Electrocardiographic T-wave morphology and risk of mortality

Background
Electrocardiographic T-wave morphology is used in drug safety studies as an adjunct to the QT c interval, but few measurements of T-wave morphology can be interpreted in clinical practice. Morphology combination score (MCS) is a combination of T-wave flatness/peakedness, asymmetry, and notching, enabling easy visual assessment of T-wave morphology. We aimed to test the association between T-wave morphology, quantified by MCS, and mortality.
Methods
We included electrocardiograms recorded in 2001–2011 from 342,294 primary care patients. Using Cox regression, we evaluated the association between MCS, cardiovascular death, and all-cause mortality, adjusting for heart rate, QT c, QT-prolonging drugs, diabetes, ischemic heart disease, hypertension, and congestive heart failure.
Results
270,039 individuals (44% men, median age 55 [inter-quartile range: 42–67 years]) were included and followed for a median of 9.3 years, during which time 13,489 (5.0%) died from cardiovascular causes and 50,481 (18.7%) from any cause. High values of MCS (i.e. asymmetric, flattened, and/or notched T waves) were associated with an adjusted mortality Hazard Ratio of 1.75 (95% CI 1.62–1.89) and 1.61 (1.43–1.92) for women and men, respectively. Low values of MCS (i.e. peaked and symmetric T waves) were associated with a Hazard Ratio of 1.18 (1.08–1.28) and 1.71 (1.48–1.98) for women and men, respectively.
Conclusions
In a large primary care population, we found that T-wave asymmetry, flatness, and notching provided prognostic information on mortality independent of heart rate, QTc, and baseline comorbidities.