Acute psychosis leads to increased QT variability in patients suffering from schizophrenia.
Patients with schizophrenia have been reported to experience sudden cardiac death 3 times more likely than individuals from the general population. One important factor related to an increased risk of cardiac arrhythmias and sudden death is the prolongation of the QTc interval. This study examined whether acute psychosis might influence the beat-to-beat variability of the QT interval, which reflects effectively cardiac repolarization lability. High resolution electrocardiographic recordings were performed in 25 unmedicated patients suffering from acute schizophrenia and matched controls. From these, parameters of beat-to-beat heart rate and QT variability measures such as approximate entropy and QT variability index (QTvi) were calculated. Measures were correlated with the scale for the assessment of positive symptoms (SAPS) and negative symptoms (SANS). QTvi was significantly higher in patients with schizophrenia compared to controls. While QTvi correlated with the degree of delusions and hallucinations, no correlation with electrolyte concentrations was found. Approximate entropy of heart rate was decreased indicating reduced complexity and decreased vagal tone. In conclusion, increased QT variability in patients with schizophrenia indicates abnormal cardiac repolarization lability, which can result in serious cardiac arrhythmias. The correlation of positive symptoms with QT variability might indicate high sympathetic cardiac activity in these patients, which might be associated with increased cardiovascular mortality.
Bär
Karl-Jürgen
KJ
Department of Psychiatry, Friedrich-Schiller-University Jena, Philosophenweg 3, 07743 Jena, Germany. Karl-Juergen.Baer@med.uni-jena.de
Koschke
Mandy
M
Boettger
Michael Karl
MK
Berger
Sandy
S
Kabisch
Alexander
A
Sauer
Heinrich
H
Voss
Andreas
A
Yeragani
Vikram K
VK
D000208:Acute Disease; D000328:Adult; D001342:Autonomic Nervous System Diseases / Q000175:diagnosis / Q000453:epidemiology; D015897:Comorbidity; D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000209:etiology; D004569:Electroencephalography / Q000379:methods / Q000706:statistics & numerical data*; D019277:Entropy; D005260:Female; D006321:Heart / Q000294:innervation / Q000503:physiopathology; D006334:Heart Function Tests; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D008297:Male; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012559:Schizophrenia / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D014630:Vagus Nerve / Q000503:physiopathology