Relationship between ECG QRS voltage and left ventricular functions in patients with heart failure attending federal Medical Centre Nguru, Northeastern Nigeria

Abstract

Introduction: Heart failure (HF) is a clinical syndrome characterized by typical symptoms (e.g., breathlessness, ankle swelling, and fatigue) that may be accompanied by signs (e.g. elevated jugular venous pressure, pulmonary crackles, and peripheral edema) caused by a structural and/or functional cardiac abnormality, resulting in a reduced cardiac output and/or elevated intracardiac pressures at rest or during stress. Electrocardiogram (ECG) is a widely available tool; it is relatively inexpensive and simple to perform; and it yields an instant result. A normal ECG makes systolic dysfunction unlikely and is rare in patients with suspected heart failure. Low ECG voltage has been reported as a marker of the severity of HF and is a risk factor for adverse outcomes in patients with systolic HF at 1 year. However, the relationship between ECG QRS voltage and left ventricular function in patients with heart failure has not been evaluated. Therefore, the objective of this study is to determine the relationship between electrocardiographic QRS voltage and left ventricular function. Methodology: This was a prospective cross-sectional study conducted among inpatients with HF in the medical ward of the hospital. Results: Three hundred and sixty patients were recruited for the study, of which 19 had incomplete data and were excluded in the analysis. The remaining 341 subjects were analyzed comprising 215 female and 126 male with a mean age of 47.54 ± 18.85 years. Majority of patients with normal or high QRS voltage had HF with preserved ejection fraction (HFpEF), while those with low QRS voltage had HF with reduced ejection fraction (HFrEF). On the other hand, patients with high QRS voltage had impaired relaxation pattern of diastolic dysfunction, while those with low QRS voltage had a restrictive pattern of diastolic dysfunction. There was a positive and significant correlation between the QRS voltage and ejection fraction, fractional shortening, isovolumic left ventricular relaxation time, and left ventricular deceleration time, while a negative but not significant correlation was observed between electrocardiographic QRS voltage and transmitral E/A ratio. Majority of patients with normal QRS voltage had normal left ventricular geometry, while those with high QRS voltage predominantly had concentric left ventricular hypertrophy and those with low QRS voltage had eccentric left ventricular hypertrophy. Patients with concentric left ventricular hypertrophy had predominantly HFpEF and impaired relaxation pattern of diastolic dysfunction, while those with eccentric left ventricular hypertrophy had HFrEF and restrictive pattern of diastolic dysfunction. Conclusion: HF patients with high QRS voltage had preserved left ventricular systolic function, impaired relaxation pattern of left ventricular diastolic dysfunction, and concentric left ventricular hypertrophy. While those with low QRS voltage predominantly had reduced left ventricular systolic function, restrictive pattern of left ventricular diastolic dysfunction, and eccentric left ventricular hypertrophy.