Digital ECG detection of flat T waves predicts cardiovascular events in high-risk patients: the Coupling Study

The prognostic significance of flat T-wave findings remains unclear. This study investigated the association between flat T-wave patterns and cardiovascular events. We analyzed data from 4508 patients with cardiovascular risk who were enrolled in the multicenter, prospective Coupling Study, with available electrocardiographic (ECG) records and follow-up outcomes (mean age 69 years; 51% male). Flat T waves were defined as T waves with an amplitude <0.1 mV and a T wave-to-R wave ratio of <10% in ≥2 of leads I, II, aVL, and V4-V6. Negative ST-T findings were defined as the area below the baseline in the ST-T segment. The primary endpoint was cardiovascular events, including stroke, myocardial infarction, hospitalization for heart failure, and aortic dissection. Over a median 5.0-year follow-up, 210 cardiovascular events occurred. Compared to the control group (N = 3426), both the flat T-wave (N = 539) and negative ST-T (N = 541) groups exhibited significantly greater risk of cardiovascular events after adjustment for age, gender, smoking, comorbidities, medications, office systolic blood pressure, N-terminal pro-B-type natriuretic peptide, and troponin T (flat T: hazard ratio [HR] 1.52, 95% confidence interval [CI], 1.01-2.29; p = 0.044; negative ST-T: HR 2.23, 95% CI, 1.58-3.15; p < 0.001). Findings in patients with hypertension (N = 4135) were consistent with those in the overall cohort: the flat T group had an HR of 1.54 (95% CI, 1.03-2.33; p = 0.037), and the negative ST-T group had an HR of 2.24 (95% CI, 1.57-3.18; p < 0.001) for incidence of cardiovascular events. In conclusion, flat T-wave findings on ECG were independently associated with cardiovascular events among patients with cardiovascular risk, including those with hypertension.