QTc Prolongation to Predict Mortality in Patients Admitted with COVID-19 Infection: An Observational Study

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes Coronavirus disease 2019 (COVID-19), characterized by pulmonary infection ranging from asymptomatic forms to respiratory insufficiency and death. Evidence of cardiac involvement in COVID-19 is increasing, and systemic inflammation or direct heart damage by SARS-CoV-2 can prolong the corrected QT interval (QTc).

In this observational study, a total of 333 consecutive patients admitted to the Covid Center of Verona University Hospital from November 2020 to April 2021 were included. Patients with bundle branch block, pacemaker-controlled heart rhythm and heart rate >120 beats/min were excluded. A complete electrocardiogram (ECG) was performed at admission, and QTc values of ≥440 ms for males and ≥460 ms for females were considered prolonged.

Overall, 153 patients had prolonged QTc (45.5%). In multivariate logistic regression analysis, male sex (odds ratio (OR)=6.612, p=0.046), troponin (OR=1.04, p=0.015) and lymphocyte count (OR=3.047, p=0.019) were independently associated with QTc prolongation. Multivariate logistic regression showed that QTc was independently associated with mortality (OR=4.598, p=0.036). Age, sex, the ratio between the partial pressure of oxygen (PaO2) and the fraction of inspired oxygen (FiO2) (P/F), and fibrosis-4 index for liver fibrosis (FIB-4) were also independently associated with mortality.

QTc interval prolongation appears to be a frequent finding in patients with COVID-19. Moreover, prolonged QTc may be predictive of more severe forms of COVID-19 and worse outcome.