During a 5-yr study period (2008–2013), 28 healthy animals were evaluated under general anesthesia: 16 cheetahs (Acinonyx jubatus soemmeringuii) with a mean age of 1.5 ± 0.8 yr (range 0.7–3.5 yr), 5 Amur leopards (Panthera pardus orientalis), 1 snow leopard (Uncia uncia), and 6 clouded leopards (Neofelis nebulosa). For this study, all the leopards were gathered in one so-called “leopards group” with a mean age of 2.8 ± 3.4 yr (range 0.3–10.7 yr). All valves observed in each view were examined for evidence of regurgitant jets and turbulent blood flow using the color-flow Doppler mode. Valves were also examined for structural changes. Mitral valve and aortic cusp abnormalities were considered to be of congenital origin. Mitral valve lesions led to mitral insufficiency in all the felids. Aortic cusp abnormalities led to aortic regurgitation in 94% of the cheetahs and 67% of the leopards. Leopards showed a predominance of early systolic mitral regurgitations, whereas all the mitral regurgitation jets in cheetahs were holosystolic. Tricuspid regurgitation was found in 81% of the cheetahs and in 50% of the leopards, whereas pulmonic regurgitation was detected in 44% of the cheetahs and 33% of the leopards. Interestingly, none of these tricuspid and pulmonic regurgitations were associated with two-dimensional structural valve abnormalities, thus suggesting their physiologic origin, as described in humans, cats, and dogs. In conclusion, subclinical valvular diseases are common in apparently healthy leopards and cheetahs. Longitudinal follow-up of affected animals is therefore required to assess their clinical outcome.

Feasibility, Within-Day and Between-Day Variability of Transthoracic Echocardiography in Sloths (Bradypus Variegatus and Choloepus Hoffmanni)

Bradypus variegatus (Xenarthra, Bradypodidae) and Choloepus hoffmanni (Xenarthra, Megalonychidae) are sloths from the tropical rain forest of the Caribbean and Pacific regions of Costa Rica. Because of their unique physiology and behavior, sloths have intrigued scientists, and several studies have already been conducted regarding blood pressure and heart rate variations. However, the use of transthoracic echocardiography (TTE) in these species has never been reported. The aim of the present study was therefore to determine the feasibility, and then the within-day (repeatability) and between-day (reproducibility) variability of TTE in sloths. A total of 36 TTE examinations (including a total of 1080 measurements) with continuous ECG monitoring were performed on 4 different days by a trained observer on 6 healthy, adult, sedated Choloepus hoffmanni (sexually intact females, age, mean ± SD [minmax] 5.1 ± 1.3 years [4.0-7.5]) from the Costa Rica Animal Rescue Centre. Standard transthoracic M-mode and two-dimensional mode measurements included left ventricular (LV) end-diastolic and endsystolic diameters and thicknesses, the LV fractional shortening, the E point-to-septal separation, the left atrium-to-aorta ratio, and the right atrial width-to-the left atrial width ratio. Pulsed-wave Doppler parameters included peak systolic aortic and pulmonary flow velocities as well as early and late diastolic mitral flow velocities. A general linear model was used to determine the within-day and between-day coefficients of variation (CV). The main results were the following: all measurements could be performed at each TTE examination. Most within- and between-day CV values (90%) were <15%, the lowest being observed for the right atrial width-to-left atrial width ratio (2.2%). These results suggest that TTE is feasible and reliable in sloths, and therefore can be part of the cardiovascular exploration in these species. Further studies are now required to determine the corresponding reference intervals.

PROPOSED SIMPLE METHOD FOR ELECTROCARDIOGRAM RECORDING IN FREE-RANGING ASIAN ELEPHANTS (ELEPHAS MAXIMUS)

Abstract Electrocardiography represents a relevant diagnostic tool for detecting cardiac disease in animals. Elephants can present various congenital and acquired cardiovascular diseases. However, few electrophysiologic studies have been reported in captive elephants, mainly due to challenging technical difficulties in obtaining good-quality electrocardiogram (ECG) tracings, and no data are currently available for free-ranging Asian elephants (Elephas maximus). The purpose of this pilot prospective study was to evaluate the feasibility of using a simple method for recording ECG tracings in wild, apparently healthy, unsedated Asian elephants (n = 7) in the standing position. Successful six-lead recordings (I, II, III, aVR, aVL, and aVF) were obtained, with the aVL lead providing the best-quality tracings in most animals. Variables measured in the aVL lead included heart rate, amplitudes and duration of the P waves, QRS complexes, T and U waves, and duration of the PR, QT, and QU intervals. A negative deflection following positive P waves, representative of an atrial repolarization wave (Ta wave), was observed for five out of the seven elephants.