Pulse wave signal-driven machine learning for identifying left ventricular enlargement in heart failure patients.

BACKGROUND: Left ventricular enlargement (LVE) is a common manifestation of cardiac remodeling that is closely associated with cardiac dysfunction, heart failure (HF), and arrhythmias. This study aimed to propose a machine learning (ML)-based strategy to identify LVE in HF patients by means of pulse wave signals. METHOD: We constructed two high-quality pulse wave datasets comprising a non-LVE group and an LVE group based on the 264 HF patients. Fourier series calculations were employed to determine if significant frequency differences existed between the two datasets, thereby ensuring their validity. Then, the ML-based identification was undertaken by means of classification and regression models: a weighted random forest model was employed for binary classification of the datasets, and a densely connected convolutional network was utilized to directly estimate the left ventricular diastolic diameter index (LVDdI) through regression. Finally, the accuracy of the two models was validated by comparing their results with clinical measurements, using accuracy and the area under the receiver operating characteristic curve (AUC-ROC) to assess their capability for identifying LVE patients. RESULTS: The classification model exhibited superior performance with an accuracy of 0.91 and an AUC-ROC of 0.93. The regression model achieved an accuracy of 0.88 and an AUC-ROC of 0.89, indicating that both models can quickly and accurately identify LVE in HF patients. CONCLUSION: The proposed ML methods are verified to achieve effective classification and regression with good performance for identifying LVE in HF patients based on pulse wave signals. This study thus demonstrates the feasibility and potential of the ML-based strategy for clinical practice while offering an effective and robust tool for diagnosing and intervening ventricular remodeling.

Machine learning predicts blood lactate levels in children after cardiac surgery in paediatric ICU.

BACKGROUND: Although serum lactate levels are widely accepted markers of haemodynamic instability, an alternative method to evaluate haemodynamic stability/instability continuously and non-invasively may assist in improving the standard of patient care. We hypothesise that blood lactate in paediatric ICU patients can be predicted using machine learning applied to arterial waveforms and perioperative characteristics. METHODS: Forty-eight post-operative children, median age 4 months (2.9-11.8 interquartile range), mean baseline heart rate of 131 beats per minute (range 33-197), mean lactate level at admission of 22.3 mg/dL (range 6.3-71.1), were included. Morphological arterial waveform characteristics were acquired and analysed. Predicting lactate levels was accomplished using regression-based supervised learning algorithms, evaluated with hold-out cross-validation, including, basing prediction on the currently acquired physiological measurements along with those acquired at admission, as well as adding the most recent lactate measurement and the time since that measurement as prediction parameters. Algorithms were assessed with mean absolute error, the average of the absolute differences between actual and predicted lactate concentrations. Low values represent superior model performance. RESULTS: The best performing algorithm was the tuned random forest, which yielded a mean absolute error of 3.38 mg/dL when predicting blood lactate with updated ground truth from the most recent blood draw. CONCLUSIONS: The random forest is capable of predicting serum lactate levels by analysing perioperative variables, including the arterial pressure waveform. Thus, machine learning can predict patient blood lactate levels, a proxy for haemodynamic instability, non-invasively, continuously and with accuracy that may demonstrate clinical utility.

Partial anomalous pulmonary venous drainage repair concomitant with bilateral semilunar valve replacements and pulmonary artery reconstruction for an adult female 20 years after initial truncus arteriosus repair.

We describe the case of a 21-year-old patient who underwent repairs for multiple lesions including aortic and pulmonary valve replacements, right ventricular outflow tract reconstruction, revision of the right pulmonary artery route, and a repair of partial anomalous pulmonary venous drainage, which was diagnosed during this fourth sternotomy. For these patients with adult CHD, it is most important to address all underlying factors as much as possible at the redo surgery.

Daily transient discontinuation of extracorporeal LVAD to prevent thromboembolism of mechanical aortic valve prosthesis.

