Study outcomes
The study primary outcome was any arrhythmia documented during the hospitalization. The search for arrhythmias was based on review of all patients’ medical records, 12-lead ECG’s, 24-hour Holters or continuous ECG monitoring (telemetry).
Our secondary aim was to evaluate possible predictors for arrhythmia occurrence, with regard to:
  1. Patients’ medical history; including age, gender, hypertension (HTN), diabetes mellitus (DM), ischemic heart disease (IHD), background congestive heart failure (CHF), and previous documented arrhythmia
  2. Presenting ”arrhythmic” symptom as palpitations or syncope
  3. Disease severity. Disease severity was categorized primarily according to the patients’ respiratory status, and categorized as mild for those who did not need any O2 support during their hospitalization; moderate for those who required some O2 support via nasal cannula or mask; severe for those who required non-invasive ventilation (high-flow, CPAP, etc); and critical for those who needed mechanical ventilation or alternatively those with multi-organ failure who were supported by inotropes. Notably, disease severity was determined according to the patients’ worst respiratory or hemodynamic status during their hospitalization period.
  4. Presence of cardiac injury as assessed by high-sensitive cardiac troponin-I (hsTnI) and/or Trans Thoracic Echocardiography (TTE).
  5. Inflammatory status based on D-DIMER and CRP lab measurements
  6. QTc duration, as evidenced by review of all patients ECG’s performed during the hospitalization period, determining the ECG with longest QTc duration. Notably, to look for other potential contributors for prolonged QTc we documented the patient’s electrolytes and medications around the day of longest QTc ECG. The QTc was calculated using the Bazett formula. In patients with heart rate of less than 60 QT and not QTc was measured.
  7. COVID-19 treatments, especially regarding use of Hydroxychloroquine and Azithromycin and other QT-prolonging medications