Journal editorial: Computed tomography-guided ablation of ventricular tachycardia: how predictable are VT circuits?

Yes, so the In Your Heart trial was an investigator-initiated, open-label, multi-center, randomized controlled trial conducted in 14 high-volume EP centers across Austria, France, Germany, and Switzerland.

And a total of 113 patients with prior myocardial infarction and clinically significant VT were enrolled and randomized in a one-to-one fashion to a CT-guided VT ablation strategy or a conventional electroanatomical mapping-guided ablation approach.

All patients underwent contrast-enhanced ECG-gated CARIC CT prior to randomization, after which a blinded core lab independently performed 3D segmentation and annotated myocardial wall thinning and wall thickness heterogeneity-based thickness isthmus channels.

The acute procedural endpoint in both groups was the VT non-inducibility of anemomorphic VT. and the primary endpoint of the trial was total procedure duration.

Secondary endpoints included safety, VT inducibility at the end of the procedure, arrhythmia burden and VT-free survival at 12 months.

The CT-guided arm operators imported the pre-annotated CT model into their 3D mapping system and performed ablation in sinus rhythm without induction of VT using a structured linear lesion approach, intentionally connecting the most thin scar boundaries to one another or to fixed anatomical structures.

After CT-guided ablation, a VT induction attempt was made and additional individual ablation was performed if needed.

In the conventional arm, operators first performed LV voltage and electrogram substrate mapping using high-density multi-electrode mapping catheters at their discretion to identify areas of abnormal substrate, such as dense low-voltage scar, local abnormal ventricular activity, late potentials or border zone slow conduction correlates, and then delivered operator-determined focal and or linear ablation lesion, either in sinus rhythm or during induced VTE.

So the authors found that CT-guided ablation achieved a significant reduction in total procedure duration, corresponding to a 28-minute absolute reduction and a 19% relative reduction in the modified intention-to-treat population.

When the CT-guided workflow was adhered to strictly per protocol, total procedure duration was further reduced, representing a 42-minute absolute reduction and a 28% relative reduction.

Major intra-procedural complications were infrequent and comparable between both groups, occurring in two patients in the conventional ablation arm and one patient in the CT-guided arm.

Overall, in-hospital adverse events remained clinically similar between both groups.

Acute procedural efficacy assessed by final monomorphic VT non-inducibility at case completion remained high and did not differ between arms.

12-month VT-free survival was numerically 67% in the conventional group versus 77% in the CT-guided group, a difference that did not reach significance.