A hospital-based prospective study on analysis of axis deviation in patients with first attck of anterior wall myocardial infarction

Anne Varghese; G K Libu; N Sudhaya Kumar; V S Sumadevi

Anne Varghese Department of Physiology, MOSC Medical College, Kolenchery, Ernakulam ‑ 682 311, Kerala, India.
G K Libu Department of Community Medicine, Government Medical College, Kollam, Kerala, India.
N Sudhaya Kumar 2Department of Cardiology, Travancore Medical College, Kollam, Kerala, India.
V S Sumadevi Department of Physiology, Dr. SM CSI Medical College, Thiruvananthapuram, Kerala, India.

Keywords: Arrhythmias, axis shift, first myocardial infarction, left ventricular failure, mean electrical axis, mortality

Abstract

Background and Aim: Electrocardiography is a very important investigative procedure that can be performed easily and quickly. A baseline investigation in the evaluation of cardiac status, one practical application of electrocardiogram, is axis determination, which is very useful in diagnosis and prognostication in patients with acute coronary syndromes. Therefore, the aim of this study is to calculate the mean QRS axis using the hexaxial reference frame in patients with the first acute myocardial infarction (MI) and to see if any relation exists between the axis deviation and the clinical outcome. Methods: It is a hospital‑based cross‑sectional study conducted in 200 patients with the first attack of anterior wall MI with respect to a control group consisting 162 normal subjects. The mean frontal plane QRS axis was found using the hexaxial reference frame. Student’s t‑test and Pearson Chi‑square test were used for statistical analysis of data. Results: Twenty‑five percent of the study subjects had left axis deviation, and 3.5% had right axis deviation. About 15% of the subjects developed left ventricular failure (LVF), of whom 19 (63%) were males and 11 (37%) were females. This difference between males and females was found to be statistically significant. The frequency of occurrence of LVF in females >61 years of age and that of arrhythmias in females 41–50 years was significantly higher. Conclusion: The statistically significant difference between the mean electrical axis (MEA) of the study subjects when compared with the controls is not unexpected as MI produces deviation of the MEA. There was a tendency for a greater axis shift (30°) in patients who developed LVF; however, this shift was not found to be statistically significant.