Patients with mechanical aortic valves are generally contraindicated for left ventricular assist device (LVAD) insertion because the prosthetic valve often becomes fixed in closed position. A 41-year-old woman with mechanical aortic valve prosthesis experienced sudden chest pain and developed cardiogenic shock. A paracorporeal pulsatile LVAD and a monopivot centrifugal pump as a right VAD (RVAD) were implanted. The mechanical aortic valve was intentionally left in place. Soon after the operation, LVAD support was discontinued daily for few seconds to allow the mechanical aortic valve to open and to avoid thrombus formation. The patient was successfully weaned off RVAD and received anticoagulation therapy with warfarin. On postoperative day 141, she was transferred to a university hospital where a HeartMate II LVAD was implanted, and the aortic valve was successfully replaced with a bioprosthetic valve. The patient is currently awaiting heart transplantation.

Factors associated with a low initial cerebral oxygen saturation value in patients undergoing cardiac surgery.

Regional cerebral oximetry using near-infrared spectroscopy device, an INVOS 5100 C (Medtronic, Minneapolis, MN, USA), during cardiac surgery aims to avoid perioperative neurological impairment, especially during cardiopulmonary bypass. However, it is not uncommon to encounter critically low initial cerebral regional oxygen saturation or a low value unresponsive to intervention. Therefore, it is important to identify factors associated with low saturation value other than true cerebral hypoxia. We investigated the relationship between preoperative regional cerebral oxygen saturation and clinical variables during cardiac surgery. From January 2013 to May 2016, 462 patients underwent elective cardiac surgery. Patient's ≤12 years of age, with acute cerebral infarction, with previous intracranial hemorrhage or neurosurgery, with concomitant aortic surgery, and having off-pump coronary artery bypass surgery were excluded. The remaining 223 patients were monitored by intraoperative regional cerebral oximetry. Univariate analysis found that scalp-cortex distance, cerebrospinal fluid thickness, left ventricular ejection fraction, hemoglobin concentration, estimated glomerular filtration rate, and hemodialysis were significantly correlated with the initial regional oxygen saturation value. Multiple regression analysis revealed that scalp-cortex distance, left ventricular ejection fraction, hemoglobin, and hemodialysis remained as significant variables. A receiver operating characteristic analysis found that for a low initial regional oxygen saturation value of 40%, the thresholds of scalp-cortex distance, left ventricular ejection fraction, and hemoglobin concentration were 17.6 mm, 45.2%, and 7.5 g/dl, respectively. In conclusion, brain atrophy, poor left ventricular function, anemia, and hemodialysis were associated with low initial cerebral regional oxygen saturation values in adult cardiac surgery patients.

Impact of the location of the fenestration on Fontan circulation haemodynamics: a three-dimensional, computational model study.

OBJECTIVES: There is no consensus or theoretical explanation regarding the optimal location for the fenestration during the Fontan operation. We investigated the impact of the location of the fenestration on Fontan haemodynamics using a three-dimensional Fontan model in various physiological conditions. METHODS: A three-dimensional Fontan model was constructed on the basis of CT images, and a 4-mm-diameter fenestration was located between the extracardiac Fontan conduit and the right atrium at three positions: superior, middle, and inferior part of the conduit. Haemodynamics in the Fontan route were analysed using a three-dimensional computational fluid dynamic model in realistic physiological conditions, which were predicted using a lumped parameter model of the cardiovascular system. The respiratory effect of the caval flow was taken into account. The flow rate through the fenestration, the effect of lowering the central venous pressure, and wall shear stress in the Fontan circuit were evaluated under central venous pressures of 10, 15, and 20 mmHg. The pulse power index and pulsatile energy loss index were calculated as energy loss indices. RESULTS: Under all central venous pressures, the middle-part fenestration demonstrated the most significant effect on enhancing the flow rate through the fenestration while lowering the central venous pressure. The middle-part fenestration produced the highest time-averaged wall shear stress, pressure pulse index, and pulsatile energy loss index. CONCLUSIONS: Despite slightly elevated energy loss, the middle-part fenestration most significantly increased cardiac output and lowered central venous pressure under respiration in the Fontan circulation.

[Perioperative Management of Fontan Operation].

