Progression of XXXX after biventricular pacing: Is there a subgroup of "favorable nonresponders"?

@entity1 @entity712 @entity714
BACKGROUND: @entity714 ( @entity714 ) and dominant R wave in lead V1 (RV1) post-biventricular pacing (BiVp) are associated with better clinical outcomes. However, some @entity1 continue to deteriorate despite these favorable electrocardiographic changes. OBJECTIVE: We tested the hypothesis that baseline @entity714 and post-BiVp RV1 are associated with better cardiac function and clinical outcomes in @entity1 with progressive deterioration in @entity712 after BiVp ("clinical nonresponders") than in @entity1 without these electrocardiographic criteria. METHODS: Consecutive @entity1 with advanced @entity712 and BiVp were included. An increase in R-wave amplitude of over 4.5 times the baseline value was defined as RV1. Clinical outcome was survival free of heart transplantation and/or implantation of mechanical circulatory support. RESULTS: A total of 179 (100 (56%) with @entity714 ; 79 (44%) with non- @entity714 ) @entity1 with advanced @entity712 and BiVp were included. Of the 100 @entity1 with @entity714 , 67 (67%) developed RV1 (group 1) but 33 (33%) @entity1 did not develop RV1 (group 2). Of the 79 @entity1 with non- @entity714 , 49 (62%) developed RV1 (group 3) and the remaining 30 (38%) @entity1 did not develop RV1 (group 4). Changes in left ventricular ejection fraction and left ventricular end-systolic volume index were not significant in group 1, but deteriorated in the other groups (P < .05). The change in left ventricular end-systolic volume index was associated with the change in QRS duration and absence of RV1 (P < .01). Clinical outcome was most favorable in group 1 ( @entity714 and RV1). Changes in left ventricular ejection fraction, tricuspid annular plane systolic excursion, and right atrial pressure were associated with clinical outcomes. CONCLUSION: Despite progressive deterioration in @entity712 , @entity1 with @entity714 and RV1 post-BiVp demonstrate more stable cardiac function and more favorable clinical outcomes than did @entity1 with non- @entity714 with or without RV1 post-BiVp.
