Buchanan, James W
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Publication Aortic Embolism in Cats: Prevalence, Surgical Treatment and Electrocardiography(1966-10-29) Buchanan, James W; Baker, Gordan J; Hill, John DAortic embolism (caudal arterial thromboembolism) was diagnosed over a four-year-period in 14 out of 2,000 cats in a hospital clinic population (7/1,000). Including 35 cases reported in the literature, the average age of 50 cats with aortic embolism was 6-8 years (range one to 16 years). Of these, 37 were males and 13 were females. Endocarditis with thrombosis was the most frequently observed cause of aortic embolism, although aortic arteriosclerosis was reported in one cat. The clinical and pathological features of aortic embolism in five cats are described in this report. In electrocardiograms of four of these, arrhythmias or conduction disturbances were recorded. Intact emboli in the aorta and external iliac arteries were removed by abdominal aortic embolectomy in two cats within hours after the onset of posterior paralysis. Death resulted in one case from cardiac complications and in the other by euthanasia at the later date because of probably recurrent aortic embolism. In the other three cases, multiple sections of the aorta with the embolus in situ were examined, but no microscopic changes in the aortic wall were noted. Surgical removal of an aortic embolus is technically and economically feasible and is considered the treatment of choice when treatment is requested within hours after the onset of clinical signs. Although embolectomy can yield a good immediate result; the long range justification for such therapy requires further evaluation, since recurrent embolization may develop.Publication Pathogenesis of Single Right Coronary Artery and Pulmonic Stenosis in English Bulldogs(2001-03-01) Buchanan, James WEnglish Bulldogs are the most common breed to have pulmonic stenosis. Previous studies showed that this congenital heart abnormality in Bulldogs frequently is caused by a circumpulmonary left coronary artery originating from a single right coronary artery. Fetal anasarca also occurs often in Bulldogs and might represent congestive heart failure, but the cause is unknown. To determine if fetal anasarca is associated with a coronary anomaly and pulmonic stenosis, major coronary arteries were studied in 6 bulldog puppies with fetal anasarca. Five of the puppies had normal coronary arteries, and this led to the conclusion that fetal anasarca usually is not associated with major coronary abnormalities or pulmonic stenosis. The 6th puppy had single right coronary artery with circumpulmonary left coronary artery and moderate subvalvular pulmonic stenosis. Serial section histology suggests that the underlying cause of this syndrome is malformation of the left aortic sinus (of Valsalva) and inversion of the proximal segment of the left main coronary artery.Publication Familial Dilated Cardiomyopathy of Young Portuguese Water Dogs(1999) Dambach, Donna M; Lannon, Anne; Sleeper, Meg M; Buchanan, James WA novel dilated cardiomyopathy (DCM) in 12 related Portuguese Water Dogs was identified by retrospective analysis of postmortem and biopsy case records. Male and female puppies born to clinically healthy parents typically died at 13 (± 7.3) weeks of age (range, 2–32 weeks) because of congestive heart failure. Puppies died suddenly without previous signs or with mild depression followed by clinical signs of congestive heart failure 1–5 days before death. There was no sex predilection. The hearts were enlarged and rounded, with marked left ventricular and atrial dilation. No other significant structural cardiac defects were noted. The histologic changes in the myocardium were diffuse and characterized by myofibers of irregular sizes separated by an edematous interstitium. The myofibers had multifocal swollen, cleared segments often involving perinuclear areas that contained granular, phosphotungstic-acid-hematoxylin-positive material consistent with mitochondria. There was loss of the cross-striation pattern, and intercalated discs were difficult to identify. There was no evidence of concurrent myocardial fibrosis; rare chronic inflammatory infiltrates were noted in one dog. Noncardiac skeletal muscles were not affected. The underlying cause is unknown. From the pedigree analysis, an autosomal recessive pattern of inheritance is suspected. Based on the histologic findings, this DCM is most likely due to an underlying molecular (biochemical or structural) defect. The early onset and rapid progression of the disease makes this a clinically distinctive form of canine DCM.Publication Mineralization of Short Term Pericardial Cardiac Patch Grafts(1984-01-27) Buchanan, James W; Frasca, P.; Soriano, R. Z; Dunn, J. M; Marmon, L.; Buchanan, Sarah A.; Melbin, J.; Chang, S. H; Golub, E. E; Shapiro, I. MGlutaraldehyde fixed patch grafts of bovine pericardium were implanted in myocardial windows in young (3-4 months old) sheep. The samples were retrieved after one to three weeks for study with scanning electron microscopy (SEM) and energy dispersive x-ray microanalysis (EDX). A layer of porous material (pseudoneointima, PNI), consisting mostly of a dense mesh of fibers interspersed with blood cells, was noted to form on the blood contacting surface of the graft. Four distinct sets of mineralization were noted in the retrieved grafts: (1) at the blood contacting surface of the PNI; (2) within the PNI at the junction between layers of PNI with differing densities; (#) near the junction of PNI and pericardium (but in the PNI); and (4) within the pericardium. In both the PNI and pericardium the mineral was shown by EDX analysis to contain both calcium and phosphorous indicating the mineral to be a calcium phosphate. Mineralization in the PNI differed from that in the pericardium; in the PNI it was deposited in discrete regions and apparently in association with thrombi while in the pericardium it was distributed diffusely within the collagen matrix, which may influence its formation.Publication Left Atrial Paraganglioma in a Dog: