title: How valuable is P-wave dispersion in the determination of carboxyhemoglobin levels?
abstract: OBJECTIVE
  To determine whether or not wave/interval dispersions in electrocardiography (ECG) are increased, and to define whether wave and interval dispersions are correlated with carboxyhemoglobin (COHb) levels.
  
  
  METHODS
  ECG, complete blood count, and biochemical parameters were taken from 87 patients with carbon monoxide (CO) poisoning as well as 90 control patients with similar age, gender, and body mass index distribution. COHb levels were recorded in CO-poisoning patients. The COHb levels and the relationships with ECG parameters were studied.
  
  
  RESULTS
  Pmax, Pmin, Pd, PRmax, PRmin, PRd, QTmax, QTmin, QTd, cQTmax, cQTmin, cQTd, Tmax, Tmin, and Td in ECG were higher in intoxicated patients than the control group (p < 0.05 for all). Pearson's correlation analyses showed moderately significant positive correlations between COHb level and Pmax (r = 0.224; p = 0.037) and Pd (r = 0.222; p = 0.039). The receiver-operator characteristic (ROC) curve showed that a Pd value of 38 ms determined by ECG separates patients with a COHb ≥ 20% with area under the ROC curve of 0.78 (95%CI = 0.71-0.83), a sensitivity of 67.9% (95%CI = 59.4-75.6), a specificity of 95% (95%CI = 83.0-99.2], a positive predictive value of 97.9% (95%CI = 92.5-99.7), and a negative predictive value of 46.3% (95%CI = 35.3-57.7.)
  
  
  CONCLUSIONS
  A significant increase in wave/interval dispersions in the ECG of CO-poisoning patients compared with controls may show that not only a part is affected but both atrium and the ventricles as a whole are affected by hypoxic ischemia. When COHb levels of the patients are unavailable, P dispersion on ECG may show CO poisoning level of the patient.
authors.affiliation: 1Department of Forensic Medicine, Faculty of Medicine, Ataturk University, Erzurum, Turkey.
authors.forename: M T
authors.initials: MT
authors.lastname: Sener
authors.forename: Y
authors.initials: Y
authors.lastname: Anci
authors.forename: K
authors.initials: K
authors.lastname: Kalkan
authors.forename: M Z
authors.initials: MZ
authors.lastname: Kir
authors.forename: M
authors.initials: M
authors.lastname: Emet
mesh_terms: D000328:Adult; D002249:Carbon Monoxide Poisoning / Q000097:blood* / Q000503:physiopathology; D002263:Carboxyhemoglobin / Q000032:analysis*; D016022:Case-Control Studies; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve
chemical_list: D002263:Carboxyhemoglobin
keywords: CO poisoning; Carboxyhemoglobin; P dispersion; carbon monoxide; electrocardiography