Impact of Pheochromocytoma on Left Ventricular Hypertrophy and QTc Prolongation: Comparison with Takotsubo Cardiomyopathy

Background and Objectives: Excessive catecholamine causes the alteration of cardiac structure and function. This study evaluated if there is any difference in left ventricular hypertrophy (LVH) and QTc prolongation in conditions with pheochromocytoma and Takotsubo cardiomyopathy (TC). Subjects and Methods: We reviewed the medical records of 20 pheochromocytoma patients for cardiovascular events prior to diagnosis. The patient's clinical history and electrocardiographic and echocardiographic findings were compared to those of 20 patients diagnosed with TC. Results: Left ventricular (LV) mass index ($133.3{\pm}37.8$ vs. $113.3{\pm}17.3$, p=0.031), relative wall thickness ($0.55{\pm}0.15$ vs. $0.47{\pm}0.07$, p=032) and elevated blood pressure (BP) were more prominent in pheochromocytoma compared to TC. The mean creatinine kinase-MB elevation, reduced LV systolic function and ST segment changes were more prominent in the TC group compared to the pheochromocytoma groups (all p<0.05). The prevalence of QTc prolongation was high in patients with pheochromocytoma (45%) and TC (55%), and TC male patients appeared to have a more prolonged QTc interval. Urine epinephrine (r=0.844, p=0.004) and norepinephrine level (r=0.782, p=0.013) were significantly correlated with LV mass index, and the predictors for the QTc prolongation were male gender and the presence of LVH. Conclusion: A prolonged QTc was prominent in pheochromocytoma and TC regardless of BP and systolic LV function, and LVH was more prominent in pheochromocytoma than TC.