Prognostic implications of shift in electrical axis in acute anterior wall myocardial infarction

Dr. Cicy Bastian; Dr. Dolly Mathew; Dr. Devarajan Karimpanmavil Ayyappan; Dr. N Sudhaya Kumar

Prognostic implications of shift in electrical axis in acute anterior wall myocardial infarction

Authors
Dr. Cicy Bastian, Dr. Dolly Mathew, Dr. Devarajan Karimpanmavil Ayyappan, Dr. N Sudhaya Kumar

Abstract
Introduction: The long term and short term prognosis of a patient presenting with acute myocardial infarction depends on many factors. The established prognostic markers include clinical, biochemical, electrocardiographic, echocardiographic and various types of imaging modalities. The existing prognostic indicators have some limitations. So there is always a search for simpler and more reliable methods for diagnosis and prognostication of acute myocardial infarction. Clinical markers include age of the patient, previous history of myocardial infarction, hemodynamic complications like congestive heart failure, new mitral regurgitation or hypotension and Left ventricular dysfunction. Serum markers of cardiac damage like Creatine kinase (CK), CK isoenzymes (CK MB) are important biomarkers of myocardial necrosis. Myoglobin and cardiac troponins are other useful markers for prognostication. In patients with chest pain compatible with myocardial infarction, echocardiography is a useful diagnostic tool to quantify the area of infarction. Electrocardiogram (ECG) provides critical information for both diagnosis and prognosis after acute myocardial infarction. During an episode of acute myocardial infarction, there can be shift in mean QRS electrical axis due to various reasons with or without fascicular blocks. The aim of the study was to find out whether there is any correlation between the shift in mean QRS electrical axis and inhospital outcome in patients with first ST elevation anterior wall myocardial infarction.

Methods: A total of 180 patients with first acute anterior ST elevation myocardial infarction(STEMI) were included in the study. ECG was taken at admission, 90 minutes, 12 hours, 24 hours and 48 hours post thrombolysis. QRS axis was determined by bedside method and graph paper method.

Results: It was found that there is a shift in mean QRS axis from baseline ECG in a large proportion of patients with acute anterior Myocardial infarction. There was an increase in incidence of major arrhythmias in patients with leftward axis shift. There was an insignificant increase in the primary and secondary endpoints in the group with leftward axis shift compared to those with rightward axis shift.

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