Echo-Doppler and Color-Flow Imaging in Congenital Heart Disease

Aorto-left atrial fistula secondary to aortic infective endocarditis in a dog with a bicuspid aortic valve

An 11-year-old male neutered American bulldog was presented for evaluation of thrombocytopenia, acute onset of ataxia, and vomiting. A new murmur was auscultated on physical examination. Transthoracic echocardiographic examination revealed a bicuspid aortic valve, vegetative lesions on the aortic valve, and continuous shunting from the aortic root to the left atrium through an aorta to left atrial fistula. The dog was euthanized due to its guarded prognosis and critical condition. Pathological examination confirmed presence of a bicuspid aortic valve, aorto-left atrial fistula, and aortic infective endocarditis. Antemortem blood culture revealed two unusual organisms: Achromobacter xylosoxidans and Fusobacterium mortiferum.

Unusual Presentation of Aortic Valve Infective Endocarditis in a Dog: Aorto-Cavitary Fistula, Tricuspid Valve Endocarditis, and Third-Degree Atrioventricular Block

Simple Summary

In dogs, infective endocarditis represents a rare but clinically relevant disease that typically involves the aortic and/or mitral valve. Transthoracic echocardiography plays an essential role in the diagnosis, prognosis, and monitoring of such a condition. Typical echocardiographic signs of disease progression include left-sided cardiac dilatation and extension of aortic and/or mitral vegetative lesions. Nevertheless, unexpected complications can sometimes develop, especially in the case of the erosion of the periannular tissue caused by lytic enzymes produced by bacteria. This case report describes the coexistence of multiple, uncommon complications of aortic valve infective endocarditis in a dog, namely, aorto-cavitary fistula, tricuspid valve endocarditis and third-degree atrioventricular block. In this study, the combination of the ante mortem (clinical and echocardiographic) and post mortem (gross pathology and histopathology) findings allowed us to gain detailed information on the disease process, its atypical complications, and the associated emodynamic consequences.

Abstract

A 2-year-old Boxer with a history of subaortic stenosis and immunosuppressant therapy developed aortic valve infective endocarditis. On echocardiographic examination with simultaneous electrocardiographic tracing, multiple uncommon periannular complications of the aortic valve endocarditis were found, including aorto-cavitary fistula with diastolic left-to-right shunt, tricuspid valve endocarditis, and third-degree atrioventricular block. Necropsy confirmed the above echocardiographic findings. Although aortic valve endocarditis represents a well-known disease entity in dogs, the dynamic nature of this condition may allow development of complex and uncommon echocardiographic features.

Transvenous Pacing Leads and Systemic Thromboemboli in Patients With Intracardiac Shunts

BACKGROUND

The risk of systemic thromboemboli associated with transvenous leads in the presence of an intracardiac shunt is currently unknown.

METHODS AND RESULTS

To define this risk, we conducted a multicenter, retrospective cohort study of 202 patients with intracardiac shunts: Sixty-four had transvenous leads (group 1), 56 had epicardial leads (group 2), and 82 had right-to-left shunts but no pacemaker or implantable cardioverter defibrillator leads (group 3). Patient-years were accrued until the occurrence of systemic thromboemboli or study termination. Censoring occurred in the event of complete shunt closure, death, or loss to follow-up. Mean ages for groups 1, 2, and 3 were 33.9+/-18.0, 22.2+/-12.6, and 22.9+/-15.0 years, respectively. Respective oxygen saturations were 91.2+/-9.1%, 88.1+/-8.1%, and 79.7+/-6.7%. During respective median follow-ups of 7.3, 9.3, and 17.0 years, 24 patients had at least 1 systemic thromboembolus: 10 (15.6%), 5 (8.9%), and 9 (11.0%) in groups 1, 2, and 3, respectively. Univariate risk factors were older age (hazard ratio [HR], 1.05; P=0.0001), ongoing phlebotomy (HR, 3.1; P=0.0415), and an transvenous lead (HR, 2.4; P=0.0421). In multivariate, stepwise regression analyses, transvenous leads remained an independent predictor of systemic thromboemboli (HR, 2.6; P=0.0265). In patients with transvenous leads, independent risk factors were older age (HR, 1.05; P=0.0080), atrial fibrillation or flutter (HR, 6.7; P=0.0214), and ongoing phlebotomy (HR, 14.4; P=0.0349). Having had aspirin or warfarin prescribed was not protective. Epicardial leads were, however, associated with higher atrial (P=0.0407) and ventricular (P=0.0270) thresholds and shorter generator longevity (HR, 1.9; P=0.0176).

CONCLUSIONS

Transvenous leads incur a >2-fold increased risk of systemic thromboemboli in patients with intracardiac shunts.

Patent ductus arteriosus in elderly patients: clinical and echocardiographic features-a case-based review

Congenital heart disease in adults is a rapidly growing field, with many operated and unoperated infants and children surviving into adulthood. Patent ductus arteriosus is an example of a congenital cardiac defect, which may enable patients to survive well into adulthood without prior recognition or correction before symptoms arise. This case illustrates the clinical and echocardiographic manifestations of patent ductus arteriosus with special emphasis on its 2-dimensional and Doppler findings. Management options for this condition are also briefly addressed.

Infective endocarditis in congenital heart disease

The average life expectancy of patients with congenital heart disease has dramatically improved over the past four decades because of advances in medical and surgical therapy, with patients with complex lesions surviving to adolescence and adulthood. Tetralogy of Fallot, transposition of the great arteries, ventricular septal defects, patent ductus, and bicuspid aortic valves in particular are susceptible to infective endocarditis. Most operated patients are left with some form of residua or sequelae, many of which predispose to infective endocarditis. Surgical palliation, such as systemic-to-pulmonary shunts, and reparative surgery, often requiring prosthetic valve or conduit replacement, are major predisposing conditions. Accordingly, recognition, prevention, and treatment strategies for infective endocarditis assume increasing importance in adolescents and adults with congenital heart disease, operated or not.

Echocardiographic assessment of adults with tetralogy of Fallot

Advances in medical and surgical management of congenital heart disease in the last three decades have resulted in a great many survivors to adulthood. Proper care requires intimate knowledge of the basic malformations and their surgical anatomy and results. Tetralogy of Fallot, the most common cyanotic malformation in adults, represents a spectrum from mild right ventricular outflow tract obstruction to complete pulmonary atresia. Evaluation of surgical residua and sequelae includes imaging of aortic-to-pulmonary arterial palliative shunts, detection of residual ventricular septal defect patch leaks or right ventricular outflow tract obstruction, definition of extracardiac conduit patency, and quantitation of ventricular function and valvular regurgitation. Refined echocardiographic imaging and hemodynamic definition is a mainstay in precise segmental anatomical and hemodynamic assessment. Transesophageal echocardiography is particularly important for intraoperative evaluation of surgical results.