Results from the PAUSE-SCD trial show a significant reduction in the risk of recurrent ventricular tachycardia (VT), cardiovascular hospitalization and death when catheter ablation is used as an early first-line treatment for patients with structural heart disease.
The PAUSE-SCD trial is the first VT ablation trial to include patients with non-ischemic cardiomyopathy and to be conducted across Asia. The results of this landmark trial were presented today as cutting-edge science at the Heart Rhythm Society’s 2021 Annual Meeting (HRS 2021, July 28-31, Boston, USA and virtual).
As the study was conducted in Asia, the largest populated continent at risk for sickle cell disease, VT patients with non-ischemic cardiomyopathy were included due to a higher prevalence compared to ischemic cardiomyopathy.
The international, multicenter, randomized controlled trial was conducted at 11 sites in China, Japan, Korea, and Taiwan in collaboration with Chicago Medical University (Chicago, USA) which served as the coordinating center of the study. A total of 121 patients with structural heart disease or monomorphic VT indicated for treatment with an implantable cardioverter defibrillator (ICD) were recruited. Patients were randomized 1:1 for ablation within 90 days of ICD implantation or medical treatment.
Patients who refused ICD treatment were followed in a prospective registry after autonomous ablation treatment. The primary endpoint included a triple composite of VT recurrence, cardiovascular hospitalization, and death. The study was conducted over a period of six years with a median patient follow-up of 31 months.
Key trial results reveal that catheter ablation as first-line treatment within 90 days of ICD treatment reduced the relative risk of VT recurrence, cardiovascular hospitalization and death by 42% in various etiologies of structural heart disease. During the median follow-up period, the primary outcome occurred in 45% of patients who underwent ablation and 59% of those treated with conventional medical therapy (relative risk 0.58, 95% confidence interval, 0.35‒0.96; P=0.036). Ablation was performed on average two days before ICD implantation (IQR 5 days before-14 days after). There were 8% procedural complications in the ablation group.
“This is just one of three clinical trials to provide a comprehensive review of catheter ablation as a preventative measure for patients at risk for life-threatening sudden cardiac events,” said Roderick Tung, University of Chicago, Chicago, USA and lead author. . “Ablation has always been considered a palliative strategy of last resort and presenting it as a therapy concomitant with the implantation of an ICD is a potentially significant paradigm shift. It is also the first to include VT patients without prior myocardial infarction as well as the first to include more contemporary procedural strategies, such as high-resolution mapping and epicardial approaches. We hope that these findings will influence future guidelines that tend toward earlier use of catheter ablation versus medical therapy in the treatment of patients.
Additionally, study results showed that the ablation registry indicated that enrolled patients who did not receive ICDs had greater freedom from recurrent VT compared to medical treatment without significant differences in mortality. The authors express that this opens the door to scientific questioning as to whether ablation without defibrillator treatment may be acceptable in highly selected patients.
Additionally, they note that defibrillator therapy is not affordable for many people around the world, which reinforces the importance of future studies that could potentially randomize patients with nonischemic cardiomyopathy, a group that is not has not shown a consistent survival advantage with ICD implantation, compared to stand-alone ablation therapy.