Non-invasive assessment of left ventricular activation delay for identifying cardiac resynchronization therapy...

Ultra-high-frequency electrocardiogram (UHF-ECG) which visualizes electrical ventricular dyssynchrony may be a valuable tool for improving the selection and treatment of patients with indication to cardiac resynchronization therapy (CRT).

This study aimed to compare non-invasive assessment of left ventricular (LV) delay using UHF-ECG with invasive QLV in CRT candidates, and to evaluate whether UHF-ECG can identify patients who will achieve resynchronization and LV reverse remodeling after biventricular CRT.

Consecutive patients undergoing CRT at 2 centers were included. QLV was measured in basal, midventricular, and apical LV segment. UHF-ECG LV delay was measured from QRS onset to local activation in leads V5-V8. Global LV dyssynchrony (lv-DYS) was assessed during spontaneous rhythm and pacing from the earliest activation to the latest activation in leads V5-V8 and was used to identify CRT responders.

48 patients were included (75% male, age 67 ± 12 years, LV ejection fraction 31 ± 6%, QRSd 167 ± 20 ms). UHF-ECG in V8, V7, and V6 did not differ from QLV in the basal, midventricular, or apical segments (mean differences: 3 ± 14 ms, P = .52; -3 ± 17 ms, P = .18 and 0 ± 17 ms, P = .92) and strong correlation was observed between them (r = 0.84, P < .001). The lv-DYS strongly correlated with the longest QLV (r = 0.76, P < .001). Patients with baseline lv-DYS >58 ms showed a more significant reduction in lv-DYS and were more often responders to CRT than patients with shorter values (Δlv-DYS -70 ms vs -8 ms, and responders 97% vs 32%).

UHF-ECG enables non-invasive assessment of QLV and can help with identification of patients who will benefit from CRT.