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Free wall activation delay (FWD) is a new simplified tissue Doppler index that reflects mechanical dyssynchrony. The association of FWD on heart failure (HF) hospitalizations or death after cardiac resynchronization therapy (CRT), however is unknown.
To test the hypothesis that the presense of baseline FWD is associated with reduced HF hospitalization or death after CRT.
We studied 321 consecutive CRT patients with routine indications. FWD was the average tissue Doppler time-to peak longitudinal velocity from QRS onset in 8 basal and mid free wall segments from 3 apical views (pre-defined cut-off ≥ 240 ms). Also, speckle tracking radial strain delay (RSD) from midventricular views was measured. (pre-defined cut-off ≥ 130 ms). Outcome events were predefined as first HF hospitalization or death.
Both FWD and RSD were analyzable in 269 pts (84%), 65±11 yrs, with QRS 159±27 ms and ejection fraction 24±6%. There were 65 HF hospitalizations and 27 deaths over 2 yrs. Both FWD and RSD predicted HF hospitalization or death (HR 0.49, 95%CI 0.33-0.72, p < 0.001 and HR 0.47 95%CI 0.30-0.75, p=0.001). FWD was additive to RSD for predicting outcome (p = 0.002): for both indices positive vs. both negative, HR was 0.2 (p < 0.001), one positive vs. both negative, HR was 0.43 (p = 0.008).
FWD had additive value to clinical risk factors and RSD in predicting mortality and morbidity in CRT patients. These observations have clinical implications for risk stratification of CRT patients.
Poster Sessions, Expo North
Monday, March 11, 2013, 9:45 a.m.-10:30 a.m.
Session Title: Imaging: CRT/New Technology
Abstract Category: 18. Imaging: Echo
Presentation Number: 1312-332
- 2013 American College of Cardiology Foundation