AB0485 INTRAVENOUS HIGH DOSE GLUCOCORTICOIDS CAUSE PROLONGATION OF QT INTERVAL IN CONNECTIVE TISSUE DISEASE PATIENTS EXCEPT ANTI-RO POSITIVE SUBGROUP

Abstract

Background: Recent literature indicates that anti-Ro antibodies may be associated with prolongation of corrected QT (QTc) interval in the adult patients with connective tissue diseases. Moreover, glucocorticoids (frequently used in the therapy) are known to probably induce electrocardiographic changes including prolongation of QT interval. Prolongation of QTc interval is a risk factor for malignant ventricular arrhythmias. We hypothetised that patients with anti-Ro positivity have a higher risk of QT prolongation especially in the case of high dose intravenous glucocorticoids (IVGC) treatment. Objectives: The aim of the study was to analyse risk of QTc interval prolongation in anti-Ro and anti-La positive patients before and after high dose IVGC treatment in patients with connective tissue diseases. Methods: We performed a retrospective study of 115 patients (21 males), mean age of 48±14.7 years, range 19-78 years with connective tissue disease. Anti-Ro antibodies were examined in all patients before IVGC treatment. The patients were given 5x1000 mg methyprednisolon i.v. during five consecutive days. ECG recording was performed at baseline and after IVGC. The QT intervals were measured in each of 12-lead standard ECGs from two consecutive cycles. The QT intervals were measured from the onset of QRS complex to the end of the T wave by the means of a tangential method. Fridericia formula was used to obtain heart rate-corrected values for QT intervals. Results: Comparing patients with anti-Ro positivity (n=39; 33.9%) and anti Ro-negativity (n=76, 66.1%), we found insignificant difference in QTc interval; QTcRo+ =417.2±28.4ms and QTcRo- =420,8±26.4ms (P=0.51), respectively. Admission of IVGC showed significant prolongation of QTc in all patients, mean QTc1 before treatment was 399.4±26.2ms, and QTc2 after therapy 412.7±27.2ms, P=0.00021. On the other hand, anti-Ro and anti-La positivity showed shorter QTc interval 391±18.7ms, to compare patients without these antibodies QTc=414.8±25.7ms, P=0.019 after treatment. Conclusion: IVGC treatment significantly prolongs QT interval. Prolongation of QT over 445 ms was found in nine patients, but ventricular arrythmias were not observed. The presence of anti-Ro and anti-La antibodies did not show QT prolongation. Therefore, shortening of QT/QTc iterval needs further confirmation. Motivated by this experience, we consider ECG monitoring and careful observation of patients during IVGC treatment. Acknowledgement: Charles University research projects [PROGRES Q40-15, PROGRES Q47] Disclosure of Interests: None declared