Ventricle In Tetralogy Of Fallot Research Articles

The right ventricle in tetralogy of Fallot: adaptation to sequential loading.

Right ventricular dysfunction is a major determinant of outcome in patients with complex congenital heart disease, as in tetralogy of Fallot. In these patients, right ventricular dysfunction emerges after initial pressure overload and hypoxemia, which is followed by chronic volume overload due to pulmonary regurgitation after corrective surgery. Myocardial adaptation and the transition to right ventricular failure remain poorly understood. Combining insights from clinical and experimental physiology and myocardial (tissue) data has identified a disease phenotype with important distinctions from other types of heart failure. This phenotype of the right ventricle in tetralogy of Fallot can be described as a syndrome of dysfunctional characteristics affecting both contraction and filling. These characteristics are the end result of several adaptation pathways of the cardiomyocytes, myocardial vasculature and extracellular matrix. As long as the long-term outcome of surgical correction of tetralogy of Fallot remains suboptimal, other treatment strategies need to be explored. Novel insights in failure of adaptation and the role of cardiomyocyte proliferation might provide targets for treatment of the (dysfunctional) right ventricle under stress.

An Optimistic View towards the Real Time 3D Echocardiography in Congenital Heart Disease: A Simple 'Crop Box' Should Give an Infinite Information in the Near Future!

REFER TO THE PAGE 123-127 Recent advancement of technology of medical imaging systems has enabled in-depth real time spatiotemporal diagnosis of human heart disease. It is regardless to mention that prognosis of cardiac disease is based critically on prompt 3 dimensional (3D) diagnosis of a structural anomaly, functional analysis and followed by a proper treatment. Although we are in current era of 3D skills in the spotlight, yet real time 3D echocardiography (RT3DE) is not so appealing to very busy pediatric and adult cardiologists. Mental reconstruction of harvested 2 dimensional (2D) echocardiographic images is a still much faster and simpler way to understand complex cardiac structural anomaly than doing a few more steps for subsequent data analysis with a software program of RT3DE. On the other hand, considering superiority of function of volume assessment, RT3DE can be very useful in clinical application as it can provide numeric data more precisely than morphologic visual assessment of each cardiac chambers that enables assessment longitudinally during the clinical course. In congenital heart disease (CHD), volume or pressure overloaded condition frequently results in distortion of septal planes followed by a geometric change in either ventricles that hampers precise ventricular volume assessment using conventional 2D echocardiography.1),2) There are many reports on the reproducibility of RT3DE in clinical application to adults population without a complex heart disease.3) It is known that current RT3DE has relatively a high intraobserver and interobserver variability.4) In pediatric cases with a complex CHD, additional time consuming effort is required for the assessment of detailed anatomical defect during navigation of intriguing small cardiac structures to acquire optimal planes for secondary 3D reconstruction. Novel imaging tools including RT3DE always require its validation steps. Many studies on the left ventricular volume and ejection fraction compared to cardiac magnetic resonance imaging (MRI) data, currently a gold standard method of cardiac volume assessment have been published during the last ten years.5),6) It is known that the results acquired by RT3DE of left ventricular volume assessment has strong correlation with cardiac MRI although ventricular volume by RT3DE has tendency of underestimation.6),7),8) Studying with cardiac MRI in pediatric patients in critical condition with CHD has several limitations as to its long scanning time and practical issues on patient's sedation and infeasibility in patients with pacemaker. If we mention about volumetric assessment of right ventricle considering its 3 dimensionally distorted morphology compared to left ventricle, there should be no doubt on the superiority of RT3DE to 2D echocardiography and related issues are published.9),10) As RT3DE is a noninvasive method, if it can overcome current several issues of its limitation, it might be the most useful tool to examine children with CHD. Many experts in the field of echocardiography believe that its clinical application by skillful clinicians will provide infinite derivative outcomes in longitudinal monitoring of functional abnormality especially in cases with surgically corrected complex CHD.11),12) However in reality, likewise cardiac MRI, RT3DE is still a secondary option to conventional 2D echocardiography with its limitations and infeasibility to pediatric populations with CHD. Therefore, further studies on this issue are strongly encouraged for further analysis. An inspiring outcome shown here titled 'Assessment of left ventricular volume and function using real-time 3D echocardiography versus angiocardiography in children with Tetralogy of Fallot' is that RT3DE can be practically and convincingly used in volumetric assessment in CHD patients with real time and non-invasive scanning.13) Authors tried to validate RT3DE comparing with angiographic data. Considering hard working in assessment of complicated geometric deformation of left ventricle in tetralogy of Fallot and technical difficulty in handling pediatric patients, this study is deserved the spotlight. They showed that there was a strong correlation between the mean value of the left ventricular end diastolic volume and its index measured by RT3DE and angiography with good intra- and inter-observer reliability. With training time and experience, unquestionably a simple 'crop box' will give us an infinitely useful information with simplified off-line analysis of harvested images with a cutting-edge software program. With an optimistic view towards the RT3DE in CHD, current doubt on values of RT3DE hopefully should be faded with an accelerated speed with the help of advancement of technology in the near future.

Evaluation of knowledge-based reconstruction for magnetic resonance volumetry of the right ventricle in tetralogy of Fallot.

