Twenty-four-hour QT interval variability: increased QT variability during sleep in patients with panic disorder

Area of Science:

• Cardiology
• Psychiatry
• Autonomic Nervous System Function

Background:

• Beat-to-beat QT interval variability (QTV) serves as a noninvasive marker for cardiac repolarization lability.
• Elevated QTV is linked to sudden cardiac death and is observed in individuals with anxiety and depression.

Purpose of the Study:

• To investigate diurnal patterns of QTV in normal adults and patients with panic disorder.
• To assess if panic disorder affects the normal diurnal variation of cardiac repolarization.

Main Methods:

• Utilized 24-hour electrocardiogram (ECG) records from 32 healthy adults and 22 patients with panic disorder.
• Analyzed eight 5-minute ECG segments sampled at 1,000 Hz from each 24-hour recording.

Main Results:

• Patients with panic disorder exhibited significantly higher QTV measures during nighttime compared to controls.
• Findings indicate blunted diurnal changes in ventricular repolarization lability in panic disorder patients.
• A higher QT variability index was observed in patients during sleep.

Conclusions:

• Panic disorder is associated with altered diurnal regulation of cardiac repolarization.
• Blunted diurnal QTV changes in panic disorder may stem from increased cardiac sympathetic activity.
• These repolarization abnormalities could contribute to the heightened cardiac mortality risk in anxiety disorders.