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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.
Insights
A wide frontal QRS-T (fQRS) angle (>90°) in COVID-19 patients predicts in-hospital mortality and the need for mechanical ventilation. This finding highlights the fQRS angle as a crucial prognostic indicator in coronavirus disease 2019 patients.
Area of Science:
- Cardiology
- Critical Care Medicine
- Infectious Diseases
Background:
- The frontal QRS-T (fQRS) angle is a known predictor of mortality in various cardiac conditions.
- No prior studies have investigated the prognostic value of the fQRS angle in coronavirus disease 2019 (COVID-19) patients.
Purpose of the Study:
- To evaluate the frontal QRS-T angle in COVID-19 patients.
- To determine if the fQRS angle can predict in-hospital mortality.
- To assess the association between the fQRS angle and the need for mechanical ventilation in COVID-19 patients.
Main Methods:
- Retrospective, multicenter study involving 327 COVID-19 patients.
- Electrocardiogram performed on admission to calculate the fQRS angle.
- Patients categorized into two groups: fQRS angle >90° and fQRS angle ≤90°.
Main Results:
- A significantly higher percentage of mortality (67.8%) and mechanical ventilation (66.1%) was observed in the fQRS >90° group compared to the fQRS ≤90° group (26.1% mortality, 29.9% ventilation).
- Multivariable analysis identified heart rate, oxygen saturation, fQRS angle, estimated glomerular filtration rate, and C-reactive protein level as predictors of mortality.
- Patients with an fQRS angle >90° had a 1.6-fold increased risk of mortality (multivariate analysis).
Conclusions:
- A wide frontal QRS-T angle (>90°) is a significant predictor of in-hospital mortality in COVID-19 patients.
- An elevated fQRS angle is associated with an increased likelihood of requiring mechanical ventilation among COVID-19 patients.
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.
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