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Shiyovich A, Matot R, Elyagon S, Liel-Cohen N, Rosman Y, Shrot S, Kassirer M, Katz A, Etzion Y. QT Prolongation as an Isolated Long-Term Cardiac Manifestation of Dichlorvos Organophosphate Poisoning in Rats. Cardiovasc Toxicol 2019; 18:24-32. [PMID: 28510081 DOI: 10.1007/s12012-017-9409-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Organophosphates (OP) are used extensively as pesticides and as chemical weapons. Cardiotoxicity is a major concern in survivors of the acute poisoning. To characterize the delayed cardiac effects of OP, rats were poisoned by intraperitoneal administration of dichlorvos. In group I, poisoning (0.25-, 0.75-, 1.4-LD50) was followed by application of atropine and obidoxime. In group II, poisoning (0.35-, 0.5-LD50) was done without antidotes. Cardiac evaluation included electrocardiography and echocardiography 2- and 6-week post-exposure, arrhythmia susceptibility following administration of Isoproterenol (150 mcg/kg), and histological evaluation. All poisoned animals displayed cholinergic symptoms. In group I, all animals exposed to 1.4-LD50 (n = 3) had profound convulsions and died despite antidote treatment. However, in the lower doses, all animals survived and no cardiac abnormalities were noted during follow-up. In group II, six animals had convulsions and died. Surviving animals had mild but significant prolongation of corrected QT at both 2 and 6 weeks, compared to shams. There were no notable echocardiographic, gravimetric, or histological differences between poisoned and sham animals. Our data indicate that dichlorvos poisoning is associated with QT prolongation without anatomical or histopathological abnormalities. This new model can be used to elaborate the molecular mechanism\s of QT prolongation following OP poisoning.
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Affiliation(s)
- Arthur Shiyovich
- Medical Corps HQ, IDF, P.O. Box 02149, Tel Hashomer Base, Ramat-Gan, Israel
| | - Ran Matot
- Cardiac Arrhythmia Research Laboratory, Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 653, 84105, Beer-Sheva, Israel
| | - Sigal Elyagon
- Cardiac Arrhythmia Research Laboratory, Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 653, 84105, Beer-Sheva, Israel
| | - Noah Liel-Cohen
- Department of Cardiology, Soroka University Medical Center and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yossi Rosman
- Medical Corps HQ, IDF, P.O. Box 02149, Tel Hashomer Base, Ramat-Gan, Israel
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Shai Shrot
- Medical Corps HQ, IDF, P.O. Box 02149, Tel Hashomer Base, Ramat-Gan, Israel
| | - Michael Kassirer
- Medical Corps HQ, IDF, P.O. Box 02149, Tel Hashomer Base, Ramat-Gan, Israel
- Pulmonary Institute, Soroka University Medical Center and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Amos Katz
- Department of Cardiology, Barzilai Medical Center, Ashkelon and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yoram Etzion
- Cardiac Arrhythmia Research Laboratory, Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 653, 84105, Beer-Sheva, Israel.
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Tan HL, Hou CJ, Lauer MR, Sung RJ. Electrophysiologic mechanisms of the long QT interval syndromes and torsade de pointes. Ann Intern Med 1995; 122:701-14. [PMID: 7702233 DOI: 10.7326/0003-4819-122-9-199505010-00009] [Citation(s) in RCA: 173] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
PURPOSE To review the current understanding of the mechanisms and treatment of the long QT interval syndromes and torsade de pointes. DATA SOURCES Personal databases of the authors and a search of the MEDLINE database from 1966 to 1994. STUDY SELECTION Experimental and clinical studies and topical reviews on the electrophysiologic mechanisms and treatment of torsade de pointes were analyzed. RESULTS The long QT interval syndromes have been classified into acquired and hereditary forms, both of which are associated with a characteristic type of life-threatening polymorphic ventricular tachycardia called torsade de pointes. The acquired form is caused by various agents and conditions that reduce the magnitude of outward repolarizing K+ currents, enhance inward depolarizing Na+ or Ca2+ currents, or both, thereby triggering the development of early afterdepolarizations that initiate the tachyarrhythmia. The hereditary form appears to result from an abnormal response to adrenergic or sympathetic nervous system stimulation. At least some cases of the hereditary long QT interval syndromes may result from a single gene defect that alters the intracellular regulatory proteins responsible for the modulation of K+ channel function. Treatment of the acquired form is primarily directed at identifying and withdrawing the offending agent, although emergent therapy using maneuvers and agents that favorably modulate transmembrane ion currents can be lifesaving. In torsade de pointes associated with the hereditary long QT interval syndromes, early diagnosis leading to treatments designed to both shorten the QT interval and block the beta-adrenergic-induced instability of the QT interval is essential. CONCLUSIONS The long QT interval syndromes and torsade de pointes are potentially life-threatening conditions caused by various agents, conditions, and genetic defects. The mechanisms responsible for these conditions and available treatment options for them are reviewed.
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Affiliation(s)
- H L Tan
- Stanford University School of Medicine, California, USA
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