A Study on Electrocardiographic Changes in Acute Organophosphorus Poisoning and Its Association with Prognosis in Tertiary Care Hospital

BACKGROUND: Organophosphorus poisoning by intentional or accidental exposure is a major health problem in rural world. OP compounds act by inhibiting the enzyme Acetyl cholinesterase leading to symptoms of cholinergic excess. OP compounds could cause various electrocardiographic changes and cardiac complications like hypertension, hypotension and arrhythmias which are less studied. OBJECTIVE: To study the frequency of electrocardiographic changes in acute organophosphorus poisoning and its association with prognosis and outcome in those patients. METHODOLOGY: This is a prospective cross-sectional study conducted in Kanyakumari Government Medical College including 80 patients who fulfilled the inclusion and exclusion criteria. Patients who took OP compounds mixed with other compounds, doubtful diagnosis, those received atropine before admission, prior cardiac disease, those with long QT syndrome, those taking the drugs prolonging QT interval were excluded. A baseline ECG was recorded immediately after admission and serial ECGs at 12th hourly, or as early as possible if arrhythmias are found. ECGs were analysed for rate, rhythm, axis, ST-T changes, PR and QTc interval calculation. RESULTS: Among the study population, 62 patients survived and 18 patients expired. Various ECG changes noted either in isolation or in association with other changes. Overall, QTc prolongation was seen in 39 cases(48.75%), followed by T wave inversion in 22 cases(27.5%), low voltage complexes in 16 cases(20%), extra systole in 10 cases(12.5%), ventricular tachycardia in 8 cases(10%), atrial fibrillation in 4 cases(5%), ST elevation in 3 cases(3.75%), ST depression and PR prolongation in 1 case(1.25%) each. Among the isolated ECG changes QTc prolongation tops the list with 17 cases followed by T wave inversion 13 cases and low voltage complex in 11 cases. By statistical methods, none of the ECG changes were significantly associated with outcome of patients. Among the expired cases, 12 had QTc prolongation. As overall, ventricular tachycardia was seen in 7 patients with QTc prolongation. CONCLUSION: Though ECG changes are frequently associated with organophosphorus poisoning, none of the isolated ECG changes were significantly associated with outcome of patients. However, due to increased frequency of arrhythmias like ventricular tachycardia in patients with QTc prolongation, management of patients with ECG changes in intensive cardiac care unit will reduce mortality and morbidity