Feasibility and clinical utility of transvenous intracardiac echocardiography in conscious, sedated horses.

INTRODUCTION/OBJECTIVES: Intracardiac echocardiography (ICE) is a method of obtaining echocardiographic images with a steerable ultrasound catheter placed within the heart via a venous or arterial approach. The objectives of this study were to assess the feasibility of a 5-10 MHz, 8 French, 90 cm ICE catheter to evaluate cardiac structures and function in standing, sedated horses, and describe standard views in this species. ANIMALS: Ten apparently healthy horses weighing 458.1-618.2 kg from a university teaching herd. MATERIALS AND METHODS: Each horse had a physical examination, transthoracic echocardiography, and ICE performed through a 10 French introducer percutaneously placed in the right jugular vein in the proximal third of the neck with continuous ECG monitoring using telemetry. RESULTS: Three intracardiac echocardiography positions (cranial right atrium, mid right atrium, and right ventricle) with seven views were described with the associated 2D, pulse wave Doppler, continuous wave Doppler, color Doppler, and M-mode image acquisition standardized by referencing the intracardiac positions and common landmarks. The positions were confirmed with simultaneous transthoracic echocardiography. The procedure was well tolerated with only mild, occasional ventricular, and supraventricular arrhythmias that resolved with intracardiac echocardiography catheter repositioning. CONCLUSIONS: Intracardiac echocardiography is feasible, safe, and allows for the acquisition of diagnostic images in conscious, sedated horses.

Clinical Characteristics of Adult Dogs More Than 5 Years of Age at Presentation for Patent Ductus Arteriosus.

BACKGROUND: The median age at presentation for dogs with patent ductus arteriosus (PDA) is <6 months of age, and closure is associated with a decrease in heart size and increased survival time, which are not well described in older dogs. OBJECTIVES: To describe the clinical characteristics of dogs with PDA ≥5 years of age at the time of presentation to a veterinary referral hospital. ANIMALS: 35 client-owned dogs. METHODS: Retrospective case series. RESULTS: PDA was diagnosed at a median age of 7.4 years (range, 5.1-12.3 years). Females represented 23/35 (65.7%) of the patients. Concurrent heart disease included degenerative mitral valve disease (DMVD; 13), arrhythmias (11), pulmonary hypertension (7), and other congenital defects (2). Cardiomegaly was documented in the majority of dogs consisting of left ventricular enlargement (91%) and left atrial enlargement (86%). Median vertebral heart size in 24 dogs was 12.9 (range, 10.7-18.2). The PDA shunt direction was left-to-right in 33 and bidirectional in 2 dogs. Closure was performed in 26 dogs, including 4 with pulmonary hypertension. In 10 dogs receiving furosemide pre-operatively for management of heart failure, furosemide was discontinued (8) or the dosage decreased (2) at the time of discharge. CONCLUSIONS AND CLINICAL IMPORTANCE: Adult dogs can present with a left-to-right shunting PDA that results in cardiomegaly and clinical signs that can improve or resolve with PDA closure. This improvement is also apparent in dogs with PDA complicated by DMVD. Pulmonary hypertension that does not result in complete right-to-left shunting should not be considered a contraindication to closure.