If the results are supported by more definitive trials, “it could have quite significant implications,” one expert says.
BERLIN, GERMANY—Ventricular tachycardia (VT) ablation before primary prevention implantable cardioverter defibrillator (ICD) placement improves clinical outcomes in a selected group of patients with ischemic cardiomyopathy who are at high risk for ventricular arrhythmias. Showing the results of the randomized PREVENTIVE VT trial that showed benefits.
The study included patients with reduced ejection fraction and chronic total occlusion (CTO) in the infarct-related artery who were not candidates for revascularization. Patients who randomly underwent VT ablation before ICD implantation had significantly lower rates of ICD treatment or hospitalization related to ventricular arrhythmias compared to patients who received a defibrillator without ablation (16.7% vs. 43.3%).
David Žižek, MD (University Medical Center Ljubljana, Slovenia), who reported this data at the 2024 European Heart Rhythm Society Congress, said that identifying patients at high risk of ventricular arrhythmias requiring VT ablation as a primary prevention strategy. emphasized the importance of It may make sense because of the potential risks involved.
These results from a trial involving 60 patients “encourage not only an efficient and safer catheter ablation technique, but also a new imaging modality that has the potential to establish this concept in clinical practice. “This warrants appropriate future research to explore this,” he said.
Prophylactic VT trial
Although ICDs have been proven to save lives, appropriate shocks are associated with decreased quality of life and adverse clinical outcomes. There are questions about the usefulness and when to perform VT substrate ablation, with some data showing that intervention in patients with documented ventricular arrhythmias before ICD implantation reduces arrhythmia recurrence. , said Žižek.
Although evidence is mixed regarding the impact of such approaches on clinical outcomes, previous studies have demonstrated that delayed ablation is associated with poorer prognosis, lower success rates, and increased surgical complications. I am.
This raises the question of whether stromal ablation is useful as a primary prevention strategy, Žižek noted.
He said that before testing this concept in a randomized trial, it was important to identify the appropriate patient population, and that patients with CTO in the infarcted area and deemed unsuitable for revascularization had ventricular It was pointed out that the incidence of arrhythmia was high.
Therefore, in the PREVENTIVE VT trial, researchers from four Slovenian centers will enroll 60 patients (mean age approximately 67 years, 92% male) with ischemic cardiomyopathy, infarction-related CTO, and primary prevention ICD indications. registered. The average LVEF was approximately 35%. Almost half (48%) had a history of symptomatic MI, 43% had a history of PCI, and 8% had a history of surgical revascularization.
Patients randomly assigned to VT ablation underwent a procedure before ICD implantation with the aim of high-density remapping and removal of any abnormal electrograms after VT non-inducible.
The primary endpoint was time to ICD treatment or unplanned ventricular arrhythmia-related hospitalization, with a reduced risk for patients who underwent ablation before receiving an ICD (adjusted HR 0.32) over a mean follow-up of 44.7 months. , 95% CI 0.11). -0.91).
The trend toward less ICD treatment was not significant (16.7% vs 40%; HR 0.35; 95% CI 0.12-1.02). All nine unplanned hospitalizations for symptomatic ventricular arrhythmias occurred in patients in the ICD-only group.
Unplanned cardiac hospitalizations (including ventricular arrhythmia and heart failure hospitalizations) were less frequent after ablation and ICD implantation (13.3% vs 53.3%; HR 0.22; 95% CI 0.07-0.68). There were 6 thunderstorm cases, all in the ICD-only group.
There were no significant differences between study groups in heart failure hospitalization, cardiovascular death, or all-cause death. Professor Žižek said the safety of the ablation was reasonable, reporting two ablation-related complications (6.6%). One case was a complete atrioventricular block that required implantation of a cardiac resynchronization therapy defibrillator, and the other was an ischemic stroke that resolved without outcome.
The promise of precision medicine
William Stephenson, MD, Vanderbilt University Medical Center in Nashville, Tennessee, who served as a discussant after Žižek’s presentation, said the concept of performing catheter ablation in patients receiving ICDs has not been tested in clinical trials. He pointed out. Smash VT This study showed that in patients with prior MI receiving an ICD, VT substrate ablation reduced arrhythmias without affecting mortality. Although this was a groundbreaking trial, it did not change practice, Stevenson said.
He wondered whether prophylactic ventricular tachycardia, which has demonstrated a reduction in ventricular tachycardia and arrhythmia hospitalizations using a similar strategy, would impact how clinicians manage these patients. did.
“For this to be clinically applicable, it has to be extremely safe,” Stevenson said, highlighting two adverse events in the ablation arm of the small trial. Although atrioventricular block is expected in patients with VT and septal stroma, “stroke is probably a little more of a concern,” he added. But again, his one incident in a small court case. ”
He called for further research into the usefulness of this strategy. “But what I’m particularly passionate about about this is that this is an example of where our field of precision medicine, identifying the right treatments for the right patients, is headed. Because I think so,” Stevenson said. “This is a very special subgroup of patients who are at high risk for VT – infarcted patients whose infarcted artery is occluded, and there is an opportunity for this patient to make a difference.”
Speaking with TCTMD, Stevenson cited reducing hospitalizations as a key element of the trial. “There is no indication that it improves mortality, and the study is underpowered in that regard, but there is a significant effect in reducing hospitalizations, which could have a fairly large impact,” he said.
Stevenson points out that the approach studied here would have been much more difficult 10 to 20 years ago. “The reason this is worth considering is that there have been significant technological advances in catheter ablation and mapping that allow most practicing electrophysiologists to perform this.”
