PMID- 23873141
OWN - NLM
STAT- MEDLINE
DCOM- 20131126
LR  - 20130821
IS  - 1941-3084 (Electronic)
IS  - 1941-3084 (Linking)
VI  - 6
IP  - 4
DP  - 2013 Aug
TI  - Transseptal conduction as an important determinant for cardiac resynchronization 
      therapy, as revealed by extensive electrical mapping in the dyssynchronous canine 
      heart.
PG  - 682-9
LID - 10.1161/CIRCEP.111.000028 [doi]
AB  - BACKGROUND: Simple conceptual ideas about cardiac resynchronization therapy 
      assume that biventricular (BiV) pacing results in collision of right and left 
      ventricular (LV) pacing-derived wavefronts. However, this concept is contradicted 
      by the minor reduction in QRS duration usually observed. We investigated the 
      electric mechanisms of cardiac resynchronization therapy by performing detailed 
      electric mapping during extensive pacing protocols in dyssynchronous canine 
      hearts. METHODS AND RESULTS: Studies were performed in anesthetized dogs with 
      acute left bundle-branch block (LBBB, n=10) and chronic LBBB with 
      tachypacing-induced heart failure (LBBB+HF, n=6). Activation times (AT) were 
      measured using LV endocardial contact and noncontact mapping and epicardial 
      contact mapping. BiV pacing reduced QRS duration by 21+/-10% in LBBB but only by 
      5+/-12% in LBBB+HF hearts. Transseptal impulse conduction was significantly slower 
      in LBBB+HF than in LBBB hearts (67+/-9 versus 44+/-16 ms, respectively), and in both 
      groups significantly slower than transmural LV conduction ( approximately 30 ms). In both 
      groups QRS duration and vector and the epicardial AT vector amplitude and angle 
      were significantly different between LV and BiV pacing, whereas the endocardial 
      AT vector was similar. During variation of atrioventricular delay while LV 
      pacing, and ventriculo-ventricular delay while BiV pacing, the optimal 
      hemodynamic effect was achieved when epicardial AT and QRS vectors were minimal 
      and endocardial AT vector indicated LV preexcitation. CONCLUSIONS: Due to slow 
      transseptal conduction, the LV electric activation sequence is similar in LV and 
      BiV pacing, especially in failing hearts. Optimal hemodynamic cardiac 
      resynchronization therapy response coincides with minimal epicardial asynchrony 
      and QRS vector and LV preexcitation.
FAU - Strik, Marc
AU  - Strik M
AD  - Department of Physiology, Cardiovascular Research Institute Maastricht, 
      Maastricht University, Maastricht, Limburg, The Netherlands.
FAU - van Deursen, Caroline J M
AU  - van Deursen CJ
FAU - van Middendorp, Lars B
AU  - van Middendorp LB
FAU - van Hunnik, Arne
AU  - van Hunnik A
FAU - Kuiper, Marion
AU  - Kuiper M
FAU - Auricchio, Angelo
AU  - Auricchio A
FAU - Prinzen, Frits W
AU  - Prinzen FW
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20130719
PL  - United States
TA  - Circ Arrhythm Electrophysiol
JT  - Circulation. Arrhythmia and electrophysiology
JID - 101474365
SB  - IM
MH  - Action Potentials
MH  - Animals
MH  - Bundle-Branch Block/diagnosis/physiopathology/*surgery
MH  - *Cardiac Resynchronization Therapy
MH  - Disease Models, Animal
MH  - Dogs
MH  - Electrophysiologic Techniques, Cardiac
MH  - Epicardial Mapping
MH  - Female
MH  - Heart Conduction System/physiopathology/*surgery
MH  - Heart Failure/diagnosis/physiopathology/*surgery
MH  - Hemodynamics
MH  - Male
MH  - Time Factors
MH  - Ventricular Function, Left
MH  - Ventricular Function, Right
OTO - NOTNLM
OT  - cardiac resynchronization therapy
OT  - electrophysiology
OT  - heart failure
OT  - left bundle-branch block
OT  - pacing
EDAT- 2013/07/23 06:00
MHDA- 2013/12/16 06:00
CRDT- 2013/07/23 06:00
PHST- 2013/07/23 06:00 [entrez]
PHST- 2013/07/23 06:00 [pubmed]
PHST- 2013/12/16 06:00 [medline]
AID - CIRCEP.111.000028 [pii]
AID - 10.1161/CIRCEP.111.000028 [doi]
PST - ppublish
SO  - Circ Arrhythm Electrophysiol. 2013 Aug;6(4):682-9. doi: 
      10.1161/CIRCEP.111.000028. Epub 2013 Jul 19.