Does ‘super-responder’ patients to cardiac resynchronization therapy still have indications for neuro-hormonal antagonists? Evidence from long-term follow-up in a single center

Background Whether cardiac resynchronization therapy super-responders (CRT-SRs) still have indications for neuro-hormonal antagonists or not remains uninvestigated.Methods We reviewed clinical data from 376 patients who underwent CRT implantation in Fuwai Hospital from 2009 to 2015 and followed up to 2017.CRT-SRs were defined by an improvement of the New York Heart Association functional class and left ventricular ejection fraction to ≥ 50% in absolute values at 6-month follow-up.All CRT-SRs were assigned into two groups on the basis of whether persistently receiving neuro-hormonal antagonists (NHA)(defined as angiotensin-converting enzyme inhibitors/ angiotensin receptor blockers and β-blockers) after 6-month follow-up and then we compared long-term outcome.Results A total of 60 patients met criteria for super-response.One of thirteen (7.7%) CRT-SRs without NHA had all-cause death,which also occurred in 2 of 47 (4.3%) in CRT-SRs with NHA (P = 0.526).However,3 of 13 (23.1%) CRT-SRs without NHA had heart failure (HF) hospitalization,1 of 47 (2.1%) CRT-SRs with NHA had this endpoint (P = 0.040).Besides,subgroup analysis indicated that,for ischemic etiology group,CRT-SRs receiving NHA had considerably lower incidence of HF hospitalization than those without NHA (0 vs.75%,P = 0.014),which was not observed in non-ischemic etiology group (2.6% vs.0,P = 1.000) during long-term follow-up.Conclusions Our study found that for ischemic etiology,compared with CRT-SRs with NHA,CRT-SRs without NHA were associated with a higher risk of HF hospitalization.However,for non-ischemic etiology,we found that CRT-SRs with NHA or without NHA at follow-up were associated with similar outcomes,which needed further investigation by prospective trials.

Cardiac electrical and mechanical synchrony of super-responders to cardiac resynchronization therapy

Background:Super-responders(SRs)to cardiac resynchronization therapy(CRT)regain near-normal or normal cardiac function.The extent of cardiac synchrony of SRs and whether continuous biventricular(BIV)pacing is needed remain unknown.The aim of this study was to evaluate the cardiac electrical and mechanical synchrony of SRs.Methods:We retrospectively analyzed CRT recipients between 2008 and 2016 in 2 centers to identify SRs,whose left ventricular(LV)ejection fraction was increased to≥50%at follow-up.Cardiac synchrony was evaluated in intrinsic and BIV-paced rhythms.Electrical synchrony was estimated by QRS duration and LV mechanical synchrony by single-photon emission computed tomography myocardial perfusion imaging.Results:Seventeen SRs were included with LV ejection fraction increased from 33.0±4.6%to 59.3±6.3%.The intrinsic QRS duration after super-response was 148.8±30.0 ms,significantly shorter than baseline(174.8±11.9 ms,P=0.004,t=3.379)but longer than BIV-paced level(135.5±16.7 ms,P=0.042,t=2.211).Intrinsic LV mechanical synchrony significantly improved after super-response(phase standard deviation[PSD],51.1±16.5°vs.19.8±8.1°,P<0.001,t=5.726;phase histogram bandwidth(PHB),171.7±64.2°vs.60.5±22.9°,P<0.001,t=5.376)but was inferior to BIV-paced synchrony(PSD,19.8±8.1°vs.15.2±6.4°,P=0.005,t=3.414;PHB,60.5±22.9°vs.46.0±16.3°,P=0.009,t=3.136).Conclusions:SRs had significant improvements in cardiac electrical and LV mechanical synchrony.Since intrinsic synchrony of SRs was still inferior to BIV-paced rhythm,continued BIV pacing is needed to maintain longstanding and synchronized contraction.