Auscultation in mild mitral regurgitation in dogs: observer variation, effects of physical maneuvers, and agreement with color Doppler echocardiography and phonocardiography

Observer variation in diagnosing mild mitral regurgitation in dogs by cardiac auscultation was assessed by having 6 veterinarians with different levels of experience examine 57 Cavalier King Charles Spaniels. Comparisons with color Doppler echocardiography and phonocardiography were made, and the effects of 2 physical maneuvers on the auscultatory findings were evaluated. Using mildly diseased dogs, interobserver agreement in diagnosing the presence or absence of left-sided murmurs ranged from 63% to 88%. The agreement with phonocardiography (range, 53-91%) increased with the amount of observer experience. The 2 most experienced observers could discern soft ejection murmurs from regurgitant murmurs and were able to diagnose 89% of the dogs with regurgitant jets larger than 30% of the left atrial area. In general, less experienced observers diagnosed most jets larger than 50%. In many dogs with small jets, no murmur was found by auscultation and phonocardiography. The audibility of mild regurgitation was significantly reduced in dogs that were difficult to auscultate. Early systolic murmurs were typical of mild regurgitation, whereas holosystolic murmurs typified severe regurgitation. In a few dogs, late systolic murmurs alternated with holosystolic murmurs. Systolic clicks were found phonocardiographically in 18 dogs with mild to moderate regurgitation, but the audibility apparently was low. In many mildly affected dogs, physical maneuvers increased murmur intensity. Thus, some form of dynamic auscultation might facilitate the diagnosis of mild regurgitation. Auscultatory findings in mild regurgitation appear to depend on observer experience, circulatory status, and how difficult the dog is to auscultate.     

迷你岩桐组织培养及植株再生体系建立

以迷你岩桐(Sinningia hybrida‘Isa’s Murmur’)带柄叶片为外植体,探讨了外植体的灭菌方法、不同基本培养基以及外源激素(6-BA、NAA、IBA)对愈伤组织和不定芽的诱导及增殖、生根等的影响,成功建立了迷你岩桐组织培养植株再生体系。结果表明:迷你岩桐带柄叶片在75%乙醇灭菌10 s,0.1%升汞灭菌300 s时,污染率较低(15.56%)而启动率较高(85.56%)。在MS培养基中添加2.0 mg·L^-16-BA和0.1 mg·L^-1 NAA时,愈伤组织诱导率最高(91.11%)。在1/2 MS培养基中添加2.0 mg·L^-16-BA和0.05 mg·L^-1 NAA时,不定芽诱导率为88.89%。在MS培养基中同时添加2.0 mg·L^-16-BA和0.1 mg·L^-1 NAA时,不定芽增殖效果最好,增殖倍数为2.38。1/2 MS+0.10 mg·L^-1 IBA培养基有利于生根,生根率为87.78%。腐殖土∶泥炭土∶河沙以体积比为1∶2∶2的混合基质为移栽基质时,瓶苗移栽成活率可达96.67%。本研究结果可为迷你岩桐的遗传转化体系的构建及规模化生产提供一定的理论基础和技术支撑。     

Use of Auscultation and Doppler Echocardiography in Boxer Puppies to Predict Development of Subaortic or Pulmonary Stenosis

Background: Boxers are predisposed to subaortic and pulmonic stenosis (SAS, PS). Screening of puppies may be useful in estimating the risk of their developing a defect that potentially compromises life expectancy or exercise tolerance.
Hypothesis: Presence of SAS or PS in adult Boxers can be predicted by auscultation and Doppler echocardiography at 9–10 weeks of age.
Animals: Eighty-five Boxer puppies examined at 9–10 weeks of age and at 12 months of age.
Methods: Prospective, longitudinal observational study. Auscultation by stethoscope and continuous wave-Doppler echocardiography for peak velocities ( V _max) in the aorta (Ao) and pulmonary artery (PA).
Results: Intensity of heart murmurs in puppies correlated with V _maxAo and V _maxPA in adults. V _maxAo and V _maxPA in puppies correlated with V _maxAo and V _maxPA in adults, respectively. From puppy to adult, V _maxAo increased and V _maxPA remained unchanged. The negative predictive value for absent or only a soft (≤II/VI) murmur in puppies being associated with V _maxAo and PA ≤ 2.4 m/s as an adult was 90% and ≤3.5 m/s 100%. The negative predictive value of a V _max≤ 2.4 m/s as a puppy still being ≤2.4 m/s as an adult was 94% for Ao and 96% for PA, and of a V _max≤ 3.5 m/s, 99% for Ao and 100% for PA.
Conclusions and Clinical Importance: Even though V _maxAo increases during growth in Boxer puppies, indicating relative narrowing of the aorta, puppies with V _maxAo ≤ 2.4 m/s do not usually progress to clinically have relevant SAS at 12 months of age.     

