Case Report: Repeated Stereotactic Radiotherapy of Recurrent Ventricular Tachycardia: Reasons, Feasibility, and Safety

Abstract

Stereotactic body radiotherapy (SBRT) has been reported as an attractive option for cases of failed catheter ablation of ventricular tachycardia (VT) in structural heart disease. However, even this strategy can fail for various reasons. For the first time, this case series describes three re-do cases of SBRT which were indicated for three different reasons. The purpose in the first case was the inaccuracy of the determination of the treatment volume by indirect comparison of the electroanatomical map and CT scan. A newly developed strategy of co-registration of both images allowed precise targeting of the substrate. In this case, the second treatment volume overlapped by 60% with the first one. The second reason for the re-do of SBRT was an unusual character of the substrate–large cardiac fibroma associated with different morphologies of VT from two locations around the tumor. The planned treatment volumes did not overlap. The third reason for repeated SBRT was the large intramural substrate in the setting of advanced heart failure. The first treatment volume targeted arrhythmias originating in the basal inferoseptal region, while the second SBRT was focused on adjacent basal septum without significant overlapping. Our observations suggested that SBRT for VT could be safely repeated in case of later arrhythmia recurrences (i.e., after at least 6 weeks). No acute toxicity was observed and in two cases, no side effects were observed during 32 and 22 months, respectively. To avoid re-do SBRT due to inaccurate targeting, the precise and reproducible strategy of substrate identification and co-registration with CT image should be used.

Inflammation and fibrosis characterize different stages of myocardial remodeling in patients after stereotactic body radiotherapy of ventricular myocardium for recurrent ventricular tachycardia

“…What are the upstream events inducing apoptosis of cardiomyocytes several weeks after irradiation remains to be clarified by further experimental and clinical studies. This hypothesis is in line with our clinical experience about delayed effect of SBRT for VT [ 20 , 21 ].…”

Retrograde coronary venous ethanol ablation of ventricular tachycardia in a patient after aortic valve replacement and failed both radiofrequency ablation and stereotactic radiotherapy

“…Catheter ablation of ventricular arrhythmias arising from the LV summit may be challenging for many reasons, including the complex intramural substrate, epicardial fat and surrounding vessels preventing appropriate and safe energy delivery (5). In the case of the inaccessible substrate, several alternative treatment strategies have been proposed such as bipolar ablation with normal or half-normal saline irrigation, SBRT and alcohol ablation of vessels supplying the targeted substrate (2)(3)(4)(5)(6)(7). SBRT has emerged as a promising non-invasive strategy in cases of failed RF ablation.…”

“… 5 In the case of the inaccessible substrate, several alternative treatment strategies have been proposed, such as bipolar ablation with normal or half-normal saline irrigation, SBRT, and alcohol ablation of vessels supplying the targeted substrate. 2 , 3 , 4 , 5 , 6 , 7 SBRT has emerged as a promising noninvasive strategy in cases of failed RF ablation. The main limitation of SBRT is predominantly delayed and unpredictable clinical effects with substantial recurrence rates.…”

“…Such scenario may require repeated ablation procedures with an uncertain outcome. In the case of failed RF ablation, several unconventional treatment modalities, including bipolar RF ablation, stereotactic body radiation therapy (SBRT) and ethanol ablation have been proposed (2)(3)(4)(5). We report a case of successful retrograde coronary venous ethanol ablation (RCVEA) of VT in a patient after aortic valve replacement and previously failed both bipolar RF ablation and SBRT.…”

“…In the case of failed RF ablation, several unconventional treatment modalities, including bipolar RF ablation, stereotactic body radiation therapy (SBRT), and ethanol ablation, have been proposed. 2 , 3 , 4 , 5 We report a case of successful retrograde coronary venous ethanol ablation (RCVEA) of VT in a patient after aortic valve replacement and previously failed both bipolar RF ablation and SBRT.

Key Teaching Points Management of ventricular arrhythmias arising from the left ventricular (LV) summit may be challenging.

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