A rare cause of myocardial infarction with non-obstructive coronary arteries-case report of ST-segment elevation myocardial infarction caused by a mediastinal mass

Mechanisms of Myocardial Ischemia in Cancer Patients: A State-of-the-Art Review of Obstructive Versus Non-Obstructive Causes

In patients with cancer, myocardial infarction (MI) has distinct features and mechanisms compared to the non-oncology population. Triggers of myocardial ischemia specific to the oncology population have been increasingly identified. Coronary plaque disruption, coronary vasospasm, coronary microvascular dysfunction, spontaneous coronary artery dissection, and coronary oxygen supply-demand mismatch are all causes of MI that have been shown to have specific triggers related to either the treatments or complications of cancer. MI can occur in the presence or absence of atherosclerotic coronary artery disease (CAD). MI with nonobstructive CAD (MINOCA) is a heterogeneous syndrome that has distinct pathophysiology and different epidemiology from MI with significant CAD (MI-CAD). Recognition and differentiation of MI-CAD and MINOCA is essential in the oncology population, due to unique etiology and impact on diagnosis, management, and overall outcomes. There are currently no reports in the literature concerning MINOCA as a unified syndrome in oncology patients. The purpose of this review is to analyze the literature for studies related to known triggers of myocardial ischemia in cancer patients, with a focus on MINOCA. We propose that certain cancer treatments can induce MINOCA-like states, and further research is warranted to investigate mechanisms that may be unique to certain cancer states and types of treatment.

Infective Endocarditis Causing Acute Myocardial Infarction

Endocarditis is a well-known disease, yet septic embolization resulting in myocardial infarction is much rarer and very infrequently diagnosed in the emergency department (ED). Point-of-Care-Ultrasound (POCUS) can be used to confirm clinical suspicion within minutes of patient presentation, thereby expediting patient care.  We report the case of a 26-year-old female with known intravenous drug use who presented with altered mental status. Her clinical presentation prompted urgent evaluation in the ED with POCUS which showed a hyperdynamic functioning left ventricle, greater than 50% inferior vena cava collapse, and a large tricuspid valve vegetation. In light of the electrocardiogram (ECG) ST changes suggesting an acute myocardial infarction, the patient was emergently taken to the cardiac catheterization laboratory where coronary angiography revealed multiple coronary emboli. Primary diagnoses included endocarditis due to Staphylococcus, septic pulmonary embolism, and ST-elevated myocardial infarction (STEMI) due to embolic occlusion of the distal left anterior descending artery. Myocardial infarction caused by septic embolization from endocarditis is a rare condition; however, POCUS is a quick, non-invasive tool that can aid the emergency medicine (EM) physician in identifying this life-threatening pathology thereby expediting appropriate care for the patient.

STEMI: rare initial presentation of a mediastinal mass supplied by the RCA

In the setting of severe septic shock, a 70-year-old woman had an ST segment myocardial infarction with ST elevations in the inferolateral leads. On cardiac catheterisation, no obstructive pathology was noted. Chest imaging revealed a large mediastinal mass measuring 8.5×6.5×7.5 cm in the visceral compartment of the mediastinum, with contrast enhancement from the right coronary artery (RCA). A biopsy was preformed and cytology was consistent with a well-differentiated neuroendocrine neoplasm. On review of the cardiac catherisation, it was noted that the mass was deriving blood supply from the RCA. Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a rare but well-documented phenomenon. In this case, MINOCA was caused by coronary steal syndrome in the setting of profound hypotension. Immediate management is with haemodynamic support; there is no role for coronary intervention.