Dynamic right ventricular outflow obstruction: a new cause of systolic murmurs in cats

We have identified and characterized a new cause of variable parasternal systolic murmurs in cats. Color Doppler echocardiography of 51 cats presented for evaluation of a cardiac murmur demonstrated a localized, turbulent systolic jet located within the right ventricular (RV) outflow region, originating just cranial to the tricuspid valve. Spectral Doppler tracings of the turbulent jets showed abnormally high peak velocity, late systolic flow acceleration, and marked variability with heart rate, typical of dynamic stenosis. Frame-by-frame examination of 2-dimensional (2D) echocardiographic images after color Doppler subtraction revealed systolic apposition of the RV free wall with the interventricular septum at the origin of the turbulent jets. Therefore, we termed this turbulent flow pattern "dynamic right ventricular obstruction" (DRVO). Most cats with DRVO were >4 years old (45 of 51, 88%) and initially presented with concurrent noncardiac disease (73%). Noncardiac diseases associated with DRVO in older cats included high cardiac output states (hyperthyroidism, anemia, and inflammatory disease) and chronic renal failure with and without systemic hypertension. Of the 45 cats >4 years old, 4 (9%) had no evidence of any other cardiac or noncardiac disease. In contrast, 5 of 6 cats (83%) <4 years old had concurrent cardiac disease. No breed predisposition was identified. Follow-up examination of 10 cats demonstrated no change in the disorder in 8 cats but revealed the disappearance of the murmur and abnormal RV Doppler flow signal in 2 cats after renal transplantation. We propose that DRVO is a physiologic cause of systolic murmurs in cats attributable to RV systolic narrowing.     

Prediction of clinically important acquired cardiac disease without an echocardiogram in large breed dogs using a combination of clinical,radiographic and electrocardiographic variables

IntroductionLarge breed (LB) dogs develop dilated cardiomyopathy (DCM) and myxomatous mitral valve disease (MMVD). Echocardiography is required for a definitive diagnosis but is not always available. Our objective was to assess the clinical utility of thoracic radiographs alone and in combination with physical examination and electrocardiography findings for the prediction of clinically important DCM or MMVD in LB dogs.AnimalsFour hundred fifty-five client-owned dogs ≥20 kg with concurrent thoracic radiographs and echocardiogram.Materials and methodsMedical records were reviewed and stored thoracic radiographs and echocardiographic images were measured to classify dogs as normal heart size (NHS), preclinical DCM, clinical DCM, preclinical MMVD (with cardiomegaly), clinical MMVD, or equivocal. Dogs with preclinical MMVD, without cardiomegaly, were classified as NHS. Vertebral heart size (VHS) and vertebral left atrial size (VLAS) were measured. Receiver operating characteristic curves and prediction models were derived.ResultsPrevalence of MMVD (39.3%) was higher than the prevalence of DCM (24.8%), though most MMVD dogs (67.0%) lacked cardiomegaly and were classified as NHS for analysis. The area under the curve for VHS to discriminate between NHS and clinical DCM/MMVD or preclinical DCM/MMVD was 0.861 and 0.712, respectively, while for VLAS, it was 0.891 and 0.722, respectively. Predictive models incorporating physical examination and electrocardiography findings in addition to VHS/VLAS increased area under the curve to 0.978 (NHS vs. clinical DCM/MMVD) and 0.829 (NHS vs. preclinical DCM/MMVD).ConclusionsThoracic radiographs were useful for predicting clinically important DCM or MMVD in LB dogs, with improved discriminatory ability when physical examination abnormalities and arrhythmias were accounted for.     

Congenital supravalvular aortic stenosis in a kitten

A three-month-old, male intact Norwegian forest cat without any clinical signs was referred to the cardiology service of the author’s teaching hospital for evaluation of a cardiac murmur. The murmur was systolic with an intensity of 4 out of 6 with the point of maximal intensity at the left heart base. Echocardiography revealed a moderate mitral valve regurgitation and a moderate dynamic left ventricular outflow tract obstruction both resulting from systolic anterior motion of the mitral valve (SAM). Moreover, left ventricular concentric hypertrophy was noted. Oral atenolol therapy was initiated. Recheck examination 3.5 months later revealed unchanged murmur characteristics in the still asymptomatic kitten. Echocardiography showed no SAM, but there was a severe fixed aortic stenosis apparent caused by a discrete supravalvular lesion, 4 mm distal to the valve, with an hourglass morphology. Supravalvular aortic stenosis is a rare congenital anomaly in cats, which has not been reported antemortem yet.