236Electrical ventricular dyssynchrony parameter able to predict CRT response, MADIT-CRT trial

Abstract

Purpose of study: To introduce a new ECG parameter for the identification of electrical ventricular dyssynchrony (DYS) and to study its association with heart failure progress (HF) or death in cardiac resynchronization therapy (CRT) patients. Methods: Ten-minute resting supine high-resolution 12-lead ECG was recorded before CRT in 663 LBBB patients enrolled in a MADIT-CRT trial. The signal-averaged QRS amplitude envelopes were computed for leads V1 to V6 and 3 bandwidths: 150- 250, 250-350 and 150-350 Hz. The DYS was measured as the mean delay between V1 and V6 maximums and centers of mass over all frequency bands. DYS represents electrical depolarization activation delay (in milliseconds) between the mid-septum and left ventricular lateral wall. Higher DYS corresponds to higher dyssynchrony. Results: 109 LBBB patients met the MADIT-CRT primary endpoint - HF or death (18f, 66±12 yrs) and 554 did not (186f, 64±11 yrs). Kaplan-Meier survival curves are presented below using four quartiles of the DYS parameter value: DYS-Q1 < 32 ms (low dyssynchrony), DYS-Q2 ≥ 32 and < 51 ms, DYS-Q3 ≥ 51 and < 66 ms and DYS-Q4 ≥ 66 ms (high dyssynchrony). Conclusions: DYS-Q1 predicts a probability of HF or death during CRT three times as high and DYS-Q2 twice as high as DYS-Q3 and DYS-Q4. DYS has the potential to be an important marker for selection of LBBB patients who will benefit from CRT. (Figure Presented).