Abstract P370: Minor Electrocardiographic Abnormalities and Cardiovascular Mortality

Background: Although minor electrocardiographic (ECG) abnormalities are common in clinical practice, their prognostic significance remains unclear due to inconsistent reports. Such inconsistent reports may be related to the focus on the presence vs. absence of minor ECG abnormalities and ignoring the number of abnormalities. Hypothesis: The number of minor abnormalities is associated with cardiovascular disease (CVD) mortality in a dose-response fashion. Methods: This analysis included 6,467 participants (mean age 59 years 53% women, 49% non-Hispanic whites) from the NHANES-III who were free of CVD and major ECG abnormalities. ECG abnormalities were defined from digitally recorded and centrally processed standard 12-lead ECGs using the Minnesota Code ECG Classification. Cause of death was identified using the National Death Index. Cox proportional hazards analysis was used to examine the association between baseline minor ECG abnormalities (presence of at least 1 abnormality vs. normal ECG, and presence of 1, or ≥2 abnormalities vs. normal ECG, separately) with CVD mortality. Results: About 38% (n=2,438) of the participants had at least 1 minor abnormality at baseline. During a median follow-up of 13.9 years, 755 CVD deaths occurred. Compared to normal ECG, presence of minor ECG abnormally was marginally associated with CVD mortality (HR(95%CI):1.16 (1.00, 134); p= .0045). When the number of abnormalities was taken into account, the association with CVD mortality showed a dose-response relationship. While presence of only 1 minor abnormality was not associated with CVD mortality, presence of ≥ 2 abnormalities was associated with a 39% increased risk. Also, each additional minor ECG abnormality was associated a 13% increased risk of CVD mortality ( Table ). Conclusions: The number of minor ECG abnormalities, not only their mere presence, should be taken into account to both understand the prognostic significance of these common findings and to enhance the potential role of ECG to identify individuals at risk for CVD.