Correlation Between Functional Substrate Mapping and Cardiac Computed Tomography-Derived Wall Thinning for...

Area of Science:

• Cardiovascular Imaging
• Electrophysiology
• Cardiac Surgery

Background:

• Functional substrate mapping aids ventricular tachycardia (VT) ablation by identifying arrhythmogenic tissue.
• Cardiac computed tomography angiography (CTA) derived wall thinning and wall thickness channels (WTCs) correlate with low voltage areas and VT isthmuses.
• The relationship between substrate mapping, wall thinning, and WTCs in infarct-related cardiomyopathy (ICM) and non-infarct-related cardiomyopathy (NICM) is not well-defined.

Purpose of the Study:

• To correlate cardiac CTA-derived myocardial wall thinning with functional VT substrate mapping using isochronal late activation mapping.
• To investigate the utility of wall thinning and WTCs in identifying VT substrate in ICM and NICM patients.

Main Methods:

• 34 patients with ICM or NICM undergoing VT ablation with pre-procedure cardiac CTA were analyzed.
• Myocardial wall thinning was segmented in 1-5 mm layers.
• Areas of wall thinning and WTCs were spatially correlated with deceleration zones (DZs) from endocardial isochronal late activation maps.

Main Results:

• ICM patients exhibited greater wall thinning compared to NICM patients (P < 0.001).
• Primary DZs were predominantly located on areas of wall thinning in ICM (94.1%) and NICM (50% with thinning).
• DZs were located near WTCs in 59% of ICM and 56% of NICM patients, with low positive predictive values for WTCs (22.5% in ICM, 37.8% in NICM).

Conclusions:

• Myocardial wall thinning is highly sensitive for detecting functional VT substrate in ICM patients.
• WTCs demonstrate modest sensitivity but low positive predictive value for localizing DZs in both ICM and NICM.
• Wall thinning may enhance VT mapping efficiency in ICM, while WTCs are insufficient for pinpointing wavefront discontinuities.