Septal Rebound Stretch is a Strong Predictor of Outcome After Cardiac Resynchronization Therapy

BackgroundSeptal rebound stretch (SRSsept) is a distinctive characteristic of discoordination-related mechanical inefficiency. We assessed how intermediate- and long-term outcome after cardiac resynchronization therapy (CRT) relate to baseline SRSsept.Methods and ResultsA total of 101 patients (age 65 ± 11 years, 69 men, 18 New York Heart Association (NYHA) class IV, QRS 173 ± 23 ms) scheduled for CRT underwent clinical assessment, echocardiography, and brain-type natriuretic peptide (BNP) measurements before and 6.4 ± 2.3 months after CRT. Baseline SRSsept (all systolic stretch after initial shortening in the septum) was quantified by speckle tracking echocardiography. Primary composite end point was death, urgent cardiac transplantation, or left ventricular assist device implantation at the end of the study. Secondary end points were intermediate-term (6 months) response, quantified as decreases in left ventricular end-systolic volume (ΔLVESV) and BNP (ΔBNP). After a mean clinical follow-up of 15.6 ± 9.0 months; 23 patients had reached the primary end point. Baseline SRSsept (hazard ratio [HR] 0.742; 95% confidence intervals [CI] 0.601–0.916, P < .01]) was independently associated with a better outcome and NYHA class (HR 5.786: 95% CI 2.341–14.299, P < .001) with a worse outcome. Contrary to baseline NYHA class, baseline SRSsept was an independent predictor of both ΔLVESV (beta 0.53; P < .001) and ΔBNP (beta 0.29; P < .01). Intermediate-term ΔLVESV and ΔBNP were associated with a favorable long-term outcome.ConclusionsSRSsept at baseline is a strong, independent predictor of long-term prognosis after CRT and of improvements in left ventricular remodeling and neurohormonal activation at intermediate term.