Abnormal QT interval variability in patients with multiple system atrophy

In a prospective study, we evaluated the hypothesis that QT variability is abnormal in multiple system atrophy. Time and frequency domain QT variability was assessed from 24-hour Holter monitoring. Three-channel Holter monitoring was performed in all subjects and was analyzed on a homemade analyzer. The 24-hour mean QT duration was similar in multiple system atrophy patients and in control subjects Unlike QT duration, several parameters of time and frequency domain QT variability were significantly increased in multiple system atrophy patients compared to healthy controls. Time domain measures of QT variability were significantly shorter while asleep than while awake in both groups. The nighttime % reduction in time-domain QT variability tended to be smaller in patients in comparison to control subjects, but this difference did not achieve statistical significance. This is the first reporting demonstrating that QT variability is abnormal in patients with multiple system atrophy