Cardiac resynchronization therapy in treatment of a non-ischemic cardiomyopathy patient with massive left ventricular thrombus

Rationale: Left ventricular thrombosis is a severe and potentially fatal complication of cardiomyopathies with reduced ejection fraction. The mainstay of treatment is anticoagulation, with variable response to thrombus resolution. In patients with reduced ejection fraction and left bundle branch block, cardiac electrical resynchronization is established as a very effective therapy, leading to improvement in left ventricular function. Patient concerns: We present the case of a 64-year-old male with non-ischemic cardiomyopathy with severely reduced ejection fraction and left bundle branch block, who was implanted with a dual-chamber pacemaker in 2018 for sick sinus node disease and who was admitted for progressive shortness of breath. Diagnosis: Echocardiography showed a dilated left ventricle with a severely reduced ejection fraction (15%) and a massive left intraventricular thrombus. Interventions: The patient was started on anticoagulant and heart failure therapy without any response in thrombus size, so as a last resort measure, cardiac resynchronization therapy was added. Outcomes: The 6-month echocardiography follow-up showed a significant improvement in left ventricular function and complete thrombus resolution. Lesson: Cardiac resynchronization therapy promotes reverse remodeling and improves the contraction sequence in the left ventricle, thus eliminating the triggers for thrombosis and aiding in thrombus resolution.