Patients in higher quartiles of QTc interval were tended to be older, and were more likely to have rapid heart rates and a lower proportion of people with a sinus rhythm on baseline ECG, hypertension, and comorbidities, such as AF, CHF, and CKD; and had higher white blood cell (WBC) counts and glucose and possibly C-reactive protein (CRP) concentrations than patients with lower quartiles of QTc interval. Here, CRP is linked to atrial fibrillation.