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Asynchronous volume changes of the two ventricles after Fontan operation in patients with a biventricular heart
H Yamamura1, M Nakazawa, I Park
1Department of Pediatric Cardiology, Tokyo Women's Medical College, Japan.
Insights
Ventricular contraction synchrony is crucial for Fontan circulation. Greater synchrony in patients with biventricular hearts correlates with improved cardiac function and output.
Area of Science:
- Cardiology
- Pediatric Cardiology
- Congenital Heart Disease
Background:
- Fontan circulation is a palliative surgical procedure for single-ventricle congenital heart defects.
- Maintaining adequate cardiac output is essential for long-term outcomes in Fontan patients.
- Biventricular hearts undergoing Fontan operation present unique challenges in assessing pump function.
Purpose of the Study:
- To evaluate the synchronism of ventricular contraction in patients with a biventricular heart after Fontan operation.
- To determine the relationship between ventricular synchrony and cardiac function parameters.
- To assess the impact of biventricular synchrony on Fontan circulation efficiency.
Main Methods:
- Analyzed ventricular volume changes from angiograms in 11 post-Fontan patients.
- Calculated synchronous ratio (volume changes) and stroke volume ratio between ventricles.
- Correlated these ratios with cardiac index, end-diastolic volume, and ejection fraction.
Main Results:
- Patients with higher synchronous ratios (≥0.75) and stroke volume ratios (>0.95) showed better cardiac index (3.2 vs 2.4 l/min/m2) and ejection fraction (0.44 vs 0.33).
- Lower synchrony was inversely correlated with cardiac output.
- Significant differences in cardiac function parameters were observed between groups with high and low synchrony.
Conclusions:
- Ventricular contraction synchronism significantly impacts cardiac function in biventricular hearts with Fontan circulation.
- Optimizing ventricular synchrony may be a therapeutic target to improve outcomes in these patients.
- Further research is needed to explore interventions that enhance biventricular synchrony post-Fontan operation.
Abstract:
Coordinated contraction of the ventricle is an important determinant of pump function, which seems to be particularly important in Fontan circulation with one pumping ventricle. We analyzed the synchronism of contraction of the two ventricles in 11 patients with a biventricular heart who had undergone Fontan operation. Curves representing ventricular volume changes in a cardiac cycle measured on angiograms were smoothed and divided into 20 segments. We calculated the number of segments of the same directional volume changes (synchronous changes) between the two ventricles (synchronous ratio). We also calculated the total volume of the two ventricles (the two as one whole ventricle) by adding their volumes in each segment and calculated the ratio (stroke volume ratio) of the aortic stroke volume from the whole ventricle to the sum of stroke volumes of the morphological right and left ventricles. If the two ventricles ejected the blood in a completely synchronous manner, these ratios should be 1.0. In seven patients with synchronous ratios of 0.75 or greater and a stroke volume ratio of greater than 0.95, the cardiac index was 3.2 +/- 0.3 l/min/m2, the maximum total volume (corresponding to end-diastolic volume) was 106 +/- 45% normal, and the ejection fraction was 0.44 +/- 0.10. In four patients with ratios of less than 0.70 and 0.95, respectively, the parameters were 2.4 +/- 0.5 (P < 0.05), 193 +/- 92%, and 0.33 +/- 0.08, respectively. The synchronous ratio was inversely correlated with cardiac output. In conclusion, synchronism of the cardiac cycle of the two ventricles affects Fontan circulation in patients with a biventricular heart.
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