New-onset T-wave inversions may predict the diagnosis of non-ST-segment elevation type 1 myocardial infarction over other causes of myocardial injury

Abstract

Background

On presentation, non-ST-segment elevation type 1 myocardial infarction (T1-NSTEMI) can be difficult to distinguish from other causes of myocardial injury (OCMI) such as type 2 myocardial infarction or non-ischemic myocardial injury. New-onset T-wave inversions (NTWI) developed on electrocardiogram (ECG) soon after presentation are considered a sign of post-ischemic changes and may be useful to distinguish T1-NSTEMI from OCMI.

Methods

We assessed all cases of suspected non-ST-segment elevation myocardial infarction seen at the Baylor-St. Luke's Medical Center from 8/2018–7/2019 to determine a final diagnosis of T1-NSTEMI or OCMI. Encounters with ECGs showing T-wave inversions, ST changes, ventricular pacing, or ventricular conduction delay at presentation were excluded, as were those without a follow-up ECG within 24 h. We used adjusted relative risk analysis to assess whether NTWI was associated with T1-NSTEMI.

Results

Of 113 cases included, 33 (29.2 %) developed NTWI and 80 (70.8 %) did not. Twenty-four NTWI cases (72.7 %) and 37 cases without NTWI (46.3 %) were adjudicated as T1-NSTEMIs. The positive and negative likelihood ratios of NTWI for T1-NSTEMI were 2.27 (95 % confidence interval (CI): 1.16, 4.45) and 0.73 (CI: 0.58, 0.93). The unadjusted and adjusted relative risks of T1-NSTEMI for patients with NTWI were 1.57 (CI: 1.15, 2.16, P = 0.005) and 1.69 (CI: 1.22, 2.35, P = 0.002). NTWI had higher specificity (83 %, CI: 70 %, 92 %) for T1-NSTEMI than sensitivity (39 %, CI: 27 %, 53 %).

Conclusion

NTWI is associated with T1-NSTEMI in our study population. NTWI within 24 h on follow up ECG may help distinguish between patients with T1-NSTEMI and OCMI.