Bidirectional ventricular tachycardia unmasked by beta-blockade in pheochromocytoma presenting as hypertensive optic neuropathy: a case report and literature review

BackgroundPheochromocytoma is a catecholamine-secreting neuroendocrine tumor that can produce life-threatening cardiovascular complications. Bidirectional ventricular tachycardia (BVT) is a rare arrhythmia with a narrow differential diagnosis, classically associated with digitalis toxicity and catecholaminergic polymorphic ventricular tachycardia, and only exceptionally reported as the presenting feature of pheochromocytoma.Case presentationA 51-year-old woman presented with acute visual impairment secondary to hypertensive optic neuropathy; her blood pressure was 220/138 mmHg. Within 24 h of initiating sodium nitroprusside and metoprolol, she developed bidirectional ventricular tachycardia followed by torsades de pointes. Marked blood-pressure lability, dramatically elevated plasma free metanephrines and catecholamines, and a left adrenal mass on computed tomography established the diagnosis of pheochromocytoma. After alpha-adrenergic blockade with phenoxybenzamine, laparoscopic adrenalectomy was performed, and histopathology confirmed the diagnosis. No ventricular arrhythmia recurred, and blood pressure normalized without antihypertensive medication.ConclusionBidirectional ventricular tachycardia may be the initial manifestation of pheochromocytoma and may be unmasked by beta-blockade administered before alpha-blockade. Unexplained BVT accompanied by blood-pressure fluctuations should prompt biochemical screening and adrenal imaging. Etiologic treatment is curative, whereas antiarrhythmic therapy alone is insufficient. We review the previously published cases to contextualize this rare phenotype.