Abstract 4347178: Late Presentation Myocardial Infarction With Dueling Mechanical Complications: Dynamic Left Ventricular Outflow Tract Obstruction (LVOTO) and Ventricular Septal Rupture (VSR)

Introduction: Post-myocardial infarction ventricular septal defect (MI-VSD) is a rare, often fatal complication of MI, regardless of treatment approach. Presentations vary from new murmurs to acute cardiogenic shock. This case describes a patient with delayed MI presentation complicated by ventricular rupture. Case Presentation: An 81-year-old woman with B-cell lymphoma, emphysema, and autoimmune hepatitis presented with progressive dyspnea and cough. Initially treated for an upper respiratory infection, she deteriorated and arrived in SCAI C cardiogenic shock. She was hypoxemic on high-flow nasal cannula; blood gas showed severe acidosis and lactate of 13.9 mmol/L. Exam revealed bibasilar rales, cool mottled extremities, and no murmur. ECG showed tachycardia with new anterolateral Q waves and ST elevation in V2–V5, prompting STEMI activation. Bedside echo showed apical and inferoseptal akinesis. Coronary angiography was deferred due to delayed presentation and down-trending high-sensitivity troponin (618 ng/L). She was admitted to the CCU, where shock improved with norepinephrine, milrinone, and IV diuresis. Her course was complicated by new-onset atrial fibrillation with RVR. Despite IV amiodarone, RVR persisted, along with worsening respiratory status and increasing vasopressors needs. Limited echocardiography revealed basal hypercontractility and dynamic LV outflow tract obstruction (LVOTO). Esmolol was considered to reduce the gradient. Simultaneously, pulmonary artery catheter readings suggested new left-to-right shunting. A new loud holosystolic murmur was heard, and repeat echocardiogram confirmed a large ventricular septal rupture (VSR). Per the patient’s prior wishes, surgical intervention was deferred. Palliative care was initiated, and the patient passed away comfortably. Discussion: This case underscores the importance of vigilance for both arrhythmogenic and mechanical complications in late-presenting, un-revascularized MI. The presence of dual complications—dynamic LVOTO and VSR—illustrates the clinical complexity. This case also highlights key decision points regarding temporary mechanical circulatory support and the need to weigh aggressive interventions against patient goals in frail, multi-morbid individuals, where benefit to quality of life and survival may be limited.