Risk factors and electrocardiographic predictors associated with new-onset atrial fibrillation in hospitalized COVID-19 patients. Evaluation of a novel P-wave index

Background New-onset atrial fibrillation (AF) during hospitalization for COVID-19 is linked to prolonged stay and higher in-hospital mortality; early risk stratification may enable targeted monitoring and intervention. Purpose To identify clinical and electrocardiographic (ECG) predictors of new-onset AF in adults hospitalized for COVID-19 and to evaluate a novel P-wave index (Peq-time: time from P-wave onset to peak positive deflection in V1). Methods Pre-specified sub-study of an international cohort of adults hospitalized with PCR-confirmed COVID-19 who had a digitally stored 12-lead ECG at admission1. Patients with prior AF were excluded. Admission demographics, clinical variables and automated ECG measures were analyzed. New-onset AF (at admission or during hospital stay) was the primary outcome; in-hospital clinical outcomes included all-cause mortality and major adverse cardiovascular events (MACE). Multivariable logistic regression and ROC analysis determined independent predictors and optimal cut-offs; four predictive models were internally validated with bootstrapping. Results The sub-study included 921 patients (mean age 60.9 ±16.2 years; 38.8% women). New-onset AF occurred in 59 (6.4%). Independent electrocardiographic predictors of new-onset AF were Peq-time >33 ms (OR 2.81; 95% CI 1.53–5.17), PR-interval >190 ms (OR 4.33; 95% CI 1.98–9.47) and P-wave duration >115 ms (OR 1.99; 95% CI 1.15–3.46). Independent clinical predictors of new-onset AF included initial ICU admission (OR 7.67; 95% CI 4.09–14.42), need for respiratory support (OR 4.14; 95% CI 2.33–7.38), increasing age, male sex and higher BMI. Logistic regression predictive models that included age, sex, BMI, referral to ICU and one of the three electrocardiographic predictors yielded very good balanced accuracies; 79.7% for Peq-time>33ms, 79.4% for PR-interval>190ms and 76.8% for PWD>115ms. New-onset AF was strongly associated with poor clinical outcomes: all-cause mortality was 40.7% in patients with new-onset AF versus 13.0% without (OR 3.31; 95% CI 1.79–6.13; p<0.001), MACE occurred in 40.7% of new-onset AF patients versus 14.0% without (driven mainly by heart failure 27.1% vs 3.7% and thromboembolism 18.6% vs 9.4%). Patients with new-onset AF had significantly longer ICU and overall COVID-19 unit length of stay. Conclusion In hospitalized COVID-19 patients, the novel Peq-time >33 ms, PR-interval >190 ms and P-wave duration >115 ms independently predict new-onset AF. Predictive models that combine routine clinical data with automated ECG indices (Peq-time or PR-interval) yielded the best prediction of new-onset AF. Risk stratification may support early monitoring strategies to mitigate adverse outcomes.