(232) Double Jeopardy: A Case of Dual Tachycardia

Introduction: Dual tachycardia is the coexistence of two distinct tachyarrhythmias simultaneously or in an alternating manner. Proposed mechanisms include increased sympathetic activation of the heart by an atrial arrhythmia leading to ventricular tachycardia. Due to the challenges associated with the diagnosis and management of this phenomenon, there has been growing interest in this rare occurrence. Herein, we present a case of dual tachycardia.

Description: A 64-year-old female with a history of systolic heart failure status-post CRT-D placement was admitted with acute heart failure decompensation complicated by cardiogenic shock. Vitals at the ED showed a heart rate of 154 bpm, SPO2 of 88% on room air, and blood pressure of 82/55 mmHg. The lab was significant for creatinine of 1.9 mg and lactate of 5.1 mmol/L. A chest radiograph showed pulmonary congestion. EKG showed atrial fibrillation (AFib) with rapid ventricular response (RVR). Echocardiography revealed a left ventricular ejection fraction of 15-20%. Cardiology was consulted and she was emergently cardioverted. She, however, went back into AFib in less than 30 minutes which was thought to be due to hypervolemia, and was started on IV furosemide 80 mg, an amiodarone drip for rate/rhythm control, and milrinone for positive inotropy since it is less arrhythmogenic. The hospital course was complicated by recurrent sustained ventricular tachycardia (VT) which was defibrillated but her AFib persisted after each defibrillation until she was successfully cardioverted into a biventricular paced rhythm. Unfortunately, she could not come off the milrinone with declining mixed venous oxygen saturation on each attempt. Advanced device therapies were discussed, but she declined further treatment and went home on hospice with a milrinone infusion.

Discussion: Dual tachycardia should be suspected in cases of recalcitrant tachyarrhythmia despite the absence of electrolyte abnormalities and other arrhythmogenic triggers. Based on expert opinion, the termination of the inducing rhythm prevents the recurrence of the VT. Our case demonstrated that although rare and associated with adverse cardiovascular outcomes, early identification of dual tachyarrhythmia and termination of the inducing arrhythmia leads to a favorable outcome.