OBJECTIVES

Congenital cardiac defects (CCD) are the most common heart diseases in dogs of less than 1 year of age. The exact prevalence of CCD is uncertain as there are both national and regional differences for certain cardiovascular malformations. Because multiple congenital anomalies may be present in the same dog the chosen method of reporting defects will alter frequency data. The three most common CCD reported in dogs in USA and UK have been patent ductus arteriosus (PDA), (sub)aortic stenosis and pulmonic stenosis (PS). However, most recent reports indicate that subaortic stenosis (SAS) is the most common CCD in dogs in many regions of the world. The aim of this report is to characterize the prevalence of different types of CCD in a population of dogs in the south east of Spain.

MATERIALS

This retrospective study was performed in 80 dogs presented between 1994 and 2001 to Veterinary Teaching Hospital of University of Murcia (Spain) and diagnosed with CCD. A complete information about the history, signalment and physical examination was obtained in each dog. Electrocardiograms and thoracic radiographs were also obtained in most of the dogs examined. The final diagnosis in most of dogs was based on two-dimensional echocardiography in combination with colour flow and spectral Doppler echocardiography. Non-selective angiocardiography was performed in two dogs with persistent left cranial vena cava (PLCVC). Post mortem examination was performed in a total of 15 dogs. The echocardiographic examinations were performed using a 3.5, 5 or a 7.5 MHz transducer with dogs positioned in right and left lateral recumbency. The echocardiograms and Doppler studies were analysed according to the recommendations of the literature.

RESULTS

In 80 dogs, 100 cardiac malformations were found, including subaortic stenosis (28%), pulmonic stenosis (23%), patent ductus arteriosus (17%), ventricular septal defects (13%), persistent left cranial vena cava (6%), mitral valve dysplasia (5%), tricuspid valve dysplasia (3%), Tetralogy of Fallot (1%) atrial septal defect (1%), common atrium (1%), intrapericardial cyst (1%) and persistent right aortic arch (1%). Nineteen dogs had more than one defect occurring simultaneously. Subaortic stenosis, pulmonic stenosis and ventricular septal defects were the most common heart defects seen coexisting with others cardiac malformations. The age at diagnosis ranged from three weeks to 11 years. Twenty-eight different breeds were represented. The most common were Boxer (12 cases), Beagle (eight cases), Poodle (five cases), and German shepherd dog (four cases), Rottweiler (four cases), St Bernard (four cases), and miniature Schnauzer (four cases). Eleven dogs were crossbreed. Forty-four were males and thirty-six were females.

CONCLUSION

The most common congenital cardiac defect was subaortic stenosis followed by pulmonic stenosis, patent ductus arteriosus, ventricular septal defects, atrioventricular valve dysplasia and persistent left cranial vena cava. Coexisting multiple cardiac malformations in the same dog were higher than previously reported. No overall sex predilection was present in this study. This is in agreement with most reports.