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Background: In dogs, treatment of pulmonic valve stenosis (PS) with pulmonary balloon valvuloplasty (PBV) is a viable method to decrease the pressure gradient across the valve. However, to the authors' knowledge, the variables that influence the selection of the correct balloon size for the procedure have not been explored. Moreover, the lesions caused by the procedure have not been detailed., Hypothesis: Variables that influence the measurement of the annulus could affect selection of the balloon size. We sought to determine the effects of treatment when the balloon-to-annulus ratio (BAR) was or > 1.3, but within the recommended range of 1.2-1.5, regardless of whether dilation was performed with single or double balloon technique., Animals: Twenty-five Beagles with PS were studied., Methods: Inter- and intra-observer variability, echocardiography versus angiocardiography, and systolic versus diastolic timing were evaluated for the BAR. Assessment of right ventricular (RV) pressure, Doppler gradient, stenotic valve area, and RV wall thickness were compared before and 1, 90, and 180 days after treatment. Postmortem examination of the heart was done., Results: Significant correlations existed in measurement of the annulus; however, variation existed that would change balloon size. Improvement in the degree of PS was significant regardless of the BAR or single or double ballooning. In the most severely affected dogs, continued improvement was noted on day 90. Postmortem examination revealed tears in the commissures and the valve leaflets., Conclusions: Multiple factors influenced determination of the BAR and a range of 1.2-1.5 was effective without detrimental consequences. Dogs with severe PS had continued decrease in RV pressure 3 months after treatment.

Pulmonic valvuloplasty is a well-established method for the treatment of valvular pulmonic stenosis in people and dogs. In dogs, pulmonic valvuloplasty has been restricted to a single balloon; however, the simultaneous use of two balloons is common in pediatric cardiology. The use of two balloons provides an alternative to the use of a single large balloon in small dogs with a pulmonic anulus size that requires a large dilation catheter and large diameter introducer. Moreover, double balloon valvuloplasty permits dilation in large dogs with large pulmonic anulus sizes for which standard dilation catheters are not available. This report outlines the materials required, describes the technique, gives the advantages and disadvantages encountered when performing percutaneous double balloon valvuloplasty and provides some 'tips' for a successful outcome.

Atrioventricular (AV) canal defects comprise a rare category of congenital heart disease associated with abnormal development of the endocardial cushions. These anomalies include a broad spectrum of lesions involving the atrial septum primum, the inlet portion of the ventricular septum, and the atrioventricular valves. In severe cases heart failure may result. The present report describes cardiopulmonary findings in a six-week-old, female Thoroughbred foal with persistent tachypnea and tachycardia since birth. Clinical, echocardiographic, cardiac catheterization, and pathologic findings were compatible with complete AV canal defect with bi-directional shunting, congestive heart failure, and pulmonary hypertension. Gross cardiac pathologic findings included a large atrioventricular septal defect, a common atriovalvular orifice, five atrioventricular leaflets, with two free-floating bridging leaflets. Histopathologic lesions in the lung included hypertrophy of the pulmonary arteriolar walls due to thickening of the tunica media. This represents a well documented case of complete endocardial cushion defect with anomalous development of the atrioventricular valves and resultant pulmonary hypertension and heart failure.

Transesophageal echocardiography (TEE) enhances our ability to see the patent ductus arteriosus in the dog. The improved visualization may potentially improve our ability to perform transcatheter coil embolization in patients that are more likely to have a successful outcome. This report uses still and video images to detail the specifics of coil embolization as performed with the assistance of TEE and compares the images with those of angiography, surgery and postmortem examination.

Objectives: This report describes a unique group of German shepherd dogs with inherited ventricular arrhythmias and sudden death. Before death, these dogs have no evidence of cardiovascular failure., Background: There are few spontaneous animal models of sudden death that permit intensive investigation., Methods: To determine the temporal evolution of ventricular arrhythmias and to characterize the syndrome of sudden cardiac death in these dogs, 24-h ambulatory electrocardiographic (ECG) monitoring, echocardiograms, electrophysiologic testing and breeding studies were conducted., Results: The 24-h ambulatory ECGs from dogs that died showed frequent ventricular arrhythmias with rapid polymorphic ventricular tachycardia (rates > 480 beats/min). Affected dogs had a window of vulnerability for arrhythmias, with the highest incidence and severity of arrhythmias between 20 to 30 and 40 to 50 weeks of age. Affected dogs that died did not have prolongation of the QT interval over a spectrum of heart rates compared with unaffected dogs. The clinical arrhythmia was not induced in dogs during programmed electrical stimulation. Severely affected dogs monitored > 5 years did not develop any evidence of heart failure or cardiomyopathy, and no histopathologic abnormalities existed. Seventeen dogs died suddenly (age 4 to 30 months) and were either 1) found dead at first observation in the morning (n = 8), 2) observed to die during sleep (n = 4), 3) observed to die while resting after exercise (n = 3), or 4) observed to die during exercise (n = 2). All sudden deaths occurred between the end of September and April, with most (n = 11) during January and February., Conclusions: The cause of the inherited severe ventricular arrhythmias and sudden death in these young German shepherd dogs is still undetermined. A purely arrhythmic disorder is supported by the lack of cardiac pathology. Moreover, the window of vulnerability to ventricular arrhythmias and the age and circumstances of death invite speculation about the role of the autonomic nervous system.