Related Experiment Video
Updated: Sep 21, 2025

Cutoff Value of Phase Angle by Bioelectrical Impedance Analysis at Admission as a Prognostic Factor in Patients with Acute Heart Failure
Published on: June 10, 2025
Frontal QRS/T angle can predict mortality in COVID-19 patients
Ramazan Gunduz1, Bekir Serhat Yildiz2, Su Ozgur3
1Department of Cardiology, Manisa City Hospital, Manisa, Turkey.
Aims:
The frontal QRS-T (fQRS) angle has been investigated in the general population, including healthy people and patients with heart failure. The fQRS angle can predict mortality due to myocarditis, ischaemic and non-ischaemic cardiomyopathies, idiopathic dilated cardiomyopathy, and chronic heart failure in the general population. Moreover, no studies to date have investigated fQRS angle in coronavirus disease 2019 (COVID-19) patients. Thus, the purpose of this retrospective multicentre study was to evaluate the fQRS angle of COVID-19 patients to predict in-hospital mortality and the need for mechanical ventilation.
Methods And Results:
An electrocardiogram was performed for 327 COVID-19 patients during admission, and the fQRS angle was calculated. Mechanical ventilation was needed in 119 patients; of them, 110 died in the hospital. The patients were divided into two groups according to an fQRs angle >90° versus an fQRS angle ≤90°. The percentages of mortality and the need for mechanical ventilation according to fQRS angle were 67.8% and 66.1%, respectively, in the fQRs >90° group and 26.1% and 29.9% in the fQRS ≤90°group. Heart rate, oxygen saturation, fQRS angle, estimated glomerular filtration rate, and C-reactive protein level were predictors of mortality on the multivariable analysis. The mortality risk increased 2.9-fold on the univariate analysis and 1.6-fold on the multivariate analysis for the fQRS >90° patient group versus the fQRS ≤90° group.
Conclusion:
In conclusion, a wide fQRS angle >90° was a predictor of in-hospital mortality and associated with the need for mechanical ventilation among COVID-19 patients.
More Related Videos
Related Concept Videos
Acute Coronary Syndrome III: Diagnostic Studies
Electrocardiogram
Three major waveforms are present in a typical ECG recording: the P wave, the QRS complex, and...
Acute Coronary Syndrome I: Introduction
Dysrhythmias IV: Characteristics of Bradyarrhythmias
ECG Interpretation of Arrhythmias I: Sinus Arrhythmias
Types of Arrhythmias
Sinus Node Arrhythmias
Sinus Bradycardia: Originating from the sinoatrial (SA) node, sinus bradycardia involves slower impulses, resulting in a heart rate of less than 60 beats per minute (bpm). Causes include sleep, vagal stimulation, beta-blockers, hypothyroidism,...
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias

