Study design and patient selection
This retrospective study was approved by the Quality Improvement Assessment Board (QIAB) at MD Anderson Cancer Center. We initially identified all 12-lead ECGs performed between November 23rd, 2019 and January 31st, 2020. Based on the available ECGs, we included inpatients with a newly signed or verified order for a QTc-prolonging medication, and at least two 12-lead ECG readings: A baseline ECG in sinus rhythm within three days before the QTc-prolonging medication was signed or verified, and a follow-up ECG any time after, up to a maximum of eleven days (i.e., within a fourteen-day time period from the baseline ECG reading). We excluded patients with a pacemaker or with a QRS complex greater than 120 ms. We targeted a sample size of 100 patients and discontinued our ECG screening when we reached this goal.