Clinical Electrophysiology -> Ventricular Arrhythmias -> Experimental methods D-PO01 - Featured Poster Session (ID 11) Poster

D-PO01-005 - Noninvasive Cardiac Radioablation Paradoxically Improves Ventricular Mechanics As Assessed By Cardiac Mri (ID 877)

 R. Navara: Nothing relevant to disclose.
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Background: Noninvasive cardiac radioablation has been used for treatment-refractory VT. We hypothesized that radioablation would impair cardiac function.
Objective: Assess cardiac function and segmental strain changes after radioablation using magnetic resonance imaging (CMR), and correlate with segments targeted for radioablation.
Methods: Patients received a single 25 Gray fraction to a discrete ventricular target as part of the ENCORE-VT prospective trial. CMRs were obtained before treatment, 3 days and 3 months after treatment (n=9 patients). Scans were analyzed in blinded fashion using automated software (Medis) for left ventricular systolic (LVESV) and diastolic (LVEDV) volumes, ejection fraction (LVEF), and strain globally and segmentally.
Results: At 3 days, all 9 patients demonstrated decreased LVESV and 8/9 had decreased LVEDV (Panel A). Global measures of cardiac function improved in the majority of patients, including LVEF (6/9), longitudinal strain (7/9), and circumferential strain (6/9). At 3 months, half of the patients continued to have improved LV size and LVEF. Global strain patterns slightly worsened in the three patients with the largest radiation targets (105-208 mL). Many of the segments that demonstrated greatest improvement were also the segments treated with radioablation (Panel B).
Conclusion: Cardiac radioablation is associated with an unexpected acute improvement in ventricular mechanics, observed as early as three days after treatment using CMR. Understanding the molecular mechanisms of this positive remodeling effect may open new avenues for heart failure treatment beyond VT suppression.