Ramirez AH, Schildcrout JS, Blakemore DL, Masys DR, Pulley JM, Basford MA, Roden DM, Denny JC. Modulators of normal electrocardiographic intervals identified in a large electronic medical record. Heart rhythm : the official journal of the Heart Rhythm Society. 2011 Feb;8(8). 271-7. PMID: 21044898 [PubMed] PMCID: PMC3057498 NIHMSID: NIHMS249803.
Traditional electrocardiographic (ECG) reference ranges were derived from studies in communities or clinical trial populations. The distribution of ECG parameters in a large population presenting to a healthcare system has not been studied.