Point-of-care ultrasound may expedite diagnosis and revascularization of occult occlusive myocardial infarction

Abstract

Background: Electrocardiographically occult occlusive myocardial infarction (OOMI), defined as coronary artery occlusion requiring revascularization without ST-segment elevation on electrocardiogram (ECG), is associated with delayed diagnosis resulting in higher morbidity. Left ventricular (LV) wall motion abnormalities (WMA) appreciated on echocardiography can expedite OOMI diagnosis. We sought to determine whether point-of-care ultrasound (PoCUS) demonstrating WMA expedites revascularization time when performed on emergency department patients being evaluated for OOMI.

Methods: This was a single-site retrospective cohort study over a 38-month period. All admitted adult ED patients ≥35 years of age evaluated by the emergency physician with PoCUS for LV function, an ECG, and a standard troponin I biomarker assay were included. Patients with ST-segment elevation myocardial infarction (STEMI), prior LV dysfunction, fever ≥100.4 °F, or hypotension were excluded. A structured chart abstraction was performed for relevant demographic and clinical characteristics.

Results: We screened 1561 ED patients who underwent cardiac PoCUS for eligibility: 874 met exclusion criteria, 453 were discharged, and 234 were included in the analysis. Twenty-three patients had coronary interventions, of which 14 had WMA. PoCUS was performed 36 min (IQR -9-68) before troponin resulted (n = 234) and 39 min (IQR -23-96) before the first troponin elevation (n = 85). Twenty of the 23 patients diagnosed with OOMI had elevated troponins prior to catheterization with time from PoCUS to first troponin elevation of 43 min (IQR 9-263). Of these patients, 11 had WMA identified on PoCUS, and the WMA was appreciated 47 min (IQR 26-255) prior to troponin elevation. The time from ED arrival to revascularization was 673 min (IQR 251-2158); 432 min (IQR 209-1300) among patients with WMA (n = 14) compared with 2158 min (IQR 552-3390) for those without WMA (n = 9).

Conclusion: Cardiac PoCUS may identify OOMI earlier than standard evaluation and may expedite definitive management.

Keywords: Occlusive myocardial infarction; Point-of-care ultrasound; Wall motion abnormality.