Echocardiography, Surgery, and Scintigraphy(1998-03-01) Buchanan, James W; Boggs, Lynne S; Dewan, Stephan; Regan, Joan; Myers, Nathaniel CPrimary tumors of the left atrium are uncommon in dogs and tumor-specific diagnoses have been made only at necropsy. No reports have been found in which the diagnosis was confirmed antemortem and the tumor removed surgically. This report describes a case of obstructive paraganglioma in the left atrium of a dog and long-term survival after surgical removal of most of the tumor using cardiopulmonary bypass. Subsequently, scintigraphy demonstrated the presence of somatostatin receptors in residual tumor in the left atrium. The latter technique may be of value in establishing a definitive diagnosis in future cases of chemodectoma, extra-adrenal paraganglioma, or adrenal paraganglioma (phechromocytoma).Publication Chronic Valve Disease and Left Atrial Splitting in the Dog [Dissertation](1967) Buchanan, James WAge, sex, and breed evaluations of 392 dogs with chronic valve disease (CVD) from a survey of 4,831 dogs revealed a predominance of CVD in purebred male dogs. Male Cocker Spaniels were most frequently affected. A questionnaire survey concerning aspects of medical history, environment, behavior, and survival was made 3-5 years after initial clinical examinations on 471 dogs. This study revealed no marked differences between dogs with CVD and dogs with no heart disease, except that dogs with CVD more often had signs of congestive heart failure. Endocardial and endomyocardial splitting of the left atrium occurred in 30 dogs with CVD; primarily in males of the Dachshund and Cocker Spaniel breeds. Left atrial perforation in several of the cases caused hemopericardium or acquired atrial septal defects which could be diagnosed by clinical means. The cause of splitting was considered to be left atrial dilatation with left atrial degeneration playing primarily a permissive role. Lipid deposition in the endocardium and ruptured chordae tendineae was found in preliminary frozen section studies. A method of postmortem cardiotomy was developed which permitted recognition of spontaneously ruptured cordae tendineae were frequently found in dogs with severe chronic valve disease with or without left atrial splitting. The Dachshund, Cocker Spaniel, and Beagle breeds in varying order constituted the three most common breeds with CVD, left atrial splitting or the intervertebral disc syndrome. This finding was suggestive of an underlying connective tissue disorder predominant in those breeds which have been classified by others as belonging to a "chondrodystrophoid" group. Radiographic studies of dogs with left atrial enlargement revealed a characteristic bulge in the dorsoventral cardiac silhouette caused by dilatation of the left atrial appendage. This was most apparent in dogs with left atrial splitting. Clinical and pathological studies on 60 "hyperimmune" dogs from which blood was withdrawn by cardiocentesis for immune serum production revealed serious heart disease in nearly all dogs. This was considered the results of weekly cardiocentesis for periods up to three years rather than the results of repeated vaccinations during this time.Publication Changing Breed Predispositions in Canine Heart Disease(1993-12-01) Buchanan, James WBreed predispositions for some types of congenital heart disease were recognized 30 years ago and led to breeding experiments that confirmed the genetic transmission of specific congenital heart defects in most instances. As a result, certain breeds were associated with certain diseases, and this became a legitimate consideration in the differential diagnosis of some abnormalities in the absence of more definite diagnostic studies. As an example, a significant systolic murmur in a young Newfoundland dog means sub-aortic stenosis (SAS) until proven otherwise. The diagnosis of SAS is usually confirmed by Doppler echocardiography or angiocardiography. Although cardiologists take breed into consideration, they still rely on proper examination and appropriate diagnostic procedures; however, practitioners are comes pressed to give opinions on the likelihood of particular diagnoses and prognoses without benefit of a full work-up. In this setting, knowledge of new and changing breed predispositions can be helpful. In recent years, some defects and new breeds have been found to be overrepresented in cardiology clinics across the country. All practitioners need to be alert in order to recognize new breed predispositions and counsel breeders accordingly. Of particular note is the rising frequency of SAS in Golden Retriever and Rottweiler dogs. The purpose of this presentation is to describe changing breed predispositions that have been observed in recent years and share the results of a recent tabulation of data at our institution as well as 1987- 1989 data in the national Veterinary Medical Data Base (VMDB) at Purdue University.Publication Persistent Left Cranial Vena Cava in Dogs: Angiocardiography, Significance, and Coexisting Anomalies(1963) Buchanan, James WPersistent left cranial venae were observed in angiocardiograms of 3 dogs at the University of Pennsylvania Veterinary Hospital. Although this vessel seldom has clinical significance, it is hoped this report will spare others the confusion caused by the first case in this series. These 3 dogs and 5 out of 7 others had significant cardiovascular anomalies in addition to persistent left cranial venae cavae.Publication Experimental Studies on Ectopic Atrial Rhythms in Dogs(1967-05-01) Moore, E. Neil; Jomain, Serge L; Stuckey, Jackson H; Buchanan, James W; Hoffman, Brian FPublication First Pacemaker in a Dog: A Historical Note(2003-09-01) Buchanan, James WThe 1st Pacemaker used clinically in a 10-year-old male Basenji dog was implanted in 1967 because the dog had recurrent congestive heart failure because of complete heart block. A fixed-rate (now called VOO) 70-beats per minute (bpm), bipolar pacemaker was placed in the left paralumbar fossa and 2 leads were passed subcutaneously and attached to the left ventricular epicardium through a separate thoracotomy.