Substrate Characterization and Outcomes of Ventricular Tachycardia Ablation in <i>TTN (Titin)</i> Cardiomyopathy
Bibliographic record
Abstract
Background: Truncating variants of the TTN ( titin ) gene are a leading cause of dilated cardiomyopathy and have been associated with an increased risk of ventricular arrhythmias. This study evaluated the substrate distribution and the acute and long-term outcomes of patients with TTN -related cardiomyopathy undergoing ventricular tachycardia (VT) ablation. Methods: This multicenter registry included 15 patients with dilated cardiomyopathy (age, 59±11 years; 93% men; ejection fraction, 30±12%) and genotypically confirmed truncating variants of the TTN gene who underwent VT ablation between July 2014 and 2020. Results: All patients presented with sustained monomorphic VT, including electrical storm in 4 of them. A median of 2 VTs per patient were induced during the procedure (cycle length, 318±68 ms), and the predominant morphologies were left bundle branch block with inferior axis (39%) and right bundle branch block with inferior axis (29%). A complete map of the left ventricle was created in 12 patients and showed voltage abnormalities mainly at the periaortic (92%) and basal septal regions (58%). A preprocedural cardiac magnetic resonance imaging was available in 13 patients, and in 11, there was evidence of left ventricular delayed gadolinium enhancement, with predominantly midmyocardial distribution. Sequential ablation from both sides of the septum was required in 47% of patients to target septal intramural substrate, and epicardial ablation was performed in 20%. At the end of the procedure, the clinical VT was noninducible in all patients, while in 3 cases, a nonclinical VT was still inducible. After a follow-up of 26.5±23.0 months, 53% of patients experienced VT recurrence, 20% received transplant or mechanical circulatory support, and 7% died. Conclusions: The arrhythmogenic substrate in TTN -related cardiomyopathy involves the basal septal and perivalvular regions. Long-term outcomes of catheter ablation are modest, with high recurrence rate, likely related to an intramural location of VT circuits.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".