Wavefront curvature analysis derived from preprocedural imaging can identify the critical isthmus in patients with
Edward J Ciaccio1, Nicolas Cedilnik2, Henry H Hsia3
1Department of Medicine, Division of Cardiology, College of Physicians and Surgeons, Columbia University, New York, New York.
Insights
Left ventricular wall thickness variations, measured using computed tomography (CT), can help pinpoint reentrant ventricular tachycardia (VT) circuits. This imaging approach aids in localizing VT isthmuses in postinfarction patients.
Area of Science:
- Cardiology
- Medical Imaging
- Electrophysiology
Background:
- Functional conduction block can occur where activation wavefronts are convexly shaped.
- Postinfarction reentrant ventricular tachycardia (VT) poses a significant clinical challenge.
Purpose of the Study:
- To assess if left ventricular (LV) wall thickness from contrast-enhanced computed tomography (CT) can localize areas of functional conduction block in postinfarction VT.
- To correlate LV wall thickness variations with VT circuit morphology.
Main Methods:
- Evaluated 6 patients undergoing catheter ablation for postinfarction VT.
- Used CT imaging with inHEART processing to determine LV wall thickness (T) and approximated wavefront curvature (ΔT/T).
- Compared CT-derived maps of T and ΔT/T with electrophysiological (EP) study data on VT activation times.
Main Results:
- LV wall near the VT isthmus was thin (micrometers).
- Regions of high ΔT/T (wall thickness change) coincided with lateral isthmus boundaries where conduction block occurred.
- ΔT/T at boundaries was significantly larger than at the isthmus midline and global LV mean (P <.001).
Conclusions:
- Ventricular tachycardia wavefront curvature, influenced by source-sink mismatch, depends on ventricular wall thickness.
- High wavefront curvature areas, identified by ΔT/T, may help locate VT isthmuses in infarct border zones using preprocedural CT imaging.
Background:
Where activation wavefront curvature is convexly shaped, functional conduction block can occur.
Objective:
The purpose of this study was to determine whether left ventricular (LV) wall thickness determined from contrast-enhanced computed tomography (CT) is useful in localizing such areas in clinical postinfarction reentrant ventricular tachycardia (VT).
Methods:
We evaluated data from 6 patients who underwent catheter ablation for postinfarction VT. CT imaging with inHEART processing was conducted 1-3 days before electrophysiological (EP) study to determine LV wall thickness (T). Activation wavefront curvature was approximated as ΔT/T, where ΔT represents wall thickness change. During EP study, bipolar LV VT electrograms were acquired using a high-density mapping catheter, and activation times were determined. Maps of T, ΔT/T, and VT activation were subsequently compared using statistical analyses.
Results:
Two of 6 cases exhibited dual circuit morphologies, resulting in a total of 8 VT morphologies analyzed. The LV wall near the VT isthmus location tended to be thin, on the order of a few hundred micrometers. Regions of largest ΔT/T partially coincided with the lateral isthmus boundaries where electrical conduction block occurred during VT. ΔT/T at the boundaries, measured from imaging, was significantly larger compared to values at the isthmus midline and to the global LV mean value (P <.001).
Conclusion:
Wavefront curvature measured by ΔT/T and caused by source-sink mismatch is dependent on ventricular wall thickness. Areas of high wavefront curvature partly coincide with and may be helpful in locating the VT isthmus in infarct border zones using preprocedural imaging analysis.
Related Concept Videos
01:17Imaging Studies for Cardiovascular System I:Echocardiography
Indications: Echocardiography is utilized to diagnose heart failure, valve disorders, and myocardial infarction. It also assesses cardiac structures' size, shape, and motion, evaluates...
01:28Imaging Studies for Cardiovascular System V: CT
01:23Mitral Stenosis II: Clinical features and Diagnostic Tests
01:30Dysrhythmias V: Evaluating Dysrhythmias