title: A meta-analysis of prognostic indicators to predict seizures, arrhythmias or death after tricyclic antidepressant overdose.
abstract: OBJECTIVE
  To systematically review and summarize studies on the accuracy of ECG and tricyclic antidepressant (TCA) concentration as prognostic indicators of the risk of seizures, ventricular arrhythmia (VA) or death in patients with TCA overdose.
  
  
  METHODS
  Articles were identified with MedLine and Cochrane register of controlled clinical trials searches and review of medical toxicology textbooks. Quality of the included studies was assessed. Pooled estimates of sensitivity, specificity, likelihood ratios and Summary Receiver Operating Characteristics (SROC) curves were generated.
  
  
  RESULTS
  A total of 18 studies were included in the analysis. The pooled sensitivity (Se) and specificity (Sp) of the QRS for predicting seizures were 0.69 [95% CI 0.57-0.78] and 0.69 [95% CI 0.58-0.78] as compared to 0.75 [95% CI 0.61-0.85] and 0.72 [95% CI 0.61-0.81] for the TCA concentration. The Se and Sp of the QRS to predict VA were 0.79 [95% CI 0.58-0.91] and 0.46 [95% CI 0.35-0.59] compared to 0.78 [95% CI 0.56-0.90] and 0.57 [95% CI 0.46-0.67] for the TCA concentration. The Se and Sp of the QRS to predict death were 0.81 [95% CI 0.54-0.94] and 0.62 [95% CI 0.55-0.68] compared to 0.76 [95% CI 0.49-0.91] and 0.60 [95% CI 0.47-0.72] for the TCA concentration. Very few studies evaluated the accuracy of QTc, T 40 ms axis and the R/S ratio.
  
  
  CONCLUSIONS
  Overall, the studies suggested that the ECG and TCA concentration have similar but relatively poor performance for predicting complications, such as seizures, VA or death, associated with TCA overdose.
authors.affiliation: Division of Emergency Medicine and Clinical Pharmacology, Department of Pediatrics, Hôpital Ste-Justine, Université de Montréal, Montréal, Canada. benoit.bailey@umontreal.ca
authors.forename: Benoit
authors.initials: B
authors.lastname: Bailey
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Buckley
authors.forename: Devendra K
authors.initials: DK
authors.lastname: Amre
mesh_terms: D000929:Antidepressive Agents, Tricyclic / Q000506:poisoning*; D001145:Arrhythmias, Cardiac / Q000139:chemically induced* / Q000503:physiopathology; D004562:Electrocardiography / Q000187:drug effects; D006801:Humans; D011041:Poisoning / Q000401:mortality; D011379:Prognosis; D011786:Quality Control; D012107:Research Design; D012640:Seizures / Q000139:chemically induced* / Q000503:physiopathology
chemical_list: D000929:Antidepressive Agents, Tricyclic