Relationship of echocardiographic dyssynchrony to long-term survival after cardiac resynchronization therapy.
BACKGROUND
The ability of echocardiographic dyssynchrony to predict response to cardiac resynchronization therapy (CRT) has been unclear.


RESULTS
A prospective, longitudinal study was designed with predefined dyssynchrony indexes and outcome variables to test the hypothesis that baseline dyssynchrony is associated with long-term survival after CRT. We studied 229 consecutive class III to IV heart failure patients with ejection fraction ≤35 and QRS duration ≥120 milliseconds for CRT. Dyssynchrony before CRT was defined as tissue Doppler velocity opposing-wall delay ≥65 milliseconds, 12-site SD (Yu Index) ≥32 milliseconds, speckle tracking radial strain anteroseptal-to-posterior wall delay ≥130 milliseconds, or pulsed Doppler interventricular mechanical delay ≥40 milliseconds. Outcome was defined as freedom from death, heart transplantation, or left ventricular assist device implantation. Of 210 patients (89) with dyssynchrony data available, there were 62 events: 47 deaths, 9 transplantations, and 6 left ventricular assist device implantations over 4 years. Event-free survival was associated with Yu Index (P=0.003), speckle tracking radial strain (P=0.003), and interventricular mechanical delay (P=0.019). When adjusted for confounding baseline variables of ischemic origin and QRS duration, Yu Index and radial strain dyssynchrony remained independently associated with outcome (P<0.05). Lack of radial dyssynchrony was particularly associated with unfavorable outcome in those with QRS duration of 120 to 150 milliseconds (P=0.002).


CONCLUSIONS
The absence of echocardiographic dyssynchrony was associated with significantly less favorable event-free survival after CRT. Patients with narrower QRS duration who lacked dyssynchrony had the least favorable long-term outcome. These observations support the relationship of dyssynchrony and CRT response.
Gorcsan
John
J
University of Pittsburgh, Scaife 564, 200 Lothrop St, Pittsburgh, PA 15213-2582, USA. gorcsanj@upmc.edu
Oyenuga
Olusegun
O
Habib
Phillip J
PJ
Tanaka
Hidekazu
H
Adelstein
Evan C
EC
Hara
Hideyuki
H
McNamara
Dennis M
DM
Saba
Samir
S
D002304:Cardiac Pacing, Artificial / Q000379:methods*; D058406:Cardiac Resynchronization Therapy / Q000379:methods* / Q000401:mortality; D018572:Disease-Free Survival; D004452:Echocardiography / Q000379:methods; D005260:Female; D006333:Heart Failure / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008944:Mitral Valve Insufficiency / Q000503:physiopathology / Q000628:therapy; D015588:Observer Variation; D011336:Probability; D011446:Prospective Studies; D013318:Stroke Volume / Q000502:physiology*; D015996:Survival Rate; D017741:Survivors