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[Evaluation of right ventricular wall contractility in ischemic heart disease by cardiac computed tomography]
Insights
Cardiac CT effectively assesses right ventricular (RV) function in ischemic heart disease. Severe right coronary artery stenosis significantly impairs RV free wall contractility, detectable via CT imaging.
Area of Science:
- Cardiology
- Radiology
- Medical Imaging
Background:
- Ischemic heart disease can affect right ventricular (RV) function.
- Assessing RV contractility is crucial for understanding disease severity and progression.
- Current methods may have limitations in evaluating RV function in chronic ischemic conditions.
Purpose of the Study:
- To evaluate the utility of cardiac computed tomography (CT) in assessing right ventricular (RV) wall contractility in patients with ischemic heart disease.
- To correlate RV contractility parameters derived from CT with coronary angiography findings, specifically right coronary artery (RCA) stenosis.
- To determine if CT can identify RV ischemia in the chronic stages of ischemic heart disease.
Main Methods:
- One hundred and eight patients with ischemic heart disease (excluding acute myocardial infarction) underwent ECG-gated cardiac CT.
- RV wall contractility was assessed using long-axial and short-axial CT images, measuring RV area contraction rate, RV free wall shortening rate, and RV free wall thickness changes.
- CT-derived parameters were compared with findings from coronary angiography and left ventriculography.
Main Results:
- The contraction rate of the RV area did not differ significantly between mild and severe RCA stenosis, suggesting it's not a reliable indicator of RCA stenosis severity.
- Severe RCA stenosis was associated with a significantly decreased shortening rate of the RV free wall (14.5%) and impaired wall thickness changes, particularly evident in long-axial CT images.
- Reduced RV free wall contractility was observed in the chronic stage of ischemic heart disease, indicating RV ischemia beyond acute events.
Conclusions:
- Cardiac CT is a suitable method for evaluating RV ischemia due to RCA lesions, as it allows independent assessment of RV free wall contractility.
- Reduced RV free wall shortening rate (<20%) combined with poor changes in wall thickness on CT suggests severe RCA stenosis.
- These findings highlight the presence of RV dysfunction in chronic ischemic heart disease and the diagnostic value of CT in its assessment.
Abstract:
One hundred and eight cases with ischemic heart disease except for acute myocardial infarction were examined by cardiac computed tomography with ECG-gated scanning. The right ventricular (RV) wall contractility was evaluated by the long-axial and short-axial CT images in terms of (a) contraction rate of the RV area, (b) shortening rate of the RV free wall and (c) changes in the thickness of the RV free wall in cardiac cycle. These parameters were compared to the findings of coronary angiography and left ventriculography. 1. There was no difference of the contraction rate of the RV area between the cases with severe (90-100%) right coronary (RCA) stenosis and those with mild (0-75%) stenosis, while the contraction rate of the RV area was markedly decreased in the former combined with the impaired contraction of the ventricular septum. Consequently, it was assumed that RV function is hardly damaged by RCA lesion alone, and that the contraction rate of the RV area is not a suitable parameter for the assessment of the severity of RCA stenosis. 2. The shortening rate of the RV free wall in the long-axial image in cases with severe RCA stenosis was significantly decreased (14.5 +/- 4.6%) compared with that of mild stenosis (27.8 +/- 5.0%). The changes in the thickness of the RV free wall were also impaired in severe RCA stenosis. Same tendency was observed in the short-axial image, while the correlation between RCA stenosis and impaired contraction of the RV free wall was much more evident in the long-axis image than in the short-axis image. As the result, reduced RV contraction due to RCA ischemia seems to exist not only in acute myocardial infarction but also in chronic stage of the ischemic heart. 3. CT method is suitable for the evaluation of RV ischemia due to RCA lesion because the contractility of the RV free wall can be assessed independently of ventricular septal contraction. In cases with reduction of the free wall shortening rate under 20% combined with poor change in the thickness of the RV free wall, severe stenosis of the RCA should be suspected.