Association between admission ECG changes and long-term mortality in patients with an incidental myocardial infarction: Results from the KORA myocardial infarction registry.

Background: The aim of this study was to examine the predictive value of specific changes in admission ECG on long-term outcome in acute myocardial infarction (AMI).

Methods: From 2000 until 2017 all AMI cases (n = 9,689) in the study area of Augsburg, Germany, were prospectively recorded. For this study, all patients with a first-time AMI, who survived the first 28 days, were considered. Median observational time was 6.7 years (IQR: 3.6-10.9). Each case was assigned to one of the following groups according to the admission ECG: 'ST-segment elevation', 'ST-segment depression', 'T-wave inversion', 'unspecific changes', 'normal ECG' and 'bundle branch block' (BBB). Multivariable adjusted COX regression models were calculated to compare long-term all-cause mortality.

Results: The final regression model revealed a significantly higher mortality among patients with BBB (HR: 1.52 [1.34-1.73], p-value: < 0.001) and 'ST-segment depression' (HR: 1.16 [1.03-1.29], p-value: 0.01252) compared to the STEMI group (reference group). The 'normal ECG' group (HR: 0.76 [0.66-0.87], p-value: < 0.001) on the other hand was associated with significantly lower long-term mortality. The 'T-wave inversion' group (HR: 1.08 [0.96-1.21]) and the 'unspecific changes' group (HR: 1.05 [0.94-1.17]) did not differ significantly from the STEMI group.

Conclusion: ST-segment depressions and BBB admission ECGs go along with higher long-term mortality in AMI patients compared to STEMI cases. This should be taken into account by physicians when treating patients with NSTEMIs. Only the complete absence of AMI-related ECG changes predicts a more favorable outcome.