Introduction: Pheochromocytoma may present with ECG abnormalities as one of the few clues to the diagnosis.
Methods and Results: A 30-year-old woman presented with chest pain and a QTc of 525 ms. Four weeks later following a syncopal episode, her QTc was 660 ms. Short runs of monomorphic ventricular tachycardia were recorded. Investigations revealed an adrenal pheochromocytoma. Her QTc normalized after excision of the tumor. Comprehensive QT gene screening of KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2 was negative.
Conclusion: Pheochromocytoma may induce monomorphic VT and QT prolongation. The interaction of different catecholamines may have a compounding effect on cardiac repolarization.