B-PO01-004 NOCTURNAL VENTRICULAR TACHYCARDIA STORM: A MAN-MADE PHENOMENON

Abstract

Drug refractory, rapid AF can be treated by atrioventricular junction (AVJ) catheter ablation with use of an existing or coincident pacemaker. Increased risk of sudden cardiac death (SCD) related to VF or polymorphic VT (PMVT) has been described afterwards. This is likely secondary to increased dispersion of ventricular refractoriness & is bradycardia-dependent. Malignant ventricular arrhythmias are reduced by increasing the basal pacing rate for several weeks after ablation. We report a case of nocturnal PMVT storm due to the Sleep Rate feature in an ICD being inadvertently left on following AVJ ablation. N/A A 68-year-old male with a history of NICM, primary prevention biventricular ICD (2018), permanent AF, HTN, COPD, chronic kidney disease, acute COVID-19 infection, and recent AVJ ablation 2 weeks prior, presented with VT storm & 21 ICD shocks. No prior significant burden of VT or NSVT was noted. A device interrogation showed normal function and programming (VVIR 90). He was started on IV amiodarone for arrhythmia suppression, however, continued to experience PMVT overnight and IV lidocaine was added. During the daytime hours he was ectopy free, but the following night he again experienced PMVT with appropriate device therapy. COVID-related myocarditis was suspected to have precipitated the electrical storm and elective intubation was being considered to help avoid further events. With further scrutiny, however, the VT appeared to be PVC/bradycardia initiated and exclusively occurring at night. The ICD was interrogated again & a sleep rate was noted to be programmed on at 50bpm starting at 10pm every night. The device was reprogrammed to VVIR 90 & the sleep rate feature turned off. No further VT was noted after these programming changes & the antiarrhythmic drips were discontinued. This case illustrates the real risk of bradycardia-dependent PMVT after AVJ ablation. In this case, not recognizing a bradycardia feature, sleep rate, being left on after AVJ ablation contributed to VT storm. With the myriad of programming features & options in contemporary pacing devices, it is important to program sleep & hysteresis features off after AVJ ablations & potentially in patients initiated on QT prolonging medications.