NuPulse or No Pulse: VT Ablation in A Patient with The NuPulse Ivas Device

Abstract

Introduction The intravascular ventricular assist system (iVAS) is the first minimally invasive, long-term, ambulatory counter-pulsation device that is currently being investigated as a bridge-to-transplant option for patients with advanced heart failure (HF). Ventricular tachycardia (VT) is a common complication in patients with advanced HF. Catheter ablation with substrate modification is an effective management strategy. We describe, to the best of our knowledge, the first reported case of VT ablation in a patient with the NuPulse iVAS device. Case An 82-year-old male came to the ED as his defibrillator discharged 4 times over 48 hours. He had a past history of ACC/AHA Stage D HFrEF (EF of 35%) due to ischemic cardiomyopathy. Given his advanced HF, he was enrolled in the iVAS trial and was implanted in 2019. On arrival, his BP was 172/99 mmHg and HR was 114/min. He was mildly hypervolemic on exam. CXR revealed mild pulmonary vascular congestion (Fig. 1B). ECG showed VT with a rate of 120/min (Fig. 1A). He was given IV procainamide, which transiently converted him to his baseline ventricular-paced rhythm, and his ICD was re-programmed to pace-terminate VT > 102/min. He was then loaded with IV lidocaine. Yet, he continued to have runs of VT. The next day, he underwent an adenosine nuclear stress test which showed a large severe fixed defect in the inferior and inferolateral regions suggestive of scar (Fig 1C). The following day, he underwent a VT ablation. A trans-septal approach was used to enter the LV and the scar was mapped (Fig 1D & E). Interestingly, every time radiofrequency ablation was delivered, there was electromagnetic interference with the iVAS device ECG leads which caused it to turn off. The patient became hypotensive during these episodes and dobutamine was used intra-procedurally for ionotropic support. Ablation was delivered in short bursts to allow the iVAS device to function intermittently, which prolonged the procedure time. The patient tolerated the procedure well and he has not had any recurrent VT. Discussion Long term mechanical circulatory support devices are an exciting emerging field. Complications of advanced HF include VT which is often difficult to control with medication alone and benefits from ablation. However, it appears that electromagnetic interference from radiofrequency ablation delivery impairs function of the iVAS ECG leads which gate the inflation & deflation of the counter-pulsation balloon to the cardiac cycle. Future iterations of the device must consider alternative triggers, such as being able to connect the device's ECG input to surface electrodes which would not be compromised during ablation delivery.