PR Prolongation and Cardiac 123I-MIBG Uptake Reduction in Parkinson's Disease.

ABSTRACT

BACKGROUND: Cardiac 123I-metaiodobenzylguanidine scintigraphy (MIBG) previously demonstrated an uptake reduction in patients with Parkinson's disease (PD). However, epidemiologic research showed that electrocardiography (ECG) abnormalities occurred prior to motor signs in PD. Here we investigated whether the electrical conduction system of the heart was impaired in PD. METHODS: Clinical features, ECG and MIBG parameters were analyzed in 191 patients with PD, 42 with multiple system atrophy (MSA) and 124 normal controls (NL). RESULTS: The PR interval was significantly longer in patients with PD than in NL. The PR interval was significantly negatively correlated with early and delayed heart-to-mediastinum ratios in MIBG scintigraphy in PD and MSA patients. In 19 PD patients with PR prolongation, 17 patients also had abnormal MIBG findings, and the other 2 showed normal MIBG. CONCLUSIONS: The PR prolongation must show some sympathetic system abnormality because it is mainly controlled by the sympathetic nervous system. PR prolongation supports the objective biomarker value of MIBG for PD diagnosis.