Background: Cardiac death caused by malignant arrhythmias is very prevalent. Prolongation
of the QT interval is a relevant aspect in arrhythmia mechanisms. Prior studies have
revealed that the QTc interval could be shortened by cortisone. Moreover, in an animal
model of long QT syndrome, cortisone treatment shortens the ventricular action potential
duration. The present study investigated the effect of methylprednisolone (MPS) on
the QTc interval in cardiovascularly healthy humans. Methods: Patients who had just
been diagnosed with multiple sclerosis receiving MPS therapy were analysed prospectively.
Demographic data, laboratory values, anti-arrhythmic medication and baseline and follow-up
ECGs were extracted from the patients' medical records. Results: Seventy-eight patients
were included. The mean +/- standard deviation age was 47 +/- 15 years. The values
of the electrolytes were normal. All patients were treated with MPS for 3 or 5 days.
The heart rate increased at the beginning of MPS therapy and decreased during the
subsequent period. ECG measurements showed that the QTc interval was prolonged at
the beginning of MPS therapy and shortened over the course of treatment. The longest
QTc intervals were obtained by calculation with Bazett's formula. Conclusions: In
humans, cortisone shortens the QTc interval over time. The analysis indicates a cumulative
effect of cortisone that lasts longer. The results of our pilot study reveal that
cortisone might be added to therapeutic strategies in patients with long QT syndromes.
Further clinical studies have to be carried out to analyze potential clinical options.
