Cardiac Resynchronization Therapy Is Associated with Reductions in Left Atrial Volume and Inappropriate ICD Therapy in MADIT-CRT
There are no prior studies assessing the relationship between left atrial volume and inappropriate ICD therapy following treatment with cardiac resynchronization therapy.
We hypothesized that patients randomized to CRT-D in the MADIT-CRT trial who had significant left atrial volume (LAV) reductions would have reduced risks of inappropriate ICD therapy.
Cardiac resynchronization remodeling was assessed by measuring LAV change between baseline and 12-month echocardiograms in 751 CRT-D treated patients. Patients were stratified into quartiles based on percent reduction of LAV change: High LAV responders were those in the highest three quartiles of LAV reduction (LAV reduction >21%) and low LAV responders were those in the lowest quartile of LAV reduction (LAV reduction <21%). Clinical factors associated with >21% reduction in LAV were evaluated by linear regression analysis.
In Cox proportional-hazards regression analyses, high LAV responders had a 39% reduction in the risk of inappropriate therapy (hazard ratio 0.61, p=0.04) and LBBB patients exhibited an even greater risk reduction in inappropriate therapy (hazard ratio 0.51, p=0.02) compared to low LAV responders during follow-up extending up to 3 years after the 12-month echocardiogram. High LAV responders also had a significantly lower risk of heart failure or death during follow-up than low LAV responders.
A ≥21% reduction in LAV with cardiac resynchronization therapy is associated with significant reductions in inappropriate ICD therapy and in heart failure or death during a 3-year follow-up.
Full-textDOI: · Available from: Anne-Christine Huth Ruwald, Sep 10, 2015
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ABSTRACT: ICDs have been demonstrated to be highly effective in the primary prevention of sudden death, but inappropriate shocks (IS) occur frequently and represent one of the most important adverse effects of ICDs. The aim of this study was to analyze IS and identify the clinical predictors and prognostic implications of ISs in a real-world primary prevention ICD population. This multicenter retrospective study was performed in 13 centers with experience in the field of ICD implantation (at least 30 per year) and ICD follow-up in Spain. All consecutive patients who underwent ICD implantation for primary prevention between January 2008 and May 2014 were included. One-thousand-sixteen patients were included, and 4 (0.39%) were lost to follow-up. Two-hundred-seventeen (21.4%) patients suffered from shock; 69 (6.8%) of these patients experienced IS, and 154 (15.4%) experienced appropriate shocks (AS). Age (<65years, hazard ratio (HR) 2.588 [95% CI 1.282-5.225]; p=0.008), history of atrial fibrillation (HR 2.252 [95% CI 1.230-4.115]; p=0.009), non-ischemic myocardiopathy (HR 2.258 [95% CI 1.090-4.479]; p=0.028), and cardiac resynchronization therapy (HR 0.385 [95% CI 0.200-0.740]; p=0.004) were identified as IS predictors in a multivariate analysis. IS was not associated with rehospitalization due to heart failure, myocardial infarction, cardiovascular mortality or all-cause mortality. This analysis of our national registry identified the independent IS predictors of age, atrial fibrillation history and cardiac resynchronization therapy and suggests that ISs are not linked to poorer clinical endpoints. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.International Journal of Cardiology 09/2015; 195:188-194. DOI:10.1016/j.ijcard.2015.05.146 · 4.04 Impact Factor