Silent myocardial ischaemia: A review of the literature for prehospital care providers

Abstract

Background: There has been little emphasis in paramedic education about silent myocardial ischaemia, its implications, and management in the prehospital environment. There is also inadequate information about the aetiology and prehospital management of silent myocardial infarction. The objective of this study was to review the literature on silent myocardial ischaemia and determine appropriate prehospital management. Methods: A review of the Medline database was conducted from 1950 to the beginning of March 2007. Inclusion criteria were, any study type reporting the epidemiology, pathophysiology, clinical concepts, and management of silent myocardial ischaemia. References of relevant articles were also reviewed. A review of prehospital clinical implications and management was also undertaken. Results: The search yielded 1,332 articles; 110 articles met the inclusion criteria with another 32 articles located from review of relevant articles reference list. Silent myocardial ischaemia is not limited to patients with significant coronary artery disease or cardiovascular risk profiles, it may affect up to 10% of patients with asymptomatic coronary artery disease. Silent myocardial ischaemia is also associated with greater adverse outcomes, and has been defined as the single strongest factor attributing to cardiac death in patients with concurrent angina pectoris. All patients with coronary artery disease presenting with and without pain can be managed with GTN and aspirin, in the absence of contra-indications. Conclusion: This study demonstrates that silent myocardial ischaemia is not limited to patients with significant cardiovascular risk profiles and may affect up to 10% of patients with asymptomatic coronary artery disease. There is little prehospital care providers can achieve with current clinical practice guidelines and management regimes.