2701 - Long-Term Outcomes of a Phase I/II Trial for Stereotactic Arrhythmia Radioablation in Ventricular Tachycardia

Monday, September 30, 2024

3:00 PM – 4:00 PM ET

Location: Hall C

Screen: 24

Presenter(s)

Jing Li, MD

Chengdu, Sichuan

J. Li¹, Q. Chen², X. Zhang³, W. Wei³, Q. Xiao⁴, G. Li⁵, F. Xu^6,7, and S. Bai⁸; ¹Department of Radiotherapy Physics & Technology, West China Hospital, Sichuan University, Chengdu, China, ²Department of cardiology, West China Hospital, Sichuan University, Chengdu, China, ³West china hospital, Sichuan university, chengdu, China, ⁴Radiotherapy Physics and Technology Center, Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China, ⁵Radiation Physics Center, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China, ⁶West China Hospital of Sichuan University, Chengdu, Sichuan, China, ⁷Lung Cancer Center, West China Hospital, Sichuan University, Chengdu, China, ⁸Division of Radiation Physics, Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China

Purpose/Objective(s): Stereotactic arrhythmia radioablation (STAR) is an emerging non-invasive alternative for arrhythmia. This phase I/II clinical trial aimed to assess the long-term efficacy and safety of STAR in patients with refractory ventricular tachycardia (VT).

Materials/

Methods: The prospective phase I/II trial commenced in April 2021. Eligible patients were diagnosed with VT, had ineffective anti-arrhythmia drugs, and undergone unsuccessful endocardial and/or epicardial radiofrequency ablation. The arrhythmogenic substrate was localized based on electrocardiograph and previous electroanatomic mapping, then the margin of motion, setup, and delivery was expanded for planning target volume (PTV). A single fraction of 25 Gy was delivered to the PTV using a stereotactic radiosurgery arc. Study visits occurred at day 3, week 6, month 12, and annually thereafter. The primary outcome was to estimate the long-term efficacy of STAR by 24-hour Holter monitor at each study visit and monitoring the safety of STAR through the incidence of adverse events.

Results: As of July 2023, 8 patients were enrolled, with a median age of 58 years [21-74] and a median follow-up of 16 months [2-27]. The PTVs were located in the epicardium, with an average volume of 89.4 ± 27.7 ml. The median VT burden before STAR, 6 weeks after STAR, and at the latest follow-up was 34.5 [2-125], 0.5 [0-67], 0 [0-465], respectively. In 1 patient, the number of VT episodes increased after an initial reduction, while the others showed a significant and sustained reduction in VT episodes. Postoperative gastritis was reported in 1 patient with STAR for left ventricular lateral and posterior wall, and reflux esophagitis was reported in another patient with STAR for aortomitral continuity both of which resolved promptly.

Conclusion: Long-term follow-up confirms that STAR provides continuous relief for VT; however, individual patient responses may vary, with some experiencing transient decline in arrhythmia episodes. No radiation-related serious adverse events occurs during the follow-up period.

Abstract 2701 – Table 1

			No. of episodes of ventricular tachycardia
Patient No.	Age	Follow-up time	Before STAR	6-wk blanking period	Latest period
1	53	27	37	2	7
2	30	25	2	0	0
3	67	22	6	2	0
4	74	20	-	1	0
5	75	11	39	0	0
6	50	12	32	0	3
7	21	5	-	0	0
8	63	2	125	67	465