The history of veterinary cardiology.

Throughout civilization, animals have played a pivotal role in the advancement of science and medicine. From as early as 400 BC when Hippocrates recognized that diseases had natural causes, the steadfast advances made by biologists, scientists, physicians and scholars were fueled by timely and important facts and information- much of it gained through animal observations that contributed importantly to understanding anatomy, physiology, and pathology. There have been many breakthroughs and historic developments. For example, William Harvey in the 16th and 17th centuries clarified the importance of the circulatory system, aided by observations in dogs and pigs, which helped to clarify and confirm his concepts. The nineteenth century witnessed advances in physical examination techniques including auscultation and percussion. These helped create the basis for enhanced proficiency in clinical cardiology. An explosion of technologic advances that followed in the 20th century have made possible sophisticated, accurate, and non-invasive diagnostics. This permitted rapid patient assessment, effective monitoring, the development of new cardiotonic drugs, clinical trials to assess efficacy, and multi-therapy strategies. The latter 20th century has marshaled a dizzying array of advances in medical genetics and molecular science, expanding the frontiers of etiologies and disease mechanisms in man, with important implications for animal health. Veterinary medicine has evolved during the last half century, from a trade designed to serve agrarian cultures, to a diverse profession supporting an array of career opportunities ranging from private, specialty practice, to highly organized, specialized medicine and subspecialty academic training programs in cardiology and allied disciplines.

Historical review, epidemiology and natural history of degenerative mitral valve disease.

Chronic mitral valve disease due to myxomatous degeneration (MMVD) is the most common cardiovascular disease in dogs and has been known to cause congestive heart failure for more than 100 years. This article presents an historical perspective of the disease and reviews the most updated data on epidemiology and natural history of MMVD in dogs.

Acquired atrial septal defects secondary to rupture of the atrial septum in dogs with degenerative mitral valve disease.

Acquired atrial septal defects (ASDs) secondary to atrial septal rupture are uncommon in dogs with degenerative mitral valve disease. Echocardiographic diagnosis of these defects has not previously been described. The echocardiographic features in two cases identified antemortem are presented in this report. ASDs can be difficult to identify on two-dimensional echocardiogram when relatively small in size and may be underreported. Acquired ASDs may alter the physiology, treatment plan and prognostic implications for the dogs in which they occur and their presence should be considered in all cases of degenerative mitral valve disease that develop signs of right-sided heart failure.

Tracheal signs and associated vascular anomalies in dogs with persistent right aortic arch.

Medical records of 55 dogs with 1 or more vascular rings around the esophagus and trachea were reviewed to determine the nature and frequency of related vascular anomalies and to determine the reliability of tracheal deviation on radiographs for the diagnosis of persistent right aortic arch (PRAA). Fifty-two (95%) of the 55 dogs had PRAA. Of the 52 dogs with PRAA, 44% had coexisting compressive arterial anomalies: 17 had retroesophageal left subclavian artery and 6 had double aortic arch with atretic left arch. Characteristic tracheal deviation was consistently present in dogs with PRAA. Moderate or marked focal leftward curvature of the trachea near the cranial border of the heart in dorsoventral (DV) or ventrodorsal (VD) radiographs was found in 100% of available radiographs of 27 dogs with PRAA. Moderate or marked focal narrowing of the trachea also was noted in 74% of DV or VD radiographs and 29% of lateral radiographs of the dogs. Tracheal position in 30 of 30 dogs with megaesophagus and 62 of 63 control dogs was midline or rightward in VD or DV radiographs. Histology in a neonatal dog with PRAA revealed evidence of tracheal deviation and compression even before birth. Focal leftward deviation of the trachea near the cranial border of the heart in DV or VD radiographs is a reliable sign of PRAA in young dogs that regurgitate after eating solid food, and contrast esophagrams are not necessary to confirm the diagnosis of vascular ring compression.

Etiology of patent ductus arteriosus in dogs.

Patent ductus arteriosus (PDA) is the most common congenital heart disease in dogs and usually causes heart failure and death unless corrected at a young age. Previous histologic studies in a line of dogs derived from Miniature Poodles with hereditary PDA identified varying degrees of hypoplasia and asymmetry of ductus-specific smooth muscle and the presence of aortalike elastic tissue in the ductus wall sufficient to cause patency. To determine if similar structural abnormalities cause PDA in other dogs, serial-section, 3-dimensional histology of ductal architecture was studied in 8 non-Poodle purebred dogs with PDA with no immediate family history of PDA. Morphologic abnormalities were observed in 7 of 8 dogs with PDA and essentially were the same as those in dogs known to have a hereditary form of PDA. These findings suggest that apparently sporadic PDA in these breeds is caused by a genetic defect in the structure of the ductus arteriosus that is similar or identical to that in the Poodle. The relatives of dogs with PDA, particularly parents, offspring, and siblings, should be screened for evidence of PDA. Dogs with PDA should not be used for breeding, regardless of breed.

The 1st balloon valvuloplasty: an historical note.

Balloon valvuloplasty (BV) is currently the treatment of choice for pulmonic stenosis in humans and dogs. Before permission was obtained to attempt the 1st BV in a child in 1982, the safety and efficacy of the procedure were tested in 1980 in an English Bulldog with spontaneous pulmonic stenosis. A fatal outcome would have caused indefinite postponement of BV in human patients, a procedure that currently benefits over 25,000 patients a year worldwide. This article describes the initial test procedure and its fortunate outcome in spite of unrecognized coronary anomalies in the bulldog. A small balloon was used in the test procedure, and fatal disruption of the anomalous left coronary artery (CA) did not occur as it has in several bulldogs since that time.