on March 31, 2008
Published online before print March 31, 2008, doi: 10.1161/CIRCULATIONAHA.107.726711
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Submitted on February 22, 2007
From the Department of Cardiology and Institute of Postgraduate Medical Education and Research, Northwick Park Hospital, Harrow, UK. * To whom correspondence should be addressed. E-mail: roxysenior{at}cardiac-research.org.
Background—We aimed to investigate the cardiac effects of left bundle-branch block (LBBB) using myocardial contrast echocardiography (MCE) to ascertain the value of MCE for detecting coronary artery disease (CAD) and to uncover the mechanism that affects the accuracy of single-photon emission computed tomography (SPECT) in these patients. Methods and Results—Sixty-three symptomatic LBBB patients (group A), 10 left ventricular ejection fraction–matched control subjects without LBBB and no CAD (group B), and 10 normal control subjects (group C) underwent resting echocardiography. Rest and vasodilator MCE and SPECT were undertaken in LBBB patients. Septal (SW) and posterior wall (PW) thickness, thickening, quantitative myocardial blood flow (MBF), and MBF reserve were measured. SW/PW thickness and percentage thickening ratios were lower (P<0.01 and P<0.05, respectively) in group A compared with both groups B and C, but resting SW/PW MBF and MBF reserve ratios were similar in all 3 groups. MBF reserve but not MBF was reduced in groups A and B (2.2±0.7 versus 2.2±0.2; P=0.98) compared with group C (3.1±0.5; P<0.01). SW thickness was an independent predictor (P=0.006) of SPECT perfusion defects in LBBB patients without CAD. MCE (92%) had a sensitivity similar to SPECT (92%); however, the specificity of MCE (95%) was superior (P<0.0001) to SPECT (47%) for the detection of CAD. Conclusions—Despite asymmetrical reduction in SW thickness and function, MBF is preserved and MBF reserve is homogeneously reduced in LBBB patients with left ventricular systolic dysfunction. Because of partial volume effects, the accuracy of SPECT for detecting CAD was significantly compromised compared with MCE in this patient cohort.
Accepted on January 22, 2008
Effects of Left Bundle-Branch Block on Cardiac Structure, Function, Perfusion, and Perfusion Reserve. Implications for Myocardial Contrast Echocardiography Versus Radionuclide Perfusion Imaging for the Detection of Coronary Artery Disease
S. A. Hayat MBChB, MRCP,
Key words: bundle-branch block • coronary disease • echocardiography • nuclear medicine • perfusion
Related Article:
Circulation 2008 117: 1769.
This article has been cited by other articles:
 |
|
 |
|
  R Mizuno, S Fujimoto, Y Saito, and S Nakamura Depressed recovery of subendocardial perfusion in persistent heart failure after complete revascularisation in diabetic patients with hibernating myocardium Heart, May 1, 2009; 95(10): 830 - 834. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Senior, H. Becher, M. Monaghan, L. Agati, J. Zamorano, J. L. Vanoverschelde, and P. Nihoyannopoulos Contrast echocardiography: evidence-based recommendations by European Association of Echocardiography Eur J Echocardiogr, March 1, 2009; 10(2): 194 - 212. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Senior, M. Monaghan, M. L. Main, J. L. Zamorano, K. Tiemann, L. Agati, N. J. Weissman, A. L. Klein, T. H. Marwick, M. Ahmad, et al. Detection of coronary artery disease with perfusion stress echocardiography using a novel ultrasound imaging agent: two Phase 3 international trials in comparison with radionuclide perfusion imaging Eur J Echocardiogr, January 1, 2009; 10(1): 26 - 35. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Kaul Myocardial Contrast Echocardiography: A 25-Year Retrospective Circulation, July 15, 2008; 118(3): 291 - 308. [Full Text] [PDF]
|
|