Biochemical markers in the management of suspected acute myocardial infarction in the emergency department

Effect of a Triage-Based Screening Protocol on Diagnosis and Treatment of Acute Coronary Syndrome in a Tanzanian Emergency Department: A Prospective Pre-Post Study

Background Evidence suggests that acute coronary syndrome (ACS) is underdiagnosed in sub-Saharan Africa. Triage-based interventions have improved ACS diagnosis and management in high-income settings but have not been evaluated in sub-Saharan African emergency departments (EDs). Our objective was to estimate the effect of a triage-based screening protocol on ACS diagnosis and care in a Tanzanian ED. Methods and Results All adults presenting to a Tanzanian ED with chest pain or shortness of breath were prospectively enrolled. Treatments and clinician-documented diagnoses were observed and recorded. In the preintervention phase (August 2018 through January 2019), ACS testing and treatment were dictated by physician discretion, as per usual care. A triage-based protocol was then introduced, and in the postintervention phase (January 2019 through October 2019), research assistants performed ECG and point-of-care troponin I testing on all patients with chest pain or shortness of breath upon ED arrival. Pre-post analyses compared ACS care between phases. Of 1020 total participants (339 preintervention phase, 681 postintervention phase), mean (SD) age was 58.9 (19.4) years. Six (1.8%) preintervention participants were diagnosed with ACS, versus 83 (12.2%) postintervention participants (odds ratio [OR], 7.51; 95% CI, 3.52-19.7; P<0.001). Among all participants, 3 (0.9%) preintervention participants received aspirin, compared with 50 (7.3%) postintervention participants (OR, 8.45; 95% CI, 3.07-36.13; P<0.001). Conclusions Introduction of a triage-based ACS screening protocol in a Tanzanian ED was associated with significant increases in ACS diagnoses and aspirin administration. Additional research is needed to determine the effect of ED-based interventions on ACS care and clinical end points in sub-Saharan Africa.

Acute myocardial infarction under-diagnosis and mortality in a Tanzanian emergency department: A prospective observational study

BACKGROUND

Growing evidence suggests that under-diagnosis of acute myocardial infarction (AMI) may be common in sub-Saharan Africa. Prospective studies of routine AMI screening among patients presenting to emergency departments in sub-Saharan Africa are lacking. Our objective was to determine the prevalence of AMI among patients in a Tanzanian emergency department.

METHODS

In a prospective observational study, consecutive adult patients presenting with chest pain or shortness of breath to a referral hospital emergency department in northern Tanzania were enrolled. Electrocardiogram (ECG) and troponin testing were performed for all participants to diagnose AMI types according to the Fourth Universal Definition. All ECGs were interpreted by two independent physician judges. ECGs suggesting ST-elevation myocardial infarction (STEMI) were further reviewed by additional judges. Mortality was assessed 30 days following enrollment.

RESULTS

Of 681 enrolled participants, 152 (22.3%) had AMI, including 61 STEMIs and 91 non-STEMIS (NSTEMIs). Of AMI patients, 91 (59.9%) were male, mean (SD) age was 61.2 (18.5) years, and mean (SD) duration of symptoms prior to presentation was 6.6 (12.2) days. In the emergency department, 35 (23.0%) AMI patients received aspirin and none received thrombolytics. Of 150 (98.7%) AMI patients completing 30-day follow-up, 65 (43.3%) had died.

CONCLUSIONS

In a northern Tanzanian emergency department, AMI is common, rarely treated with evidence-based therapies, and associated with high mortality. Interventions are needed to improve AMI diagnosis, care, and outcomes.

Case Report: Acute Inferior Myocardial Infarction with Single-Lead ST Segment Elevation

This article illustrates a patient who presented with acute inferior myocardial infarction with only isolated ST segment elevation in Lead III. Brief review on the electrocardiographic interpretation was discussed. Early recognition and management is the key to prevent morbidity and mortality.

Earlier detection of myocardial injury in a preliminary evaluation using a new troponin I assay with improved sensitivity

Cardiac troponins are important biochemical markers for defining the presence of myocardial injury. However, limitations in troponin testing exist, including the relatively late increase in troponin after onset of ischemia. We therefore evaluated a more sensitive troponin assay for detection of myocardial injury in "early presenters." Discarded serial specimens were obtained from 103 patients who had a negative cardiac troponin I (cTnI) result followed by a positive cTnI result. Results were obtained using our current cTnI method and a new more sensitive assay, TnI-Ultra (Siemens Medical Solutions, Diagnostics Division, Tarrytown, NY). Medical records were reviewed to determine the clinical diagnosis. Precision studies yielded a 10% coefficient of variation at the diagnostic cut points for cTnI (0.10 ng/mL [0.10 microg/L]) and TnI-Ultra (0.04 ng/mL [0.04 microg/L]). TnI-Ultra was positive before cTnI in 66 (64.1%) of 103 cases. We conclude that the more sensitive assay, TnI-Ultra, has better analytic performance and has the potential to detect myocardial injury earlier than the current cTnI assay.