Surgical results of Fontan operation has been improved over the decades due to the introduction of the staged operations and some modifications of Fontan route from the classical atrio-pulmonary connection to total cavo-pulmonary connection. However, issues remain because of the single ventricular physiology of Fontan circulation. This article explains about the preoperative checklist for Fontan operation and tips on the postoperative management including an early extubation, use of inhaled nitric oxide after extubation, anticoagulation therapy, and efficacy of angiotensin converting enzyme inhibitor, supported by the cutting-edge evidence. Some patients who underwent Fontan operation, however, suffer from protein-losing enteropathy, heart failure, and thus are classified as failing Fontan. Treatment for these patients with failed Fontan is an unsolved problem in the state where heart transplantation is inadequately available in Japan.

Influence of Cardiac Function and Loading Conditions on the Myocardial Performance Index - Theoretical Analysis Based on a Mathematical Model.

BACKGROUND: The myocardial performance index (MPI) has emerged as a Doppler-derived index for global ventricular function capable of estimating combined systolic and diastolic performance. While several studies have reported its load-dependency, responses of the MPI to various hemodynamic changes have not been fully characterized. METHODS AND RESULTS: The response characteristics of the MPI were examined and compared with ejection fractions (EF) by changing hemodynamic parameters within the physiological range in a lumped parameter model of the cardiovascular system. At baseline, the MPI was 0.42 and the EF was 0.68. Heart rate increase resulted in a decrease in EF and an increase in the MPI. Reduction in end-systolic elastance decreased EF and increased the MPI. Volume overload and ventricular stiffening did not affect EF but paradoxically reduced the MPI. Increased afterload due to higher systemic resistance resulted in a decrease in EF and increase in the MPI, but afterload increase caused by reduced arterial compliance led to a decrease in both EF and MPI. These MPI characteristics caused paradoxical improvement of the MPI during disease progression of chronic heart failure in a simulation of mitral regurgitation. CONCLUSIONS: The MPI is affected by a wider variety of hemodynamic parameters than EF. In addition, it is predicted to decrease paradoxically with volume overload, reduction in arterial compliance, or ventricular diastolic stiffening. These MPI characteristics should be considered when assessing cardiovascular dynamics using this index.

Effects of arterial blood flow on walls of the abdominal aorta: distributions of wall shear stress and oscillatory shear index determined by phase-contrast magnetic resonance imaging.

Although abdominal aortic aneurysms (AAAs) occur mostly inferior to the renal artery, the mechanism of the development of AAA in relation to its specific location is not yet clearly understood. The objective of this study was to evaluate the hypothesis that even healthy volunteers may manifest specific flow characteristics of blood flow and alter wall shear or oscillatory shear stress in the areas where AAAs commonly develop. Eight healthy male volunteers were enrolled in this prospective study, aged from 24 to 27. Phase-contrast magnetic resonance imaging (MRI) was performed with electrocardiographic triggering. Flow-sensitive four-dimensional MR imaging of the abdominal aorta, with three-directional velocity encoding, including simple morphological image acquisition, was performed. Information on specific locations on the aortic wall was applied to the flow encodes to calculate wall shear stress (WSS) and oscillatory shear index (OSI). While time-framed WSS showed the highest peak of 1.14 ± 0.25 Pa in the juxtaposition of the renal artery, the WSS plateaued to 0.61 Pa at the anterior wall of the abdominal aorta. The OSI peaked distal to the renal arteries at the posterior wall of the abdominal aorta of 0.249 ± 0.148, and was constantly elevated in the whole abdominal aorta at more than 0.14. All subjects were found to have elevated OSI in regions where AAAs commonly occur. These findings indicate that areas of constant peaked oscillatory shear stress in the infra-renal aorta may be one of the factors that lead to morphological changes over time, even in healthy individuals.

Total Cavopulmonary Connection is Superior to Atriopulmonary Connection Fontan in Preventing Thrombus Formation: Computer Simulation of Flow-Related Blood Coagulation.

