Electrocardiographic imaging (ECGI) provides noninvasive assessment of myocardial electrical activation and may complement structural imaging in ischemic cardiomyopathy (ICM). An observational analysis published in the Heart Rhythm evaluated the relationship between ECGI-derived markers and ventricular arrhythmogenic substrate in 72 participants: 29 with ICM referred for ventricular tachycardia (VT) ablation, 17 with ICM and implantable cardioverter-defibrillators without prior VT, and 26 controls.

Regional activation dispersion (rAD) and pseudo-regional conduction velocity (pseudo-rCV) were analyzed during sinus rhythm and compared with scar defined by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). At the patient level, the mean rAD of the three regions with highest activation dispersion differentiated patients with ICM with versus without prior VT using a cutoff ≥60.0 ms (AUC 0.75; sensitivity 75.9%; P=0.005). An rAD cutoff ≥39.5 ms differentiated ICM patients from controls (AUC 0.93). Scarred regions showed higher rAD (46.3 ± 2.2 ms vs 30.1 ± 1.7 ms; P<.001) and lower pseudo-rCV (149.9 ± 3.0 cm/s vs 165.7 ± 2.4 cm/s; P<.001).

In a subgroup of 16 patients undergoing electroanatomic mapping, ECGI identified 70.4% of deceleration zones, with higher rAD in affected regions (64.9 ± 5.4 ms vs 43.1 ± 3.1 ms; P<.001). At the patient level, higher rAD differentiated ICM patients with prior VT (AUC 0.75) and distinguished ICM patients from controls (AUC 0.93).

rAD was associated with ventricular arrhythmogenic substrate and differentiated patients with and without prior VT in this observational study

As an observational study with modest sample size, findings require validation in larger prospective cohorts to determine prognostic utility.