Intraventricular dyssynchrony predicts mortality and morbidity after cardiac resynchronization therapy: a study using cardiovascular magnetic resonance tissue synchronization imaging.
OBJECTIVE
We aimed to assess a novel measure of left ventricular (LV) dyssynchrony, a cardiovascular magnetic resonance-tissue synchronization index (CMR-TSI), in patients with heart failure (HF). A further aim was to determine whether CMR-TSI predicts mortality and major cardiovascular events (MCE) after cardiac resynchronization therapy (CRT).


BACKGROUND
Cardiac dyssynchrony is a predictor of mortality in patients with HF. The unparalleled spatial resolution of CMR may render CMR-TSI a predictor of clinical benefit after CRT.


METHODS
In substudy A, CMR-TSI was assessed in 66 patients with HF (age 60.8 +/- 10.8 years, LV ejection fraction 23.9 +/- 12.1% [mean +/- SD]) and 20 age-matched control subjects. In substudy B, CMR-TSI was assessed in relation to clinical events in 77 patients with HF and with a QRS > or =120 ms undergoing CRT.


RESULTS
In analysis A, CMR-TSI was higher in patients with HF and a QRS <120 ms (79.5 +/- 31.2 ms, p = 0.0003) and in those with a QRS > or =120 ms (105.9 +/- 55.8 ms, p < 0.0001) than in control subjects (21.2 +/- 8.1 ms). In analysis B, a CMR-TSI > or =110 ms emerged as an independent predictor of the composite end points of death or unplanned hospitalization for MCE (hazard ratio [HR] 2.45; 95% confidence interval [CI] 1.51 to 4.34, p = 0.0002) or death from any cause or unplanned hospitalization for HF (HR 2.15; 95% CI 1.23 to 4.14, p = 0.0060) as well as death from any cause (HR: 2.6; 95% CI 1.29 to 6.73, p = 0.0061) and cardiovascular death (HR 3.82; 95% CI 1.63 to 16.5, p = 0.0007) over a mean follow-up of 764 days.


CONCLUSIONS
Myocardial dyssynchrony assessed by CMR-TSI is a powerful independent predictor of mortality and morbidity after CRT.
Chalil
Shajil
S
Department of Cardiology, Good Hope Hospital, Sutton Coldfield/Birmingham, West Midlands, England.
Stegemann
Berthold
B
Muhyaldeen
Sarkaw
S
Khadjooi
Kayvan
K
Smith
Russell E A
RE
Jordan
Paul J
PJ
Leyva
Francisco
F
D000368:Aged; D000704:Analysis of Variance; D002304:Cardiac Pacing, Artificial; D015150:Echocardiography, Doppler; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000401:mortality* / Q000628:therapy; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D012372:ROC Curve; D018570:Risk Assessment; D013318:Stroke Volume; D016019:Survival Analysis; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000401:mortality* / Q000628:therapy; D020257:Ventricular Remodeling / Q000502:physiology