The classical Fontan route, namely the atriopulmonary connection (APC), continues to be associated with a risk of thrombus formation in the atrium. A conversion to a total cavopulmonary connection (TCPC) from the APC can ameliorate hemodynamics for the failed Fontan; however, the impact of these surgical operations on thrombus formation remains elusive. This study elucidates the underlying mechanism of thrombus formation in the Fontan route by using a two-dimensional computer hemodynamic simulation based on a simple blood coagulation rule. Hemodynamics in the Fontan route was simulated with Navier-Stokes equations. The blood coagulation and the hemodynamics were combined using a particle method. Three models were created: APC with a square atrium, APC with a round atrium, and TCPC. To examine the effects of the venous blood flow velocity, the velocity at rest and during exercise (0.5 and 1.0 W/kg) was measured. The total area of the thrombi increased over time. The APC square model showed the highest incidence for thrombus formation, followed by the APC round, whereas no thrombus was formed in the TCPC model. Slower blood flow at rest was associated with a higher incidence of thrombus formation. The TCPC was superior to the classical APC in terms of preventing thrombus formation, due to significant blood flow stagnation in the atrium of the APC. Thus, local hemodynamic behavior associated with the complex channel geometry plays a major role in thrombus formation in the Fontan route.

Hemodynamic performance of the Fontan circulation compared with a normal biventricular circulation: a computational model study.

The physiological limitations of the Fontan circulation have been extensively addressed in the literature. Many studies emphasized the importance of pulmonary vascular resistance in determining cardiac output (CO) but gave little attention to other cardiovascular properties that may play considerable roles as well. The present study was aimed to systemically investigate the effects of various cardiovascular properties on clinically relevant hemodynamic variables (e.g., CO and central venous pressure). To this aim, a computational modeling method was employed. The constructed models provided a useful tool for quantifying the hemodynamic effects of any cardiovascular property of interest by varying the corresponding model parameters in model-based simulations. Herein, the Fontan circulation was studied compared with a normal biventricular circulation so as to highlight the unique characteristics of the Fontan circulation. Based on a series of numerical experiments, it was found that 1) pulmonary vascular resistance, ventricular diastolic function, and systemic vascular compliance play a major role, while heart rate, ventricular contractility, and systemic vascular resistance play a secondary role in the regulation of CO in the Fontan circulation; 2) CO is nonlinearly related to any single cardiovascular property, with their relationship being simultaneously influenced by other cardiovascular properties; and 3) the stability of central venous pressure is significantly reduced in the Fontan circulation. The findings suggest that the hemodynamic performance of the Fontan circulation is codetermined by various cardiovascular properties and hence a full understanding of patient-specific cardiovascular conditions is necessary to optimize the treatment of Fontan patients.

Blood flow dynamic improvement with aneurysm repair detected by a patient-specific model of multiple aortic aneurysms.

Aortic aneurysms may cause the turbulence of blood flow and result in the energy loss of the blood flow, while grafting of the dilated aorta may ameliorate these hemodynamic disturbances, contributing to the alleviation of the energy efficiency of blood flow delivery. However, evaluating of the energy efficiency of blood flow in an aortic aneurysm has been technically difficult to estimate and not comprehensively understood yet. We devised a multiscale computational biomechanical model, introducing novel flow indices, to investigate a single male patient with multiple aortic aneurysms. Preoperative levels of wall shear stress and oscillatory shear index (OSI) were elevated but declined after staged grafting procedures: OSI decreased from 0.280 to 0.257 (first operation) and 0.221 (second operation). Graftings may strategically counter the loss of efficient blood delivery to improve hemodynamics of the aorta. The energy efficiency of blood flow also improved postoperatively. Novel indices of pulsatile pressure index (PPI) and pulsatile energy loss index (PELI) were evaluated to characterize and quantify energy loss of pulsatile blood flow. Mean PPI decreased from 0.445 to 0.423 (first operation) and 0.359 (second operation), respectively; while the preoperative PELI of 0.986 dropped to 0.820 and 0.831. Graftings contributed not only to ameliorate wall shear stress or oscillatory shear index but also to improve efficient blood flow. This patient-specific modeling will help in analyzing the mechanism of aortic aneurysm formation and may play an important role in quantifying the energy efficiency or loss in blood delivery.

