Left ventricular regional remodeling and lead position during cardiac resynchronization therapy

摘要

BackgroundCardiac resynchronization therapy (CRT) induces segmental left ventricular (LV) remodeling. The LV lead position (LV-LP) affects response to CRT and remodeling. ObjectiveWe aimed to assess segmental remodeling concordant, adjacent, and remote to LV-LP using cardiac computed tomography (CT). MethodsWe included patients from the Empiric Versus Imaging-Guided Left Ventricular Lead Placement in Cardiac Resynchronization Therapy trial. Dynamic cardiac CT was performed at baseline and after 6 months. We assessed systolic wall thickening (WT) and exact LV-LP from the CT scans according to a 16-segment model.Response to CRTwas defined as ≥15% reduction in LV end-systolic volume. ResultsA total of 107 consecutive patients were included. The change in WT from baseline to follow-up was ?19% (95% confidence interval [CI] ?25% to ?13%;P< .001) in concordant segments, ?0.1% (95% CI ?5% to 5%;P= .97) in adjacent segments, and 20% (95% CI ?17% to 23%;P< .001) in remote segments. Diastolic wall thickness changed only marginally. Twenty patients (19%) were nonresponders at follow-up. In nonresponders with nonischemic cardiomyopathy, we observed a significant reduction in WT in concordant and adjacent segments with no increase in WT in remote segments. ConclusionDuring CRT, systolic WT increases in segments remote to LV-LP, decreases in concordant segments, and remains unchanged in adjacent segments. Only marginal changes occur in wall thickness. In nonresponders with nonischemic cardiomyopathy, deleterious changes in segmental myocardial function occur, and further studies on how to treat these patients best are warranted.