Guidelines for Treating Cardiac Manifestations of Organophosphates Poisoning with Special Emphasis on Long QT and Torsades De Pointes

Abstract

Organophosphate poisoning may precipitate complex ventricular arrhythmias, a frequently overlooked and potentially lethal aspect of this condition. Acute effects consist of electrocardiographic ST-T segment changes and AV conduction disturbances of varying degrees, while long-lasting cardiac changes include QT prolongation, polymorphic tachycardia (“Torsades de Pointes”), and sudden cardiac death. Cardiac monitoring of organophosphate intoxicated patients for relatively long periods after the poisoning and early aggressive treatment of arrhythmias may be the clue to better survival. We present here a review of the literature with a focus on late cardiac arrhythmias (mainly “Torsades de pointes”), possible mechanisms, and treatment modalities, with special emphasis on postpoisoning monitoring for development of arrhythmias.

Key words :

• Arrhythmia
• Insecticides
• Medical Treatment
• Organophosphorous Compounds
• Torsades De Pointes

Notes

*SLUDGE syndrome: salivation, lacrimation, urination, defecation, GI (gastrointestinal) distress, and emesis.

^†Torsades de pointes refers to Ventricular Fibrillation characterized by polymorphic QRS complexes that change in amplitude and cycle length, giving the appearance of oscillations around the baseline. The electrocardiographic hallmark is polymorphic Ventricular Tachycardia preceded by marked QT prolongation. The clinical picture is characterized by recurrent syncope that may develop to Ventricular Fibrillation and sudden cardiac death.¹⁶

^‡ST–T changes in the ECG are seen in cases of myocardial ischemia and necrosis.

^§The Valsalva maneuver is mainly used to assess autonomic reflex control of cardiovascular function. It is performed by having the subject conduct a maximal, forced expiration against a closed glottis for 15 s.

**The Israeli hospital deployment plan for the management of chemical casualties charecterizes intoxication severity: The mildly intoxicated patient is ambulatory (able to walk). Moderate casualties are nonambulatory (unable to walk), whereas casualties in need of immediate intubation (respiratory insufficiency) are regarded as suffering from severe intoxication. This division is accepted by others as well.²⁸, ⁴¹