Reversible Increases in Qt Dispersion and P Wave Dispersion during Carbon Monoxide Intoxication

Objectives Carbon monoxide (CO) is a potent myocardial toxin. We investigated the association between acute CO intoxication and electrocardiographic QT interval (QTmax/QTmin), corrected QT interval (cQTmax/cQTmin), QT dispersion (QTd) and corrected QT dispersion (cQTd), P wave duration (Pmax/Pmin) and P wave dispersion (Pd), which were known as predictors of ventricular arrhythmias, atrial fibrillation and sudden death. Methods Electrocardiography with 12-leads and blood gas were taken from 65 patients with CO intoxication as well as 65 control patients with similar age and gender distribution at the admission time to the emergency department and at the 4th hour post-therapy. The carboxyhaemoglobin (COHb) levels and the relationships with electrocardiographic parameters were studied. Results The mean COHb levels were 21.43±6.85% and 1.37±0.98% in intoxicated patients and in the control group respectively. QTmax, QTd, cQTmax, cQTd, Pmax, and Pd were found significantly higher in intoxicated patients when compared to the control group (373.98±40.35 vs. 355.98±32.88, p=0.006; 49.29±22.66 vs. 20.43±11.16, p<0.001; 455.38±30.72 vs. 419.57±22.27, p<0.001; 60.88±25.99 vs. 25.75±13.13, p<0.001; 107.91±13.28 vs. 96.65±12.65, p<0.001, 46.85±13.49 vs. 35.22±10.07, p<0.001 respectively). In Pearson correlation analysis, there were significant correlations between COHb level and QTmax, QTd, cQTmax, cQTd, Pmax and Pd (r=0.211, p=0.016; r=0.610, p<0.001; r=0.599, p<0.001; r=0.628, p<0.001; r=0.458, p<0.001; r=0.414, p<0.001 respectively). Conclusion A correlation between reversible increases in QTd, cQTmax, cQTd, Pmax and Pd in the electrocardiogram and COHb can be observed in acute CO intoxication patients.