Fontan completions over 10 years after Glenn procedures.

OBJECTIVE: Despite the broadened indications for Fontan procedure, there are patients who could not proceed to Fontan procedure because of the strict Fontan criteria during the early period. Some patients suffer from post-Glenn complications such as hypoxia, arrhythmia, or fatigue with exertion long after the Glenn procedure. We explored the possibility of Fontan completion for those patients. METHODS: Between 2004 and 2010, five consecutive patients aged between 13 and 31 years (median 21) underwent Fontan completion. These patients had been followed up for more than 10 years (10 to 13, median 11) after Glenn procedure as non-Fontan candidates. We summarise these patients retrospectively in terms of their pre-operative physiological condition, surgical strategy, and problems that these patients hold. RESULTS: Pre-operative catheterisation showed pulmonary vascular resistance ranging from 0.9 to 3.7 (median 2.2), pulmonary to systemic flow ratio of 0.3 to 1.6 (median 0.9), and two patients had significant aortopulmonary collaterals. Extracardiac total cavopulmonary connections were performed in three patients, lateral tunnel total cavopulmonary connection in one patient, and intracardiac total cavopulmonary connection in one patient, without a surgical fenestration. Concomitant surgeries were required including valve surgeries--atrioventricular valve plasty in three patients and tricuspid valve replacement in one patient; systemic outflow tract obstruction release--Damus-Kaye-Stansel procedure in two patients and subaortic stenosis resection in one patient; and anti-arrhythmic therapies--maze procedure in two patients, cryoablation in two patients, and pacemaker implantation in two patients. All patients are now in New York Heart Association category I. CONCLUSION: Patients often suffer from post-Glenn complications. Of those, if they are re-examined carefully, some may have a chance to undergo Fontan completion and benefit from it. Multiple lesions such as atrioventricular valve regurgitation, systemic outflow obstruction, or arrhythmia should be surgically repaired concomitantly.

Transient hemodynamic changes upon changing a BCPA into a TCPC in staged Fontan operation: a computational model study.

The clinical benefits of the Fontan operation in treating single-ventricle defects have been well documented. However, perioperative mortality or morbidity remains a critical problem. The purpose of the present study was to identify the cardiovascular factors that dominate the transient hemodynamic changes upon the change of a bidirectional cavopulmonary (Glenn) anastomosis (BCPA) into a total cavopulmonary connection (TCPC). For this purpose, two computational models were constructed to represent, respectively, a single-ventricle circulation with a BCPA and that with a TCPC. A series of model-based simulations were carried out to quantify the perioperative hemodynamic changes under various cardiovascular conditions. Obtained results indicated that the presence of a low pulmonary vascular resistance and/or a low lower-body vascular resistance is beneficial to the increase in transpulmonary flow upon the BCPA to TCPC change. Moreover, it was found that ventricular diastolic dysfunction and mitral valve regurgitation, despite being well-known risk factors for poor postoperative outcomes, do not cause a considerable perioperative reduction in transpulmonary flow. The findings may help physicians to assess the perioperative risk of the TCPC surgery based on preoperative measurement of cardiovascular function.

Impacts of respiratory fluctuations on cerebral circulation: a machine-learning-integrated 0-1D multiscale hemodynamic model.

Objective. This study aims to accurately identify the effects of respiration on the hemodynamics of the human cardiovascular system, especially the cerebral circulation.Approach: we have developed a machine learning (ML)-integrated zero-one-dimensional (0-1D) multiscale hemodynamic model combining a lumped-parameter 0D model for the peripheral vascular bed and a one-dimensional (1D) hemodynamic model for the vascular network.In vivomeasurement data of 21 patients were retrieved and partitioned into 8000 data samples in which respiratory fluctuation (RF) of intrathoracic pressure (ITP) was fitted by the Fourier series. ML-based classification and regression algorithms were used to examine the influencing factors and variation trends of the key parameters in the ITP equations and the mean arterial pressure. These parameters were employed as the initial conditions of the 0-1D model to calculate the radial artery blood pressure and the vertebral artery blood flow volume (VAFV).Main results: during stable spontaneous respiration, the VAFV can be augmented at the inhalation endpoints by approximately 0.1 ml s-1for infants and 0.5 ml s-1for adolescents or adults, compared to those without RF effects. It is verified that deep respiration can further increase the ranges up to 0.25 ml s-1and 1 ml s-1, respectively.Significance. This study reveals that reasonable adjustment of respiratory patterns, i.e. in deep breathing, enhances the VAFV and promotes cerebral circulation.

