Outcomes of screening Parkinson's patients for QTc prolongation

Abstract

Background: Parkinson's disease (PD) patients are commonly prescribed medication that has recently been associated with QTc prolongation on electrocardiograms (ECG). In addition, research suggests that PD patients may be more at risk of QTc prolongation.

Objective: To evaluate the outcomes of screening PD patients for QTc prolongation.

Methods: ECG analysis of PD patients attending for routine outpatient PD review in 2012 who were prescribed medication that could potentially prolong their QTc interval. We noted prescribing changes and any repeat ECG findings. We also reviewed any recent ECGs of clinic patients not on QTc prolonging medication.

Results: A third of our PD clinic patients (63/192) were prescribed QTc prolonging medication. Of these 61/63 (97%) ECGs were available. 20/61 (33%) showed QTc prolongation. 6/20 (30%) had significant prolongation >500 ms. 18/20 (90%) patients had medication changes made, and of the 12/18 (67%) ECGs repeated in this group all improved with 11 demonstrating normalisation of the QTc interval. Of the 51 available ECGs in patients not prescribed QTc prolonging medication 3/51 (6%) showed QTc prolongation. Statistical analysis showed that QTc prolongation was significantly associated with the prescription of QTC prolonging medication and stage of PD.

Conclusion: QTc prolongation in PD patients caused by medication is a major modifiable risk factor. A routine ECG should be considered if a PD patient is currently prescribed medication that can prolong the QTc interval. Also consideration should be given to performing this simple test prior to commencing QTc prolonging medication.

Keywords: Medication; Parkinson's disease; QTc prolongation; Risk factors.