Arrhythmias & electrophysiology
The Transmural Activation Interval in Dilated Cardiomyopathy: A New Mapping Tool for Intramural Ventricular Tachycardia (VT) Substrates
Authors' conclusion
In patients with DCM and VTs, the transmural activation interval is a novel, voltage-independent mapping tool that may improve intramural substrate identification and VT ablation.
Study context
- Population
- Patients with dilated cardiomyopathy (DCM) and a narrow QRS complex who underwent endocardial and epicardial VT ablationpatients with DCM, 3 control subjects with idiopathic ventricular arrhythmias · DCM 27 · control subjects 3
- Participants
- 27 patients
- Comparison
- Spatial relation of epicardial critical isthmus sites (CIS) and VT-related sites (VRS) to areas with transmural activation delay (TAD), late gadolinium enhancement on cardiac magnetic resonance imaging, and low unipolar voltage (<8.27 mV)
- DCMn = 27
- control subjectsn = 3
Main finding
As reported in the abstract
Transmural activation interval (TAI)
DCM
21
median · IQR 9-35 milliseconds · milliseconds
Further findings
Epicardial area with TAD (>39.9 milliseconds)
- Median epicardial surface area with TAD, % of total epicardial surface
- 7.7%
- CIS contained
- 95%
- VRS contained
- 82%
- Based on the 99th percentile in 3 control subjects
Late gadolinium enhancement-derived scar area
- Median scar area, % of epicardial surface
- 29%
- CIS contained
- 85%
- VRS contained
- 84%
Area with low unipolar voltage
- Area, % of epicardial surface
- 8.6%
- CIS contained
- 72%
- VRS contained
- 58%
Baseline characteristics
- Mean age
- 49 ± 16 years
- Left ventricular ejection fraction
- 38% ± 11%
- QRS duration
- 96 ± 10 milliseconds
Original publication
The Transmural Activation Interval in Dilated Cardiomyopathy: A New Mapping Tool for Intramural VT Substrates. JACC Clin Electrophysiol. Published 13 February 2026. doi:10.
Summarised from the published abstract; every number is checked against it