Impact of Atrial Fibrillation on Fontan Circulation: Fontan Computational Model.

BACKGROUND: Patients with Fontan circulation may have heart failure resulting in atrial fibrillation during the late phase. Inotropic effects to ameliorate hemodynamics on the Fontan circulation are not well understood, especially when in atrial fibrillation. This study was performed to determine whether dobutamine therapy in patients with Fontan circulation has limited effects on improving hemodynamics. METHODS: Lumped computational models (sinus and atrial fibrillation) were used, including biventricular, atriopulmonary connection, and extracardiac total cavopulmonary connection Fontan models. The condition of atrial fibrillation including lack of atrial beat, irregular ventricular contraction, and time-varying elastance for the ventricle was introduced. A different dose of dobutamine was given by varying the elastance of the ventricle, heart rate, and peripheral resistance. RESULTS: In all models, the cardiac output decreased by 22.5% to 25.8% in atrial fibrillation. At 10 µg · kg-1 · min-1 dobutamine in sinus rhythm, the cardiac output increased by 32.3% in the biventricular model but by only 9.2% (P < .001) and 9.1% (P < .001) in the atriopulmonary connection and total cavopulmonary connection Fontan models, respectively. At 10 µg · kg-1 · min-1 dobutamine in atrial fibrillation, the percent increase in the cardiac output in the Fontan circulation (11.8% increase in atriopulmonary connection, P < .001; and 11.9% increase in total cavopulmonary connection, P < .001) was significantly less than that in the biventricular circulation (32.3% increase). CONCLUSIONS: In the Fontan circulation, atrial fibrillation itself reduced the cardiac output by approximately 25%, and dobutamine had a limited effect on increasing the cardiac output, especially when in atrial fibrillation. Maintaining sinus rhythm in patients with Fontan circulation is very important.

Paracorporeal Support in Pediatric Patients: The Role of the Patient-Device Interaction.

BACKGROUND: Ventricular assist devices are important in the treatment of pediatric heart failure. Although paracorporeal pulsatile (PP) devices have historically been used, there has been increased use of paracorporeal continuous (PC) devices. We sought to compare the outcomes of children supported with a PP or PC, or combination of devices. METHODS: A retrospective review (2005 to 2019) was made of patients less than 19 years of age from a single center who received a PC, PP, or combination of devices. Patient characteristics were compared between device strategies, and Kaplan-Meier survival analysis was performed. RESULTS: Sixty-six patients were included: 62% male; 62% non-congenital heart disease; median age 0.9 years (interquartile range, 0.2 to 4.9); and median weight 8.5 kg (interquartile range, 4.3 to 17.7 kg). The PC devices were used in 45% of patients, PP in 35%, and a combination in 20%. Patients on PC devices had a lower median weight (P = .02) and a higher proportion of congenital heart disease (P = .02), and more patients required pre-ventricular assist device dialysis (P = .01). There was no difference in pre-ventricular assist device extracorporeal membrane oxygenation use (P = .15). There was a difference in survival among the three device strategies (P = .02). CONCLUSIONS: Differences in survival were evident, with patients on PC support having worse outcomes. Transition from PC to a PP devices was associated with a survival advantage. These findings may be driven by differences in patient characteristics across device strategies. Further studies are required to confirm these findings and to better understand the interaction between patient characteristics and device options.

Coarctation of the aorta with total anomalous pulmonary venous connection: a case report.

