Transcatheter Myocardial Needle Chemoablation During Real-Time Magnetic Resonance Imaging

Radiofrequency ablation for rhythm disorders is limited by the inability instantaneously to visualize and monitor ablation lesions and by the mismatch between immediate injury and irreversible conduction block. Magnetic resonance imaging (MRI) thermometry only approximates the extent of irreversible lesions. Late-gadolinium enhancement (LGE) MRI correlates with histological lesion volume but can only be performed once per procedure and is not a surrogate for real-time lesion monitoring during ablation. Furthermore, scar size by LGE several months post ablation is ≤50% smaller than that measured immediately post ablation. Not only does the lesion contract during fibrotic healing but LGE after radiofrequency energy injury probably reflects both the necrotic core and enhancement of a surrounding edematous penumbra. Radiofrequency ablation for ventricular tachycardia (VT) is further limited by the mismatch between thickness of left ventricular (LV) myocardium and shallowness of radiofrequency lesions. Critical peri-infarct substrate can be deep within the myocardium and difficult to ablate via endocardial or epicardial approaches. Failure to achieve permanent transmural tissue destruction is a common cause of therapeutic failure. MRI tissue characterization techniques can identify pathological rhythm substrate tissues,