C80-39 An Unfortunate Road Block: Obstructive Ventricular Tachycardia Secondary to an Invasive Mediastinal Mass

Abstract Introduction Right ventricular outflow tract obstruction (RVOT) is a potential etiology for cardiac ectopy and even ventricular tachycardia (VT). Malignant obstruction of the outflow tract via direct tumor invasion or mass effect is uncommon but can beget refractory arrhythmias and carries an overall poor prognosis. Description of Case A 67-year-old female with history of COPD and hypothyroidism presented to an outside hospital for complaints of cough and intermittent hemoptysis for the preceding two months. She denied fevers and chills, however, reported unintentional weight loss over the same duration. Patient did not use home oxygen at baseline, but she required high flow nasal cannula at 30 L/min and 40% FiO2 to maintain appropriate saturations while in the emergency department. CT angiogram of the chest revealed a moderate-to-large L pleural effusion and a 13 x 9.5 cm mediastinal mass with mild-to-moderate compression of the L main pulmonary artery secondary to mass effect. At this time, patient was transferred to our facility for escalation of care. Thoracentesis of the pleural fluid yielded 1,100 mL of serosanguinous fluid, and cytology of this fluid revealed grade 3 small cell carcinoma. Biopsy of the mass during bronchoscopy with endobronchial ultrasound guidance yielded the same pathology. Patient was tolerating the post-procedure period well until she began developing intermittent runs of non-sustained VT as seen on telemetry, during which her only complaint was of palpitations. Cardiac electrophysiology was consulted and started metoprolol tartrate. While this limited runs of VT, the patient was still noted to have frequent bigeminal premature ventricular contractions (PVCs) which made her feel short of breath and fatigued. In response, flecainide was added to her regimen and titrated to provide adequate suppression. She was discharged with a cardiac monitor and plans to follow up outpatient. Shortly following discharge, patient uncharacteristically missed several of her appointments and a wellness check was called. She was found unresponsive at home in asystole per emergency medical services and was pronounced shortly thereafter. Discussion While the management of VT is well described for a variety of clinical contexts, there is a paucity of data relating to the appropriate treatment of VT secondary to RVOT. In patients such as the one described in this case, prompt removal of the arterial obstruction is not feasible and optimal medical management of her arrhythmia was unclear. Overall, compression of the great vessels from tumor mass effect carries a poor prognosis. This abstract is funded by: None