Jerry M. Obaldo
Background: Myocardial ischemia is a well-known cause of heart failure accounting for 24% according to the Framingham and Framingham Offspring cohort study between 1970-1999. Another infrequent, but serious complication of myocardial infarction are life threatening ventricular arrhythmias such as ventricular tachycardia and ventricular fibrillation accounting for 10% based on GUSTO 1 trial. These arrhythmias are due to development of scarred tissue and are related to increase mortality and morbidity. Injured tissue around an infarct scar resulted in RSR' pattern of the QRS complex known as fragmented QRS. The objective of this study is to determine the association of fQRS on ECG and the presence of myocardial fibrosis on MPI.
Method: This is a cross-sectional study conducted at the PHC over a period of 12 months from July 2015-July 2016. All patients >19 years old, assessed to have CAD or a CAD suspect, with or without fQRS in the ECG who underwent MPI were included in the study. Exclusion criteria were patients with valve disease, wide QRS complex >120 ms, pacemaker and atrial fibrillation. The consultant advisers officially interpreted all ECG and MPI results independently.
Results: A total of 91 subjects were enrolled. Fragmented QRS was present in 64% (n=58). The mean age of patients with fQRS is 54 +10. The total population was divided into 2 groups: fQRS (+) group and fQRS (-) group. There was no significant difference between 2 groups in terms of age, BP, Dyslipidemia, as well as ECG findings like QTc, PR and HR. Fragmented QRS were more common in male (83%), known diabetic (50%), with prior MI (50%), current smoker (43%) and with ECG finding of longer QRS time. Logistic regression analysis with the presence of fQRS in the ECG and the existence of fibrosis on MPI showed that fQRS was significantly associated with myocardial fibrosis (OR 71, 95% CI = 9-561, p <0.000).
Conclusion: Fragmented QRS independently correlated to myocardial fibrosis by MPI. Since 12 L ECG is cheap, non-invasive and easily apprehensible test, it can be used as an alternative diagnostic test in the prognostication of CAD patients