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Ventricular volume changes are more accurate markers of acute response to CRT than contraction indices
Authors : E Boe (Oslo,NO), OA Smiseth (Oslo,NO), P Storsten (Oslo,NO), OS Andersen (Oslo,NO), J Aalen (Oslo,NO), M Eriksen (Oslo,NO), M Krogh (Oslo,NO), E Kongsgaard (Oslo,NO), EW Remme (Oslo,NO), H Skulstad (Oslo,NO)
E. Boe1
,
O.A. Smiseth2
,
P. Storsten1
,
O.S. Andersen1
,
J. Aalen1
,
M. Eriksen1
,
M. Krogh1
,
E. Kongsgaard2
,
E.W. Remme1
,
H. Skulstad2
,
1University of Oslo, Institute for Surgical Research - Oslo - Norway
,
2Oslo University Hospital, Department of Cardiology - Oslo - Norway
,
Background: Cardiac resynchronisation therapy (CRT) improves systolic function in left bundle branch block (LBBB). However, the magnitude of acute improvements in global ventricular contraction indices do not correlate consistently with long-term response to CRT.
Purpose: To determine the effect of CRT on contraction indices and ventricular volumes during LBBB by pressure-volume analysis.
Methods: In eight anaesthetised dogs, we measured left ventricular (LV) pressure by micromanometry and LV volume by sonomicrometry to calculate stroke work (SW), stroke volume (SV), peak rate of LV pressure rise (LV dP/dtmax) and ejection fraction (EF). LBBB was induced by radiofrequency ablation. Transient caval constrictions were performed to compare data at similar preloads.
Results: CRT decreased LV volumes significantly shown by a reduction in end-diastolic volume (EDV) from 83.2±21.4 to 79.5±21.1 (P<0.05) and end-systolic volume from 67.0±20.5 to 63.8±20.4 (P<0.05). There were negligible changes in SV, SW and EF whereas LV dP/dtmax increased moderately (Figure, left panels). When correcting for the reduction in preload, SV, SW and EF increased significantly (Figure, right panels). The magnitude of change in LV dP/dtmax was 3 times larger when using preload-corrected data.
Conclusions: CRT reduced preload shown by a significant reduction in EDV with little changes in EF, SW and SV. These findings suggest that LV volume changes rather than conventional contraction indices should be used to evaluate acute CRT response. These observations may explain some of the apparent inconsistency between acute response and long-term response to CRT.
ESC Professional Members, Association Members (Ivory & above) benefit from year-round access to all the resources from their respective Association, and to all content from previous years. Fellows of the ESC (FESC), and professionals in training or under 40 years old, who subscribed to a Young Combined Membership package benefit from access to all ESC 365 content from all events, all editions, all year long. Find out more about ESC Memberships here.
