This will be a single-blinded, dose-escalation, cohort study in 60 subjects allocated sequentially to 1 of 3 cohorts A, B, or C. Forty-five subjects will be randomized to receive transendocardial delivery of MPC treatment, and 15 subjects will be randomized to receive standard-of-care treatment without MPC administration. The fifteen subjects randomized to receive standard of care without needle injection will serve as the study's control population and will undergo mock mapping and verbal injection scripts.