Yang T, Fu X, Fu P, et al. - Researchers examined the association between fragmented QRS (fQRS) and coronary collateral circulation (CCC) as well as assessed the predictive worth of fQRS for long‐term clinical results in patients having chronic total occlusion (CTO) and prior myocardial infarction (MI) who received percutaneous coronary intervention (PCI). They continuously examined 862 patients with a definite history of MI who had one CTO coronary artery and received PCI between 2013 and 2018. Participants were split into group A (no Q wave and fQRS, n = 206), group B (fQRS, n = 265), group C (Q wave, n = 391). An observation for 2 years was conducted in all patients. Group B vs group C had a significantly lower incidence rate of major adverse cardiovascular events (MACE). In patients with prior MI and one CTO vessel who had PCI, fQRS was identified as an independent protective factor of prognosis, presenting with a higher rate of good CCC, less occurrence of MACE, and better heart function vs Q wave patients.