Prognostic value of long QT interval in acute and severe organophosphate poisoning

Abstract

Introduction: Suicidal poisoning with organophosphorus (OP) pesticides is common, particularly from rural areas. This highlights the importance of determining an OP poisoning prognosis to decide how aggressive treatment should be. There are reports suggesting a relationship between prolonged corrected QT (QTC) interval and the severity of poisoning. We aimed to evaluate the prognostic utility of this clinical tool in OP poisoning (OPP) patients.Methods: Patients with the primary diagnosis of OPP who were admitted to the intensive care unit (ICU) of Loghman-Hakim Hospital Poison Centre (LHHPC) were the subjects of this prospective study. Cholinesterase (CE) activity and the QTC interval was determined for each patient using the Bazett formula and considering <440 msec as normal. Comparative outcomes of the study were duration of both hospitalization and mechanical ventilation, serum CE activity on admission and its daily level, total amount of atropine administered, analysis of the QT and QTC intervals in the primary ECG on admission and at the end of hospitalization, and rate of mortality.Results: The study included 42 patients with a diagnosis of OPP. The mean age of the patients was 32, ranged from 12 to 81 years old. The mortality rate was 37.5%. There was no significant difference between two groups (prolonged and normal QTC intervals) according to gender and age (p = .491 and p = .133, respectively). The CE level for long and normal QTC interval groups was 3.90 Ϯ 0.33 kU/L vs. 4.41 Ϯ 0.23 kU/L, respectively. The mortality rate in the long QTC group was significantly higher than that of the normal QTC group (p = .044). Moreover, the average period of hospitalization in patients with prolonged QTC interval was higher than the other group (p = .02). The average atropine required to control the muscarinic signs and symptoms such as salivation, bronchorrehea, and miosis in patients with prolonged QTC interval was 38.60 mg; in patients with normal QTC interval it was 20.02 mg (p = .013).Conclusion: QTC interval prolongation may have prognostic value in OPP.

Sarin Causes Autonomic Imbalance and Cardiomyopathy

“…The QTc segment of ECG is often used as a biomarker of susceptibility to sudden arrhythmias and QTc prolongation has been reported upon acute OP poisoning in humans. 25 In addition, rats given a convulsive FIGURE 8. Cardiac histology and immunohistochemistry: evidence of cardiac remodeling: Sarin-treated mice showed significantly increased heart to BW ratio (A) LV cardiomyocytes were larger in sarin-treated mice as seen in the H & E stained sections and the image analysis data (B).…”

Adverse effects of organophosphorus pesticides on the liver: a brief summary of four decades of research

“…These pesticides are readily available on the market. Suicidal poisoning with OPs is common, particularly in rural areas (4). Acute poisoning with OPs is a global threat to human health that causes more than 100,000 deaths a year (5,6).…”

Environmental Toxins and the Heart

“…277,278,280À282 The severity of systemic poisoning may be estimated by measuring plasma or urine organophosphate concentration, cholinesterase activity, and serum ß-glucuronidase concentration. 279,283 Various life-threatening arrhythmias may occur, including bradycardia, atrioventricular and intraventricular block, atrial fibrillation, and polymorphic ventricular tachycardia (so-called torsades de pointes). 277,280,282,284À286 ST-segment abnormalities may occur acutely and persist for weeks after drug exposure, 280 and life-threatening arrhythmias may occur as late as 20 days after exposure.…”