57-01: Electrical remodeling of repolarization abnormality after surgical treatment in pheochromocytoma: a retrospective analysis

Abstract

Background: Pheochromocytoma, a rare neuroendocrine tumor, clinically characterized by high blood pressure, palpitations and headache, is often associated with abnormalities of the ventricular repolarization phase(1), in particular with the presence of U wave(2). This dispersion of ventricular repolarization is the basis of ventricular arrhythmias. Method: We analyzed a series of ECG of 10 patients (9M/1F, 43 ± 18 years aged) affected by pheochromocytoma, collected before and after surgical treatment. We evaluated hear rate (HR), P wave, PR, QRS, QTc, number of U wave present in each twelve lead ECG, electrolytes values, systemic blood pressure and 24-hour urinary excretion of 3-methoxytyramine, normetanephrine and metanephrine. Results: All patients were in sinus rhythm, without any brunch block. There was no difference in term of electrolytes, duration of P wave, PR, QRS, QTc, HR. We found clear presence of U wave in all patients before surgery, while there was a significative reduction/suppression in number of U wave counted in 12 lead ECG after surgery. After surgery, as expected, we observed a clear drop in systemic blood pressure and 3-methoxytyramine, normetanephrine and metanephrine urinary level. We observed a linear correlation between number of U wave in 12 lead ECG and 3-methoxytyramine levels (r= 0.615, p =0.015). Conclusion: A careful analysis of the electrocardiogram is mandatory in patients with hypertensive crisis, particularly the phase of ventricular repolarization characterized by U wave; this finding should lead the clinician to suspect the diagnosis of pheochromocytoma.