Cardiac Resynchronization Guided by Ultra-High-Frequency ECG Maps

Here we present a technique based on 14-lead ultrahigh-frequency electrocardiogram (UHF-ECG, 5 kHz) able to measure the immediate effect of cardiac resynchronization therapy (CRT) settings on electrical ventricular dyssynchrony.Resting UHF-ECGs were sequentially recorded during different CRT settings: CRT OFF, CRT ON, VV delays 0, -20, -40 ms, and SMART sensing (Boston Scientific) in 33 patients. Electrical depolarization maps were computed from signal-averaged UHF-ECGs in the frequency band 150-1000 Hz. The horizontal axis of each map indicates time and the vertical axis indicates the activation location (V1-V8 lead). The red areas show the location-time of the maximal volume of simultaneously depolarized myocardial cells.The optimal CRT setting is characterized by a narrow and vertical activation pattern. Optimal CRT setting selected by a physician from electrical depolarization maps corresponded to the minimal mechanical intraventricular delay obtained from echocardiography in 61% of patients; in 27% of patients the difference was within a 10 ms interval.UHF-ECG depolarization maps represent a useful tool for the selection and setting of optimal cardiac resynchronization therapy.