Clinical Use of High-sensitivity Cardiac Troponin in Patients With Suspected Myocardial Infarction

Raphael Twerenbold, MD; Jasper Boeddinghaus, MD; Thomas Nestelberger, MD; Karin Wildi, MD; Maria Rubini Gimenez, MD; Patrick Badertscher, MD; Christian Mueller, MD

Disclosures

J Am Coll Cardiol. 2017;70(8):996-1012. 

In This Article

hs-cTn in Patients With Left Bundle Branch Block

Patients with suspected MI and left bundle branch block (LBBB) present a unique diagnostic and therapeutic challenge for clinicians in the ED. It is currently unknown whether patients presenting with acute chest pain and presumably new LBBB should also receive immediate coronary angiography and/or thrombolysis therapy such as those with clear STEMI. This major uncertainty is highlighted by divergent recommendations given by the respective guidelines in the United States and Europe.[98,99] In recent years, most patients presenting with suspected MI and LBBB have been found to have diagnoses other than MI, probably based on the more accurate classification of MI in the primary PCI era.[100] The distribution of new or presumably new versus known LBBB has changed over the years. Although chronic LBBB has become more common, incident LBBB in MI has decreased.[101] Several studies have demonstrated no difference in the prevalence of MI between patients with presumably new or known LBBB, suggesting that true MI related LBBB is indeed rare.[102,103]

Due to their high specificity, specific ECG criteria including Sgarbossa, Smith, and Selvester criteria should be used to triage patients toward rule-in of MI and immediate coronary angiography such as patients with STEMI.[104,105] Despite the present evidence supporting the use of these ECG criteria in new or indeterminate-age LBBB, it must be stated that current guidelines do not specifically include this application of the criteria in their recommendations. Patients not meeting these ECG criteria have only a slightly higher overall prevalence of MI as compared with patients without LBBB and should undergo standard serial testing for hs-cTn.[102,103]

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