P3-21: High prevalence of cardiac electric abnormalities in patients with pheochromocytomas and secreting paragangliomas

Abstract

Background Pheochromocytomas and paragangliomas (PPGLs) are catecholamine-producing tumours of chromaffin cells of the adrenal medulla and extra-adrenal paraganglia. Besides hypertension, they can be at the origin of a wide range of cardiovascular manifestations, including cardiac electric abnormalities such as long QT interval, ventricular tachycardia and torsades de pointe. However, knowledge about PPGL-related arrhythmias is scarce and mostly derived from case reports. The aim of our study was to evaluate the prevalence, nature and reversibility of cardiac electric changes and arrhythmias in patients with PPGLs. Methods We retrospectively reviewed the medical records of patients diagnosed with PPGLs at the Cliniques Universitaires Saint-Luc (Brussels) from 1995 to 2015. All patients with secreting PPGLs in whom an electrocardiogram (ECG) was available at the time of diagnosis were eligible. Results Forty-five patients with secreting PPGLs were identified. The mean age at diagnosis was 48 years (12-72), 40% of patients (n=18) were males and location of the tumour was adrenal in 87% of cases (n=39). An ECG was available in 31 patients at the time of diagnosis. Of these, 77% (n=24) presented at least one electric abnormality. While a positive Sokolow index was found in only 3 patients, non-specific ST-abnormalities were documented in 14 patients (45%), a T-wave inversion in at least two precordial leads in 9 (29%) and a predominant U- wave in 7 patients (23%) Furthermore, a corrected QT interval prolongation (>450ms) was present in 55% of patients (n=17, mean: 528ms±93ms). In all nine patients with QTc prolongation at diagnosis in whom a follow-up ECG was available, QTc normalized after surgery (QTc.: 420±20ms after surgery vs. 523±50ms at baseline, p 600ms), two patients presented with polymorphic ventricular tachycardia related to a long QT interval at diagnosis that never recurred after surgery, and one patient was diagnosed with paroxystic atrial fibrillation, which resolved after tumour removal. Conclusions We report a high prevalence (77%) of cardiac electric abnormalities in a retrospective monocentric series of PPGLs. While our findings need confirmation in larger, prospective cohorts, they strongly suggest that cardiac electric abnormalities are an underrecognized, frequent complication of catecholamine excess in patients with PPGLs, and should be an integral part of the work-up and management of these patients.