Accuracy of OMI ECG findings versus STEMI criteria for diagnosis of acute coronary occlusion myocardial infarction

Abstract

Objective: In the STEMI paradigm of Acute Myocardial Infarction (AMI), many NSTEMI patients have unrecognized acute coronary occlusion MI (OMI), may not receive emergent reperfusion, and have higher mortality than NSTEMI patients without occlusion. We have proposed a new OMI vs. Non-Occlusion MI (NOMI) paradigm shift. We sought to compare the diagnostic accuracy of OMI ECG findings vs. formal STEMI criteria for the diagnosis of OMI. We hypothesized that blinded interpretation for predefined OMI ECG findings would be more accurate than STEMI criteria for the diagnosis of OMI.

Methods: We performed a retrospective case-control study of patients with suspected acute coronary syndrome. The primary definition of OMI was either 1) acute TIMI 0-2 flow culprit or 2) TIMI 3 flow culprit with peak troponin T $\ge$ 1.0 ng/mL or I $\ge$ 10.0 ng/mL.

Results: 808 patients were included, of whom 49% had AMI (33% OMI; 16% NOMI). Sensitivity, specificity, and accuracy of STEMI criteria vs Interpreter 1 using OMI ECG findings among 808 patients were 41% vs 86%, 94% vs 91%, and 77% vs 89%, and for Interpreter 2 among 250 patients were 36% vs 80%, 91% vs 92%, and 76% vs 89%. STEMI(-) OMI patients had similar infarct size and mortality as STEMI(+) OMI patients, but greater delays to angiography.

Conclusions: Blinded interpretation using predefined OMI ECG findings was superior to STEMI criteria for the ECG diagnosis of Occlusion MI. These data support further investigation into the OMI vs. NOMI paradigm and suggest that STEMI(-) OMI patients could be identified rapidly and noninvasively for emergent reperfusion using more accurate ECG interpretation.

Keywords: ACS, Acute coronary syndrome; AMI, acute myocardial infarction; Acute coronary syndromes; ECG, Electrocardiogram; ED, Emergency department; Electrocardiography; LBBB, Left Bundle Branch Block; MIRO, Myocardial Infarction Ruled Out; MSC, Modified Sgarbossa Criteria; NOMI, Non-occlusion myocardial infarction; NSTEMI, Non-ST-segment elevation myocardial infarction; OMI, Occlusion myocardial infarction; Occlusion myocardial infarction; ST elevation myocardial infarction; STD, ST-segment depression; STE, ST-segment elevation; STEMI, ST-segment elevation myocardial infarction; VPR, Ventricular Paced Rhythm.

Fig. 1

The ACS spectrum using the Occlusion MI (OMI) vs. Non-OMI (NOMI) paradigm primarily. The proposed paradigm of MI divides AMI into OMI and NOMI. OMI are those for whom thrombolytics and percutaneous coronary intervention were conceptually designed and indicated, but many OMI do not manifest STEMI criteria. ACS, acute coronary syndrome, MI, myocardial infarction, STEMI, ST-segment elevation MI, OMI, Occlusion MI, NOMI, Non-Occlusion MI.

Fig. 2

This patient was found to have OMI of the mid-RCA (pre-intervention TIMI 1 flow, 99% stenosis with thrombus), correctly diagnosed on the first ECG by the OMI criteria but missed by STEMI criteria despite 5 ECGs prior to angiogram, with a delay of 21.4 h (cath performed next day due to “NSTEMI”). Although it is not subtle, the ECG does not meet STEMI criteria because only one lead (III) has 1 mm STE, without 1 mm in adjacent leads (II and aVF). The documentation states: “…substernal chest pain and pressure which radiated to the jaw area and found to have ruled in for a NSTEMI via positive cTns. Referred for cardiac catheterization.” This presentation ECG shows all 7 of the above findings (top panel without annotation, bottom panel with). This patient had a very high peak cTnT of 3.74 ng/mL, a new inferoposterior wall motion abnormality, and a newly depressed EF of 40%, but survived to discharge.

Fig. 3

Top panel: This 37 year-old male was found to have an acute thrombotic 90% lesion in the proximal LAD with TIMI 3 flow at the time of cath. cTnI rose from undetectable to 5.80 ng/mL within three hours with no further serial cTns measured. Bottom Panel: This 46 year-old male was found to have an acute thrombotic 90% lesion in the mid-LAD with TIMI 3 flow at the time of cath; cTnI peaked at 4.44 ng/mL. Both interpreters diagnosed both patients as OMI of the LAD using only the ECG and age (no other history provided). Both cases were counted as “false positives” because the TIMI flow of the lesions and the peak recorded cTns were insufficient according to our primary outcome definition. Neither case had any ECG (out of 7 total) meeting STEMI criteria (bottom panel measurements at J-point, relative to QRS onset per 4th Universal Definition of MI: V1 0 mm, V2 1.2 mm, V3 1.6 mm, V4 1.1 mm, V5 0.8 mm V6 0.7 mm). In both cases, serial ECGs evolved in confirmation of abnormal subtle STE.

Fig. 4

Graph showing peak cTnT by MI category for SBUH patients. From left to right, the initial group of all patients is divided into STEMI(+) and STEMI(−) based on ECG criteria, as per the current paradigm. Next, the STEMI(−) group is further divided based on the presence of OMI criteria, showing the result of the OMI paradigm. The STEMI(−) OMI criteria(+) category shows the subset of patients with large infarcts due to OMI which are missed by the STEMI paradigm but diagnosed by the proposed OMI criteria.