Cardiac abnormalities in acute organophosphate poisoning.
BACKGROUND
Potentially lethal cardiac complications can occur in patients with acute organophosphate poisoning (OPP) and may be overlooked.


METHODS
Thirty-six patients with acute OPP were studied. Clinical features and the nature of compound involved were recorded. The QT interval was plotted against heart rate to determine the risk for Torsades de Pointes using the Fossa nomogram. Echocardiography was undertaken in 29 patients. Twenty-four-hour Holter monitoring was performed on day 1 in five patients. Thirteen died. Necropsy was performed and hearts were studied both grossly and microscopically.


RESULTS
Gross examination of the heart in 13 cases revealed cardiac discoloration or blotchiness in 12, patchy pericarditis in six, auricular thrombus in six, right ventricular hypertrophy in four, and dilatation in three. On histopathology, all 13 cases had myocardial interstitial edema and vascular congestion, eight had patchy interstitial inflammation, two had patchy myocarditis, and six had a mural thrombus. Sinus tachycardia was the most common electrocardiographic abnormality. The others were corrected QT interval prolongation, ST-T changes, U waves, and ventricular premature contractions. Echocardiography in 29 patients showed minor abnormalities in 10. On Holter monitoring, episodic tachycardia and ST-T changes were observed in four, QT prolongation in three, and episodic bradycardia in two.


CONCLUSIONS
Patchy myocardial involvement as a result of direct cardiac toxicity could be one of the factors responsible for serious cardiac complications. As myocardial involvement is patchy, it may not be manifest clinically or on echocardiography. Continuous cardiac monitoring should be undertaken to detect dynamic cardiac changes.
Anand
S
S
Department of Internal Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Singh
Surjit
S
Nahar Saikia
Uma
U
Bhalla
Ashish
A
Paul Sharma
Yash
Y
Singh
Dalbir
D
D000293:Adolescent; D000328:Adult; D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000628:therapy; D018660:Blood Pressure Monitoring, Ambulatory; D001831:Body Temperature; D002801:Cholinesterase Reactivators / Q000627:therapeutic use; D004562:Electrocardiography; D005260:Female; D006331:Heart Diseases / Q000139:chemically induced* / Q000000981:diagnostic imaging / Q000503:physiopathology; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007306:Insecticides / Q000506:poisoning; D008297:Male; D008875:Middle Aged; D062025:Organophosphate Poisoning; D011220:Pralidoxime Compounds / Q000627:therapeutic use; D011446:Prospective Studies; D011859:Radiography; D015656:Respiratory Mechanics / Q000187:drug effects; D017741:Survivors; D055815:Young Adult
D002801:Cholinesterase Reactivators; D007306:Insecticides; D011220:Pralidoxime Compounds; C028797:pralidoxime