Cardiac resynchronization therapy cures dyssynchronopathy in canine left bundle-branch block hearts.
OBJECTIVE
We investigated to what extent biventricular pacing (BVP) can normalize LV function and remodeling, induced by isolated left bundle branch block (LBBB).


RESULTS
In 16 dogs LBBB was induced. Eight animals were followed for 16 weeks and in 8 animals BVP was started after 8 weeks. LV pressure, LV geometry (2Dechocardiography), systolic circumferential shortening (CSsys, MRI tagging) and myocardial blood flow (MBF, microspheres) was measured. * and # indicate P < 0.05 compared to pre-LBBB and 8 weeks of LBBB, respectively. Data is presented relative to pre-LBBB values (mean +/- SEM). BVP increased LV dP/dt|max from 78 +/- 5%* to 86 +/- 5%*# (immediately) and 89 +/- 6%# (after 8 weeks) and normalized regional differences in CSsys and MBF. After 8 weeks of BVP, LV end-diastolic volume (EDV) was reduced from 123 +/- 3%* to 109 +/- 6%# and LV lateral wall mass was reduced from 128 +/- 5%* to 113 +/- 3%*#. The acute increase in LV dP/dt|max upon BVP correlated with LV EDV and LV wall mass after 8 weeks of BVP.


CONCLUSIONS
In canine hearts with long-term isolated LBBB, BVP largely reverses global and regional functional and structural abnormalities induced by LBBB.
Vernooy
Kevin
K
Department of Physiology, Cardiovascular Research Institute Maastricht, PO Box 616, 6200 MD, Maastricht, the Netherlands. K.Vernooy@fys.unimaas.nl
Cornelussen
Richard N M
RN
Verbeek
Xander A A M
XA
Vanagt
Ward Y R
WY
van Hunnik
Arne
A
Kuiper
Marion
M
Arts
Theo
T
Crijns
Harry J G M
HJ
Prinzen
Frits W
FW
D000818:Animals; D002037:Bundle-Branch Block / Q000503:physiopathology / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D003331:Coronary Vessels / Q000502:physiology; D004285:Dogs; D005260:Female; D006439:Hemodynamics; D018810:Magnetic Resonance Angiography; D008297:Male; D010138:Pacemaker, Artificial; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology / Q000628:therapy*; D020257:Ventricular Remodeling / Q000502:physiology