Aorto-cardiac fistulas in seven horses.

This research examines the occurrences, symptoms, diagnosis, treatment, and outcomes of aorto-cardiac fistula (a rare heart condition) in seven horses. The horses studied include different genders, breeds, and ages, and the research provides valuable insight into the condition’s manifestation and management.

Objective and Sample Selection

• The research seeks to detail the history, clinical indicators, diagnostic procedures, treatment options, results, and post-mortem findings in horses affected by aorto-cardiac fistula.
• The sample comprises seven horses, including five stallions, one gelding, and one mare. The selected horses belong to different breeds – two Thoroughbreds, two Arabians, two Standardbreds, and one Thoroughbred crossbreed. The age of the horses ranged from 6 to 18 years, with an average age of 12 years.

Symptoms and Diagnosis

• The typical signs that prompted investigation included acute distress (in four horses), intolerance to exercise (in two horses), and one case where the issue was discovered during a routine examination.
• Electrocardiogram results indicated that five horses had monomorphic ventricular tachycardia (a fast heart rhythm originating from the ventricles) on admission, with one additional case that had a previous history of the same.
• Five of the seven horses portrayed a characteristic continuous murmur primarily heard in the right fourth intercostal space.
• Echocardiography (used in six cases) and post-mortem examination (conducted in four cases) substantiated that all seven horses suffered from aorto-cardiac fistulas that arose from the right aortic sinus.

Further Findings and Treatment

• Additional pathological findings included two horses with ruptures in aneurysmal dilations of the aortic wall and dissecting tracts found in the septal myocardium in five cases.
• The fistulas extended into the right ventricle (four cases), right atrium (two cases), and left ventricle (one case).
• The horses survived for periods ranging from 24 hours to four years after the diagnosis.

Conclusion and Recommendations

• The research concludes that aorto-cardiac fistula occurrences should be considered when diagnosing horses, particularly middle-aged or older stallions, exhibiting symptoms such as acute stress, bounding arterial pulse, right-sided continuous murmur, and/or monomorphic ventricular tachycardia.
• The study recommends echocardiography as an effective diagnostic technique for diagnosing the condition and revealing additional heart issues.