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W e present the case of a patient whose anterior ST elevation in the presence of acute myocardial infarction was caused by the occlusion of a nondominant right coronary artery (RCA). Infrequently, precordial ST elevation can be caused by acute occlusion of the RCA or of one of its branches-a manifestation of isolated right ventricular (RV) infarction 1 that in this instance was not initially recognized during our search for the infarct-related artery. We discuss the patient's case and the rare cause of his cardiac presentation. Case ReportIn October 2009, a 42-year-old man emergently presented with a 2-hour history of chest pain and diaphoresis. His medical history revealed nothing relevant. Immediately upon the patient's arrival, he developed sustained, pulseless, monomorphic ventricular tachycardia. Cardiopulmonary resuscitation was initiated, and he underwent electrical cardioversion to sinus tachycardia. The post-resuscitation electrocardiogram (ECG) showed precordial ST elevation. The patient was immediately taken to the cardiac catheterization laboratory, and an intra-aortic balloon pump was placed.A coronary angiogram showed left dominance (Fig. 1). The left anterior descending coronary artery (LAD) was mildly diseased, had Thrombolysis In Myocardial Infarction-3 flow, and wrapped around the apex. The upper branch of a bifurcating first obtuse marginal branch was occluded (Fig. 1). This occlusion appeared to be chronic, given the presence of a tapered stump. 2 The dominant left circumflex coronary artery was otherwise free of disease. The RCA had a proximal occlusion (Fig. 2). The initial revascularization strategy-attempted recanalization of the occluded obtuse marginal branch-was unsuccessful. Ventricular fibrillation (VF) recurred despite the administration of amiodarone and lidocaine. At this point, it was recognized that the nondominant RCA might be the culprit infarct-related artery, and percutaneous coronary intervention (PCI) was begun.Thrombectomy was performed with use of a 6F right coronary bypass guiding catheter, a 182-cm ChoICE intermediate guidewire (Boston Scientific Corporation; Natick, Mass), and an Export ® XT Aspiration Catheter (Medtronic, Inc.; Minneapolis, Minn). Angioplasty of the proximal vessel, with use of a 3 × 15-mm Quantum Maverick ® balloon catheter (Boston Scientific), restored coronary blood flow. A 2.75 × 32-mm Taxus ® Liberté bare-metal stent (Boston Scientific) was deployed. Be-

Nonatherosclerotic vascular diseases of the mesenteric and renal arteries are considered to occur less frequently than those caused by occlusive atherosclerotic disease. However, when present, they pose a significant diagnostic and therapeutic challenge. Such disorders include fibromuscular dysplasia, median arcuate ligament syndrome, the renal nutcracker syndrome, and some forms of acute and chronic mesenteric ischemia (embolic and thrombotic). This is a heterogeneous group of disorders with substantial differences in the pathogenesis and diagnostic approaches to these diseases. We provide an overview of the pathogenesis, clinical presentation, diagnosis, and current management of fibromuscular dysplasia, median arcuate ligament syndrome, and the renal nutcracker syndrome.