Early Left Ventricular Thrombus Following Ventricular Fibrillation/Ventricular Tachycardia Electrical Storm.

UNLABELLED

Left ventricular thrombus (LVT) formation is a serious clinical complication of low-flow states that may be seen in an ischaemic, arrhythmic heart. While LVT formation has a poor prognosis, in the setting of myocardial infarction it is usually a result of post-infarct sequelae such as left ventricle aneurysms, and inflammatory changes from damaged tissue, with the LVT taking several days to form. Arrythmias such as ventricular tachycardia (VT) or ventricular fibrillation (VF) may also lead to thrombus formation, as they contribute to stasis due to decreased cardiac output. Large anterolateral myocardial infarctions can cause electrical or arrhythmic storm, characterized by more than three episodes of VT or VF in a 24-hour period. This prolonged state of dyskinesis further increases the risk of thrombosis, creating a compounding effect. Here, we report the case of a patient who had a VF cardiac arrest with electrical storm secondary to anterolateral myocardial infarction complicated with LVT formation found on echocardiogram after the cardiac arrest, which was absent on presentation. This thrombus formation occurred particularly early during the course of the patient's arrest, possibly due to the compounding factors increasing the risk of thrombosis. Herein, we discuss in detail the risk factors for LVT formation, its mechanism and management options. A review of the literature also shows that LVT formation in the acute phase of arrest, as seen in our patient, is rare.

LEARNING POINTS

Left ventricular thrombus (LVT) formation occurs 3-14 days after myocardial infarction, but in the setting of concomitant ventricular fibrillation arrest, may occur within the first 24 hours.Risk factors for LVT formation include a large infarct, anterior/anterior apical infarction, decreased ejection fraction (particularly <30-35%), left ventricular aneurysm, and delayed time to revascularization.Although diagnosis is generally made on transthoracic echocardiography with intravenous contrast, cardiac MRI with contrast has better sensitivity and specificity.Treatment consists of anticoagulation with a vitamin K antagonist or heparin for 3-6 months with a repeat echocardiogram to confirm the thrombus has organized or resolved. Further trials are needed to assess the efficacy of direct oral anticoagulants.