Eustachian and Tricuspid Valve Endocarditis: A Rare Consequence of the Automatic Implantable Cardioverter-Defibrillator Placement

Eustachian valve (EV) is usually a rudimentary structure in adults. It is an embryological remnant of sinus venosus that directs oxygenated blood from the inferior vena cava across the foramen ovale and into the left atrium. Intravenous drug use is most commonly associated with infective endocarditis of the right-sided heart structures. Other documented causes of such an occurrence are intracardiac devices like pacemakers and central venous catheters. Patients presenting with concerns of infection and embolic phenomenon should promptly undergo evaluation for infective endocarditis. Although an embryological remnant, the eustachian valve normally regresses after birth, except in a minority of the patients, it persists as a vestigial structure. Here we present an unusual case involving infective endocarditis of the eustachian valve and tricuspid valve both in a patient with recent automatic implantable cardioverter-defibrillator (AICD) placement and history of IV drug abuse and its systemic consequences in a patient with patent foramen ovale.