Impaired heart rate variability and altered cardiac sympathovagal balance after antidepressant overdose

• Published in: European journal of clinical pharmacology 2008-11, Vol.64 (11), p.1037-1041
• Main Authors: Waring, W. S., Rhee, J. Y., Bateman, D. N., Leggett, G. E., Jamie, H.
• Format: Article
• Language: English
• Subjects: Adult; Antidepressants; Antidepressive Agents - poisoning; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Cardiac arrhythmia; Cardiac dysrhythmias; Cardiology. Vascular system; Drug Overdose; Female; Heart; Heart - drug effects; Heart - innervation; Heart rate; Heart Rate - drug effects; Heart Rate - physiology; Humans; Male; Medical sciences; Middle Aged; Pharmacodynamics; Pharmacology; Pharmacology. Drug treatments; Pharmacology/Toxicology; Prospective Studies; Sympathetic Nervous System - drug effects; Sympathetic Nervous System - physiopathology; Vagus Nerve - drug effects; Vagus Nerve - physiopathology
• ISSN: 0031-6970; 1432-1041
• DOI: 10.1007/s00228-008-0505-7

Purpose Antidepressant overdose may be associated with significant cardiotoxicity, and recent data have shown that acute toxic effects are associated with impaired heart rate variability. This study was designed to examine the feasibility of non-invasive heart rate variability recording in patients that present to hospital after deliberate antidepressant ingestion. Methods This was a prospective study of 72 consecutive patients attending the Emergency Department after deliberate antidepressant overdose and 72 age-matched patients that ingested paracetamol, as a control group. Single time-point continuous electrocardiographic recordings were used to allow spectral analyses of heart rate variability determined in low-frequency (LF) and high-frequency (HF) domains. The LF:HF ratio was used to represent overall sympathovagal cardiac activity. Results Antidepressant overdose was associated with reduced overall heart rate variability: 1329 vs. 2018 ms 2 ( P  = 0.0239 by Mann–Whitney test). Variability in the LF domain was higher (64.8 vs. 49.8, P  = 0.0006), whereas that in the HF domain was lower (24.3 vs. 36.4, P  = 0.0001), and the LF:HF ratio was higher in the antidepressant group (2.4 vs. 1.2, P  = 0.0003). Conclusions Antidepressant overdose is associated with impaired heart rate variability in a pattern consistent with excess cardiac sympathetic activity. Further work is required to establish the significance of these findings and to explore whether the impairment of heart rate variability may be used to predict the development of arrhythmia in this patient group.