Cardiac magnetic resonance using the Simpson method is the gold standard for right ventricular volumetry. However, this method is time-consuming and not without sources of error. Knowledge-based reconstruction is a novel post-processing approach that reconstructs the right ventricular endocardial shape based on anatomical landmarks and a database of various right ventricular configurations. To assess the feasibility, accuracy and labor intensity of knowledge-based reconstruction in repaired tetralogy of Fallot (TOF). The short-axis cine cardiac MR datasets of 35 children and young adults (mean age 14.4 ± 2.5years) after TOF repair were studied using both knowledge-based reconstruction and the Simpson method. Intraobserver, interobserver and inter-method variability were assessed using Bland-Altman analyses. Knowledge-based reconstruction was feasible and highly accurate as compared to the Simpson method. Intra- and inter-method variability for knowledge-based reconstruction measurements showed good agreement. Volumetric assessment using knowledge-based reconstruction was faster when compared with the Simpson method (10.9 ± 2.0 vs. 7.1 ± 2.4min, P < 0.001). In patients with repaired tetralogy of Fallot, knowledge-based reconstruction is a feasible, accurate and reproducible method for measuring right ventricular volumes and ejection fraction. The post-processing time of right ventricular volumetry using knowledge-based reconstruction was significantly shorter when compared with the routine Simpson method.

Evaluation of knowledge-based reconstruction for magnetic resonance volumetry of the right ventricle in tetralogy of fallot

Cardiac magnetic resonance using the Simpson method is the gold standard for right ventricular volumetry. However, this method is time-consuming and not without sources of error. Knowledge-based reconstruction is a novel post-processing approach that reconstructs the right ventricular endocardial shape based on anatomical landmarks and a database of various right ventricular configurations. To assess the feasibility, accuracy and labor intensity of knowledge-based reconstruction in repaired tetralogy of Fallot (TOF). The short-axis cine cardiac MR datasets of 35 children and young adults (mean age 14.4 ± 2.5 years) after TOF repair were studied using both knowledge-based reconstruction and the Simpson method. Intraobserver, interobserver and inter-method variability were assessed using Bland-Altman analyses. Knowledge-based reconstruction was feasible and highly accurate as compared to the Simpson method. Intra- and inter-method variability for knowledge-based reconstruction measurements showed good agreement. Volumetric assessment using knowledge-based reconstruction was faster when compared with the Simpson method (10.9 ± 2.0 vs. 7.1 ± 2.4 min, P < 0.001). In patients with repaired tetralogy of Fallot, knowledge-based reconstruction is a feasible, accurate and reproducible method for measuring right ventricular volumes and ejection fraction. The post-processing time of right ventricular volumetry using knowledge-based reconstruction was significantly shorter when compared with the routine Simpson method.

Fractional gradients along the outflow tract of the right ventricle in tetralogy of Fallot: Anatomic and hemodynamic correlative study

In 16 patients undergoing surgical correction of tetralogy of Fallot, attempts were made to determine where, in the outflow tract, the most critical preoperative obstruction was located. In the open chest, pressures were taken in the right ventricle, proximal conus, distal conus, and pulmonary artery. Pressure gradients between these levels were indicative of stenosis at the infundibular ostium (Ost.), conus (C), and pulmonary valve (PV), respectively. Total delta P = delta P Ost. + delta P C + delta P PV, where delta P is the pressure gradient between the right ventricle and the pulmonary artery. In order to evaluate the contribution of each obstructive segment to the overall obstruction, we introduced a new term, the fractional gradient (FG). The FG is defined by the following formula: FG = (delta P segmental/delta P total). The average total pressure gradient in this series was 7 mm Hg. The average segmental gradients were 15.5, 39.0, and 17.0 mm Hg for the infundibular ostium, conus, and pulmonary valve, respectively. The FGs across segments were 0.20, 0.54, and 0.26, indicating that only 20% of the average obstruction was located in the infundibular ostium. The remaining obstruction is distal and unrelated to the infundibular ostium. Analysis of the FGs in the various types of conus indicated, from an anatomic viewpoint, that in 80% of patients with tetralogy the infundibulectomy does not have to be radical.

Left Ventricular Myocardial Infarction in Tetralogy of Fallot

Myocardial infarction (MI) is relatively infrequent in infants and children, although its association with anomalous origin of the left coronary artery and other congenital cardiac anomalies that result in coronary hypoperfusion is well known. 1 Although MI has also been reported in some congenital heart defects without coronary artery abnormalities, 2-4 massive MI of the left ventricle in tetralogy of Fallot (TOF) has not, to our knowledge, been reported. Report of a Case. —An 8-month-old girl had been followed up elsewhere with the clinical diagnosis of TOF. Although moderately cyanotic, she had no history of hypoxic spells. On the morning of admission, she had an hypoxic spell. Because of poor response to conventional therapy, ie, knee-chest position, sodium bicarbonate, and morphine, she was transferred to our institution. On arrival, she was cool and blue-gray; heart rate was 150 beats per minute; respirations, 80/min; and blood pressure, 60/40 mm Hg. There

Surgical anatomy of obstructing muscle bands of the right ventricle in tetralogy of Fallot

Surgical anatomy of obstructing muscle bands of the right ventricle in tetralogy of Fallot

Volume of the left ventricle in tetralogy of Fallot

Left ventricular volumes were measured by the angiocardiographic technic in 25 patients with tetralogy of Fallot, of whom 6 had a Potts or Blalock-Taussig anastomotic operation and 5 had complete repair of the defect. In 12 of the 14 patients who underwent no surgical procedure, the left ventricular volume was in the low normal range; the 2 others (with severe forms of tetralogy of Fallot) had significantly reduced end-diastolic volumes. In patients who had an anastomotic operation, the ventricular volumes were considerably increased if the left to right flow was large enough to cause symptoms; in the others they were in the normal range. Approximately two weeks after complete repair, the mean left ventricular volume was less than that for patients not operated upon. Significant aorticopulmonary collateral flow and some flow directly from the right to the left ventricle contribute to the normal volumes of the left ventricle in tetralogy of Fallot. Left ventricular myocardial function (as evidenced by ejection fraction) is significantly better after complete repair than it is in patients not operated upon or in patients treated by an anastomotic operation.