Cyclic Tachycardia and Hypotension
A 60-year-old man presented to the emergency department with multiple episodes of palpitations, dyspnea, diaphoresis, and lightheadedness. One episode was associated with a syncopal event 1 week before admission. His symptoms recurred during hospitalization, at which time telemetry documented a narrow complex tachycardia at 160 bpm accompanied by hypotension. During the next 24 hours, he developed sinus tachycardia and hypotension followed by normal sinus rhythm and hypertension, which alternated in a cyclic pattern with a periodicity of ≈8 minutes (Figure 1). The patient also developed symptoms of vomiting, constipation, and abdominal distension. An abdominal radiograph showed a severe ileus. Administration of phentolamine and labetalol terminated the pattern of tachycardia and blood pressure instability within hours, and the ileus resolved over the course of 3 to 4 days. Diagnostic evaluation revealed marked elevations in 24-hour urinary metanephrines and vanillylmandelic acid. Supine plasma catecholamine levels were 57 785 pg/mL (normal: 123 to 671 pg/mL), which fractionated as norepinephrine 30 253 pg/mL (normal: 112 to 658 pg/mL) and epinephrine 27 428 pg/mL (normal: <50 pg/mL). A large left adrenal mass was found by CT scan (Figure 2), which enhanced on iodine 131meta-iodobenzylguanidine (MIBG) scan without evidence of metastatic disease (Figure 3). After 2 weeks of medical stabilization, a laparoscopic left adrenalectomy was performed, and histological examination confirmed the diagnosis of pheochromocytoma (Figure 4). Adrenergic blockade was discontinued postoperatively. The patient’s vital signs remained normal and he was discharged in good condition.
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
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