Total anomalous pulmonary venous connection (TAPVC) and coarctation of the aorta (CoA) rarely occur together. In affected patients, blood is supplied to the lower body by saturated ductal flow. Preoperative echocardiography may not show an acceleration of flow at the isthmus (coarctation), and the oxygen saturation (SpO2) at the feet may be satisfactory. Consequently, the severity of CoA is often underestimated before performing surgery. A 6-day-old boy weighing 2.6 kg with a diagnosis of supracardiac TAPVC was referred for surgical correction of his anomaly. The atrial septal defect (ASD) was 6.7 mm in diameter. There was a large patent ductus arteriosus (PDA) without flow acceleration at the preductal entry into the descending aorta. Only the TAPVC repair was planned, but immediately following ligation of the large PDA, the blood pressure in the lower extremity dropped to around 30 mmHg. The ligation was removed. The reason for the blood pressure discrepancy between the upper and the lower body was not clear as there was no arterial line in the upper extremity and a 6.7-mm-diameter ASD can support sufficient blood flow to the lower body without the PDA. A suspected CoA was found and repaired, followed by the TAPVC repair. Caution is necessary when repairing a TAPVC and coexisting large PDA as the severity of the CoA can easily be underestimated due to nonsignificant flow acceleration.

Annular excursion contributes to efficient cardiac output: a three-dimensional echocardiographic approach.

BACKGROUND AND AIM OF THE STUDY: The heart produces an efficient cardiac output by repeating diastole and systole. With the evolution of three-dimensional (3D) echocardiography, it is possible to evaluate cardiac motion using detailed 3D morphologic echocardiography. The study aim was to evaluate mitral and aortic annulus excursions towards the apex of the left ventricle, using 3D echocardiography. Measurements of the angle variation between the mitral and aortic valve throughout the cardiac cycle were performed to determine the effects of annulus excursion on cardiac function. METHODS: Seven healthy adolescents (five males, two females; mean age 15.9 +/- 1.1 years; Group H) and seven patients with dilated cardiomyopathy (seven males; mean age 63.6 +/- 12.9 years; Group D) were selected. All subjects underwent 3D echocardiography between November 2007 and June 2008. Annulus excursion (AE) was defined as the annular motion towards the apex. The Ex-Ratio A (%) and Ex-Ratio M (%) were defined as the ratios of aortic or mitral excursion, respectively, to the maximal distance from the annulus to the left ventricular apex. The annulus was defined simply as a flat round disc, and the annular area calculated as the annular distance between the anterior and posterior annulus as a circle diameter. The annulus excursion volume (AEV) was calculated by multiplying the annular area by AE, and determined for each valve of each patient. The total AEV was the summation of the mitral and aortic AEVs. The ratio of AEV to left ventricular diastolic volume was expressed as AEV/EDV. Angular variation between the valves was measured during the cardiac cycle with the following values: maximal angle (Dmax), minimal angle (Dmin), and the difference between Dmax and Dmin (Dmax-min). RESULTS: In all cases, the apex was in a fixed position. The AE was significantly greater for group H than for group D. While AEV did not differ between groups, AEV/EDV(A) and AEV/EDV(M) were greater for group H than for group D. The angle between the mitral and aortic annulus changed throughout the cardiac cycle. The Dmax-min value was significantly greater for group H than for group D. CONCLUSION: Annulus excursion contributes to an efficient cardiac output. The angle variation was measured during the cardiac cycle and found to be greater in healthy adolescents. 3D echocardiography represents a useful modality for clarifying 'motional cardiac morphology'.

Creation of an intraatrial tunnel to produce a total cavo-pulmonary connection in a patient with dominant right ventricle, totally anomalous pulmonary venous connection, and pulmonary atresia with non-confluent pulmonary arteries.

The surgical strategy for patients having a functionally single ventricle associated with totally anomalous pulmonary venous connection and pulmonary atresia with non-confluent pulmonary artery has yet to be agreed. We created an intraatrial tunnel to produce a total cavo-pulmonary connection in such a patient, also creating a confluence for the pulmonary arteries. By minimizing the use of the GoreTex patch, the patient was able to discontinue the use of warfarin.