Transcatheter Myocardial Needle Chemoablation During Real-Time Magnetic Resonance Imaging

Abstract

Background Radiofrequency ablation for ventricular arrhythmias is limited by inability to visualize tissue destruction, by reversible conduction block resulting from edema surrounding lesions, and by insufficient lesion depth. We hypothesized that transcatheter needle injection of caustic agents doped with gadolinium contrast under real-time magnetic resonance imaging (MRI) could achieve deep, targeted and irreversible myocardial ablation which would be immediately visible. Methods and Results Under real-time MRI guidance, ethanol or acetic acid was injected into the myocardium of 8 swine using MRI-conspicuous needle catheters. Chemoablation lesions had identical geometry by in vivo and ex vivo MRI as well as histopathology, both immediately and after 12(7–17) days. Whereas ethanol caused stellate lesions with patchy areas of normal myocardium, acetic acid caused homogeneous circumscribed lesions of irreversible necrosis. Ischemic cardiomyopathy was created in 10 additional swine by sub-selective transcoronary ethanol administration into non-contiguous territories. After 12(8–15) days, real-time MRI guided chemoablation — with 2–5 injections to create a linear lesion —successfully eliminated the isthmus and local abnormal voltage activities. Conclusions Real-time MRI guided chemoablation with acetic acid enabled the intended arrhythmic substrate, whether deep or superficial, to be visualized immediately and ablated irreversibly. In an animal model of ischemic cardiomyopathy, obliteration of a conductive isthmus both anatomically and functionally, and abolition of local abnormal voltage activities in areas of heterogeneous scar was feasible. This represents the first report of MRI guided myocardial chemoablation, an approach that could improve efficacy of arrhythmic substrate ablation in the thick ventricular myocardium.

Magnetic resonance imaging guidance for the optimization of ventricular tachycardia ablation

“…Transcatheter needle chemoablation to target intra-mural substrate has generated interest to improve the efficacy of ablation in selected patient cohorts. In this regard, Rogers et al 76 have delivered chemoablation with ethanol or acetic acid under real-time MRI guidance in swine with immediate visualization of lesions and subsequent EAM confirmation of conductive isthmus disruption which appears promising.…”

Real‐time MRI guidance of cardiac interventions

“…The failure to create durable transmural lesions has been held largely responsible for the high recurrence rates following many complex ablations, particularly VT and AF. 29,33,34 MR may be used to assess acute ablation lesions, 7,33,35,36 and consequently enable targeted "top-up" ablation at selected locations. More recently, interest has focused on real-time imaging of lesion formation, and with further developments it may even be possible to titrate energy delivery to ensure the creation of adequate ablation lesions.…”

Pathology after a combination of sequential and simultaneous unipolar radiofrequency ablation of ventricular tachycardia in a postmortem heart with cardiac sarcoidosis

“…There are some other approaches for creating transmural lesions, such as bipolar ablation, needle ablation, and transcoronary ethanol ablation. [10][11][12][13][14][15] Bipolar radiofrequency current was applied between two distal ablation catheter electrodes on both sides of the myocardium. A high effectiveness of a bipolar ablation has been reported; however, there are some disadvantages as compared to the SURF ablation.…”

“…[5][6][7][8][9] To overcome the limited lesion creation with RFA, some techniques to improve it have been developed, such as simultaneous unipolar radiofrequency (SURF) ablation, bipolar ablation, needle ablation, and transcoronary ethanol ablation. [10][11][12][13][14][15][16][17] In this case report, we evaluated the pathologic features after a SURF ablation of a VT in a postmortem heart with cardiac sarcoidosis.…”