Cardiac resynchronization therapy (CRT) can improve global left ventricular (LV) function.
However, limited data are available on regional LV contractility at rest and during
exercise. The aim of the present study was to prospectively investigate the effects
of CRT on regional LV ejection fraction (EF), global LVEF, and dyssynchrony, during
rest and exercise, using radionuclide angiography. A total of 32 consecutive patients
with heart failure and nonischemic cardiomyopathy underwent technetium-99m radionuclide
angiography with bicycle exercise immediately after CRT implantation (during spontaneous
rhythm and after CRT activation) and 3 months later. The regional EF was assessed
in the interventricular septum and the lateral wall (LW). Intraventricular dyssynchrony
was evaluated using Fourier phase analysis. During spontaneous rhythm, the EF was
severely depressed in the septum compared to in the LW. CRT improved septal EF at
rest and during exercise both at baseline (p <0.001) and after 3 months (p <0.05).
The basal LW EF decreased during CRT (p <0.05, both at rest and during exercise).
LV dyssynchrony decreased both at baseline and during follow-up, and the global LVEF
showed improvement only at 3 months (p <0.001). In conclusion, in patients with nonischemic
cardiomyopathy, CRT affects regional LV function by increasing the septal EF and reducing
LW contractility, both at rest and during exercise. This was associated with an improvement
in global LVEF and dyssynchrony.
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Article info
Publication history
Accepted:
March 22,
2010
Received in revised form:
March 22,
2010
Received:
January 23,
2010
Footnotes
This study was performed at S. Orsola-Malpighi Hospital, Bologna, Italy, and was supported in part by a grant from “Fondazione Luisa Fanti Melloni,” Bologna, Italy.
Identification
Copyright
© 2010 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
