Prognostic value of initial QRS analysis in acute anterior myocardial infarction: correlation with left ventricular systolic dysfunction, serum biomarkers, and cardiac outcomes
Authors: Lopez Castillo M , Acena A , Pello-Lazaro A.M , Viegas V , Merchan-Munoz B , Carda R , Franco-Pelaez J.A , Martin-Mariscal M.L , Briongos-Figuero S , Tunon J.A 
Published: November 2020

Abstract

Background
The electrocardiogram (ECG) is an important tool for managing patients with suspected acute myocardial infarction (MI). As it is simple, cost-effective, and fast to use, great effort has been made to study its components for possible use in assessing the prognosis of patients with MI. Our study aim is to evaluate the prognostic value of specific characteristics of QRS complex and pathologic Q waves observed on the ECG of patients with anterior ST elevated myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI).

Methods
We prospectively analyzed the specific characteristics of QRS complex and pathologic Q waves on the first ECG obtained upon presentation to the hospital (admission ECG) and the last ECG before discharge (discharge ECG). We correlated these findings with the development of left ventricular systolic dysfunction (LVSD) 6 to 9 months after the index event, appearance of heart failure (HF) or death during follow-up, and levels of several biomarkers obtained 6 months after the index event.

Results
We included a total of 144 patients with anterior STEMI. Mean age was 61.3±12.5 years and 80% of patients studied were men. Hypertension was present in 48%, and Diabetes mellitus in 19%. Mean left ventricular ejection fraction was 43.83±9.92. On admission ECG mean QRS width was 97.71±19.42 milliseconds and on discharge ECG it was 96.84±18.75. Ninety-one percent of the patients underwent PCI and revascularization was considered to be complete in 79% of the patients. Multivariate logistic regression analysis revealed that on admission ECG, QRS width [OR 1.056 (1.022–1.092) p=0.001] and the sum of Q-wave depth [OR 1.062 (1.022–1.102) p=0.002] were independent predictors of LVSD development. After a median follow up of 2.9±1.5 years, 12 patients (8.4%) developed cardiovascular events, defined as HF or death. Specifically, QRS width on admission ECG, was related to an increased risk of HF or death [HR 1.03, p=0.004]. Regarding biomarkers, QRS width on admission ECG revealed a statistically significant relationship with levels of NT-pro-BNP at 6 months [0.29 (2.95–15.54) p=0.004]. Moreover, the sum of Q-wave depth [0.268 (0.000–0.001) p=0.012] and the sum of Q-wave width [0.247 (0.00–0.00) p=0.021] on admission ECG were related to levels of hs-cTnT at 6 months. The sum of the voltages in precordial leads both on admission ECG [−0.256 (−0.436 to −0.057), p=0.011] and discharge ECG [−0.236 (−0.485 to −0.004), p=0.046] were related to lower levels of PTH at 6 months.

Conclusion
Our study suggests that in patients suffering from anterior STEMI, specific electrocardiographic parameters at baseline and discharge, such as QRS width and pathological Q-wave depth and width, may predict the development of LVSD at 6 months and the rise in several biomarkers associated with increased CV risk. QRS width on the presentation ECG seems to be an early predictor of HF or death after anterior wall STEMI.

Funding Acknowledgement
Type of funding source: None