MP-453092-11 LONG TERM FOLLOW-UP OF HIGH-RISK PATIENTS WITH NEGATIVE PROGRAMMED VENTRICULAR STIMULATION TESTING AND THE IMPACT OF DELAYED-ENHANCEMENT CARDIAC MAGNETIC RESONANCE IMAGING

Abstract

Programed ventricular stimulation (PVS) to induce monomorphic ventricular tachycardia (VT) is a risk stratification tool in patients with a variety of established or suspected cardiac conditions. Patients who are non-inducible for VT may yet be at risk for adverse arrhythmia related events, particularly in the presence of cardiac scar. To investigate the long-term outcomes of real-world patients with negative PVS and examine the role of cardiac scaring on long-term risks of arrhythmia recurrence. Consecutive patients with negative PVS testing and who underwent delayed enhancement cardiac magnetic resonance imaging (DE-CMR) for risk stratification were included. All patients underwent placement of implantable cardiac monitors (ICM) and were followed. Survival analysis was performed to investigate the impact of DE-CMR findings on survival free from adverse arrhythmic events. Ninety-one patients were included (age 60.3±14.8 years, women n=44(48.4%), ejection fraction 58.2±9.2%, cardiomyopathy n=27(29.7%), positive DE-CMR scar n= 54(59%)). Indications included non-sustained VT/premature ventricular contractions (PVC) (n=67), syncope (n=36), mitral valve prolapse (n=10), or muscular dystrophy (n=2). Patients were followed for 1.4±1.5 years during which 18 patients (20%) experienced clinically significant VT (n=12), syncope due to bradycardia (n=5), or death due to pulseless electrical activity (n=1). Baseline characteristics between those with and without adverse events were similar (P>0.05); however, the presence of cardiac scar on DE-CMR was associated with an increased risk of adverse events (HR 4.0 95%CI [1.2-14.3], P<0.03, log rank P =0.019). In a real-world cohort with long-term follow up, adverse arrhythmic outcomes occurred in 20% of patients with high-risk features despite non-inducibility for VT on PVS, and this risk was significantly greater in patients with positive DE-CMR scar. Long term-monitoring, including the use of ICM, may be appropriate in these patients.