Congenital heart diseaseCohort study
Isochronal Versus Electrogram-Based Conduction Velocity Estimation to Predict Inducible Monomorphic Ventricular Tachycardia in Repaired Tetralogy of Fallot
- Retrospective cohort subanalysis of the CATAPULT-TOF registry
- multivariable logistic regression
- receiver operating characteristic analyses
Authors' conclusion
ISO-CVi was independently associated with inducible MMVT and is measured with less variability than legacy EGM-CVi methods in a real-world sample. If external validity is confirmed, ISO-CVi may represent a more standardized method of isthmus CV estimation that could be broadly implemented across centers.
Study context
- Population
- Patients with repaired tetralogy of Fallot undergoing electrophysiology study before transcatheter pulmonary valve replacementpatients with tetralogy of Fallot who underwent pretranscatheter pulmonary valve replacement electrophysiology study
- Participants
- Seventy patients
- Exposure
- Isochronal CV index (ISO-CVi) compared to traditional EGM-CVi in predicting inducible ventricular tachycardia
- Outcome
- Inducible monomorphic ventricular tachycardia (MMVT) at electrophysiology study
Main finding
As reported in the abstract
Inducible MMVT
24 (34%)
Observational data: associations, not effects.
Further findings
| Outcome | odds ratio (per 0.1 m/s increase) (95% CI) | P value | |
|---|---|---|---|
| ISO-CVi association with MMVT (multivariable analysis) · multivariable analysis | 0.31 (0.13–0.63) | P = 0.004 | |
| 0.10.31310Odds ratio (log scale) |
Coefficient of variation
| Outcome | ISO-CVi | EGM-CVi | Estimate | P value |
|---|---|---|---|---|
| Median ISO-CVi, with versus without MMVT · lower in those with MMVT | P < 0.001 | |||
| Median EGM-CVi, with versus without MMVT · did not differ between groups | P = 0.055 | |||
| Coefficients of variation | 46% | 79% |
- ISO-CVi association with MMVT (multivariable analysis) — Sensitivity at a threshold of 0.22 m/s
- 88%
- ISO-CVi association with MMVT (multivariable analysis) — Specificity at a threshold of 0.22 m/s
- 70%
- Median ISO-CVi, with versus without MMVT: with MMVT median 0.17 m/s
- Median ISO-CVi, with versus without MMVT: without MMVT median 0.30 m/s
- Median EGM-CVi, with versus without MMVT: with MMVT median 0.43 m/s
- Median EGM-CVi, with versus without MMVT: without MMVT median 0.70 m/s
Original publication
Isochronal Versus Electrogram-Based Conduction Velocity Estimation to Predict Inducible Monomorphic Ventricular Tachycardia in Repaired Tetralogy of Fallot. Circ Arrhythm Electrophysiol. Published 6 August 2026. doi:10.1161/circep.125.014548
Summarised from the published abstract; every number is checked against it