To the Editor: Dr Cheng and colleagues1 demonstrated that PR interval prolongation is associated with an increased risk of future AF, need for pacemaker implantation, and all-cause mortality. To help validate this study and determine whether its findings can be incorporated into clinical practice, it would be helpful to have a number of pieces of information about associated conditions that could have contributed to PR prolongation and its outcomes.
Doraiswamy VA. Outcomes in Patients With Prolonged PR Interval or First-Degree Atrioventricular Block. JAMA. 2009;302(18):1967-1968. doi:10.1001/jama.2009.1604