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Updated: Jul 5, 2026
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Baseline scintigraphic abnormalities by myocardial perfusion imaging predict echocardiographic response to cardiac
1Cardiovascular Institute, Department of Medicine, University of Pittsburgh, Medical Center, Pittsburgh, PA 15213-2582, USA.
Insights
Myocardial perfusion defects negatively impact cardiac resynchronization therapy (CRT) response in nonischemic cardiomyopathy (NICM). Patients with fewer perfusion defects showed better CRT echocardiographic outcomes, highlighting the importance of perfusion imaging in NICM.
Area of Science:
- Cardiology
- Medical Imaging
- Heart Failure Treatment
Background:
- Myocardial scarring impacts cardiac resynchronization therapy (CRT) response in coronary artery disease.
- The effect of perfusion abnormalities in nonischemic cardiomyopathy (NICM) on CRT outcomes is not well-defined.
Purpose of the Study:
- To investigate how myocardial perfusion abnormalities affect echocardiographic outcomes of CRT in NICM patients.
- To determine if resting perfusion defects influence CRT efficacy in nonischemic cardiomyopathy.
Main Methods:
- Included 21 NICM patients undergoing CRT implantation and Thallium-201 SPECT myocardial perfusion imaging (MPI).
- Quantitatively assessed perfusion using a summed perfusion score (SPS) for 17 myocardial segments.
- Evaluated echocardiographic response (LVEF increase) before and after CRT in 15 patients.
Main Results:
- Echocardiographic response to CRT was observed in 53.3% of patients.
- Patients with a lower SPS (<=6) had a significantly higher response rate (100%) compared to those with higher SPS (>6) (30.0%) (OR 3.33, p=0.01).
- All non-responders exhibited inferior perfusion defects; defect density near the LV lead did not significantly affect CRT efficacy.
Conclusions:
- Significant myocardial perfusion defects are associated with a poorer echocardiographic response to CRT in NICM.
- These findings suggest that MPI may help predict CRT response in NICM patients.
- Prospective studies and histopathological correlation are recommended for confirmation.
Background:
Significant myocardial scar in the posterolateral left ventricle (LV) has been associated with a diminished response to cardiac resynchronization therapy (CRT) in patients with coronary artery disease, but the effects of resting perfusion abnormalities in nonischemic cardiomyopathy (NICM) are yet to be described.
Hypothesis:
We sought to characterize the effect of myocardial perfusion abnormalities upon echocardiographic outcomes of CRT in patients with NICM.
Methods:
Twenty-one patients (mean age 64.4 +/- 13.3; 71.4% male; mean left ventricular ejection fraction [LVEF] 20.2 +/- 6.9%) with NICM who underwent CRT implantation and Thallium-201 single positron emission computed tomography (SPECT) myocardial perfusion imaging (MPI) were included. MPI studies were read quantitatively, assigning each of 17 myocardial segments a perfusion score (0-4) and cumulatively generating a summed perfusion score (SPS). The LV lead position was determined by chest radiography. Echocardiograms were performed both before and after (median 12 mo) CRT in 15 patients.
Results:
Echocardiographic response, defined as > or = 15% relative increase in LVEF, was documented in 8 (53.3%) of 15 patients. All patients (5/5) with an SP < or =6 responded to CRT, whereas only 30.0% (3/10) with an SPS > or = 6 responded (odds ratio 3.33 [95% confidence interval {CI} 1.29-8.59]; p = 0.01). All nonresponders had inferior perfusion defects. Defect density adjacent to the LV lead tip had little demonstrable effect upon CRT efficacy.
Conclusions:
The presence of significant myocardial perfusion defects negatively influences echocardiographic response to CRT in NICM. These findings warrant prospective confirmation and histopathological correlation with explanted hearts.
