009 Uncovering the mechanism of the paradoxical association between cardiac dyssynchrony and better survival in heart failure. (16th May 2012)

• Record Type: Journal Article
• Authors: Jabbour, R J; Shah, J; Mayet, J; Francis, D P
• Is Part Of: Heart. Volume 98(2012)Supplement 1
• Page Start: A9
• Page End: A9
• Publication Date: 2012-05-16
• Subjects: Heart failure -- dyssychrony -- CRT; Heart -- Diseases -- Treatment -- Periodicals; Cardiology -- Periodicals; 616.12
• DOI: 10.1136/heartjnl-2012-301877b.9
• Languages: English
• ISSNs: 1355-6037

Abstract

Abstract : Introduction: Paradoxically, dyssynchrony before CRT is associated with a better prognosis. We tested whether this was dependent on device implantation or on how the cohort was defined (EF ≤35 vs All-comers). Methods: 419 patients (67.8±11.3 years, 79.2% males, 127 deaths) with heart failure had echocardiographic assessment of mechanical dyssynchrony and were followed up (median 3.1 years). Results: 135 had dyssynchrony and 62 received CRT. The mean EF was 33.1±15.0%; 157 (35.2%) had an EF >35%. Among patients with EF≤35% (n=249), shorter aortic pre-ejection time (ie, less dyssynchrony) was associated with a worse prognosis (p<0.05). All dyssynchrony markers were higher in survivors (p<0.001 by sign test, upper panel). EF was not prognostic and depressed by dyssynchrony (r=−0.4, p<0.001). By examining all patients (regardless of EF); the association between dyssynchrony and better survival disappeared (p>0.05, lower panel). EF was restored to its prognostic significance (p=0.02). Taking a different approach to define poor ventricular function—using low S-wave velocity—EF had prognostic significance (p<0.05) and dyssynchrony markers were non-prognostic (p>0.05). Conclusion: Dyssynchrony predicts better survival in low EF groups because dyssynchrony artifactually lowers EF without damaging survival. The effect is independent of CRT. Replacement of EF with dyssynchrony-neutral measures of LV function, for example, peak S-wave velocity would avoid the appearance that dyssynchrony is favourable.