Document Detail

Left bundle branch block causes relative but not absolute septal underperfusion during exercise.
MedLine Citation:
PMID:  19734552     Owner:  NLM     Status:  MEDLINE    
AIMS: Left bundle branch block (LBBB) often causes septal perfusion defects in radionuclide myocardial perfusion imaging using exercise (Ex) but rarely using vasodilator stress. We studied whether this is due to an underlying structural disease inherent to spontaneous LBBB or whether it is also found in temporary LBBB induced by right ventricular pacing (PM) indicating a functional rather than a structural alteration.
METHODS AND RESULTS: Regional myocardial blood flow (MBF) at rest and at Ex was measured with 15O-H2O and PET in 10 age-matched healthy volunteers (controls), 10 LBBB patients and 10 PM patients with right ventricular pacing off and on (PM off and PM on). Although at Ex septal MBF tended to be higher in LBBB than in controls (3.04 +/- 1.18 vs. 2.27 +/- 0.72 mL/min/g; P = ns), the ratio septal/lateral MBF was 19% lower in LBBB than in controls (P < 0.05). Similarly, switching PM on at Ex decreased the ratio septal/lateral MBF by 17% (P < 0.005).
CONCLUSION: The apparent septal perfusion defect in LBBB is mainly due to a relative lateral hyperperfusion rather than to an absolute septal flow decrease. This pattern seems to be reversibly inducible by right ventricular pacing, suggesting a functional rather than a structural alteration.
Pascal Koepfli; Christophe A Wyss; Oliver Gaemperli; Patrick T Siegrist; Michael Klainguti; Tiziano Schepis; Mehdi Namdar; Markus Bechir; Tobias Hoefflinghaus; Firat Duru; Philipp A Kaufmann
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  European heart journal     Volume:  30     ISSN:  1522-9645     ISO Abbreviation:  Eur. Heart J.     Publication Date:  2009 Dec 
Date Detail:
Created Date:  2009-12-16     Completed Date:  2011-01-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8006263     Medline TA:  Eur Heart J     Country:  England    
Other Details:
Languages:  eng     Pagination:  2993-9     Citation Subset:  IM    
Cardiac Imaging, University Hospital, NUK C42, Raemistr. 100, CH-8091 Zurich, Switzerland.
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MeSH Terms
Bundle-Branch Block / physiopathology*,  radionuclide imaging,  therapy
Cardiac Pacing, Artificial
Cardiomyopathies / etiology*,  physiopathology
Case-Control Studies
Coronary Circulation / physiology*
Exercise / physiology*
Heart Septum / physiopathology*
Middle Aged
Positron-Emission Tomography

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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