Assessment of biatrial function in clinically well pediatric bicaval heart transplantation patients by three-dimensional echocardiography.

Atrial size and function are closely correlated with atrial contributions to cardiovascular performance. Therefore, in this study, we aimed to assess atrial size and function in pediatric heart transplantation (HTx) patients using three-dimensional echocardiography (3DE). We enrolled 33 clinically well pediatric HTx patients and 33 healthy controls with a similar distribution of sex and age to the HTx patients. All patients underwent two-dimensional echocardiography (2DE) and 3DE. 2DE- and 3DE-derived biatrial maximal volume (Vmax), minimal volume (Vmin), ejection volume (EV), ejection fraction (EF), volume before atrial contraciton (VpreA), passive EV, passive EF, active EV and active EF were obtained in all patients. The 3D left atrail (LA) Vmax, Vmin and VpreA increased significantly in HTx patients after being indexed by BSA, while 3D LAEV and passive EV decreased significantly (P < 0.05). Moreover, the 3D LAEF, LA passive EF, and LA active EF all decreased significantly in HTx patients (P < 0.05). The 3D right atrial (RA) Vmax, Vmin, and VpreA increased significantly in HTx patients (P < 0.05), while the 3D RAEF and RA passive EF decreased significantly in HTx patients (P < 0.05). 3DE-derived LAVmax, LAVpreA, LA passive EV, LAEF, and LA passive EF were all lower than the corresponding 2D parameters. 3DE-derived RAVpreA, RA passive EV and RAEF were all lower than the corresponding 2D parameters. Atrial sizes and function assessed by 3DE- and 2DE-derived parameters, yield significantly discordant results in pediatric HTx patients. 3DE confirms significantly enlarged atrial sizes and decreased atrial functions in pediatric HTx patients.

Mechanophysiologically active patch for closure of atrial septal defect.

Closure of atrial septal defects (ASDs) can be achieved by various methods right from direct closure to patch closure using various materials viz. pericardium, Dacron and Teflon, to device closure using percutaneous techniques. Although percutaneous techniques are the most commonly practised method in developed countries, a subset of patients will require surgical closure. Various patch materials have been used for long, but all of them have some complications and risks associated with them. We report a case of novel technique of ASD closure done using a pedicled, vascularised and contractile right atrial wall flap.

Over Ten Years of Experience with a Modified Right Atrial Anastomosis in Orthotopic Heart Transplantation: Follow-up and Comparison with the Biatrial and Bicaval Technique.

BACKGROUND: In 1997, a modified right atrial anastomosis (cavoatrial technique) for orthotopic heart transplantation (oHTx) was first developed in our institution. The purpose of this study is to report our long-term experience with this technique compared with biatrial and bicaval technique. METHODS: Retrospectively, 202 consecutive oHTx between 1997 and 2013 were analyzed. The applied transplantation techniques were biatrial (n = 108), bicaval (n = 22), and cavoatrial (n = 72). RESULTS: Demographic data were similar in all groups. The cardiopulmonary bypass and cross-clamp time were significantly shorter in the biatrial group. Follow-up echocardiographic examination showed excellent results in all groups with no relevant differences. After 1 year, occurrence of severe tricuspid regurgitation (biatrial 1.9% vs bicaval 0.0% vs cavoatrial 1.4%) was low in all groups. Rate of permanent pacemaker implantations was also low (12.0% vs 5.0% vs 11.1%). There were no significant differences in survival between the groups. CONCLUSION: The cavoatrial technique can be a safe and simple alternative for heart transplantation. Easy handling and similar reduced postoperative complications encourage the use of this technique.

Atrial function in heart transplant recipients operated with the bicaval technique.

OBJECTIVES: In heart transplantation (HTx) with the bicaval technique the whole right atrium (RA) is donor tissue while the left atrium (LA) consists of both donor and recipient tissue. The aims of the study were to describe atrial function in comparison with healthy controls and to identify determinants of dysfunction. DESIGN: Forty-three patients and 30 controls were retrospectively included. Echocardiography was performed within 24 h of right heart catheterization (RHC) (HTx recipients). RESULTS: The peak longitudinal atrial systolic strain (ɛ) described the atrial reservoir function. The LA and RA reservoir function were reduced versus controls (LA-ɛ 18 ± 8 versus 44 ± 10%; RA-ɛ 22 ± 10 versus 69 ± 17%, p < 0.001). There were moderate relationships between atrial-ɛ and ventricular filling pressure (r = -0.64 for LA-ɛ; r = -0.57 for RA-ɛ). In a multiple regression analysis the LA-ɛ was determined by pulmonary capillary wedge pressure (PCWP) and LA minimum volume index (r = -0.71) while RA-ɛ was dependent on the right ventricular ɛ (r = -0.77). CONCLUSIONS: Atrial reservoir function is markedly reduced in HTx recipients related to elevated PCWP and LA-enlargement in the LA and in the RA impaired longitudinal right ventricular function.

Intravital microscopy to study myocardial engraftment.

Tissue engineering and stem cell transplantation are promising novel therapies for myocardial repair. A major barrier to cell survival after transplantation involves inadequate vascularization. Continuous observation of cardiac tissue engraftment and angiogenesis could help understand these processes and allow for identification of the optimal conditions for these therapeutic interventions. We investigated the ability of a skin-fold chamber model to allow for engraftment of differentiated myocardial tissue in mice. Neonatal atrial and ventricular tissues were implanted in the in vivo chambers. All myocardial implants had a high rate of engraftment (86-95%). Tissue engraftment was preceded by a 'bleeding phase' in both the atrial and ventricular implants. This occurred earlier in ventricular compared with atrial implants. Spontaneous contractions were observed after an average of 13 days after implantation in all chambers but occurred earlier in ventricular compared with atrial implants. The host cells surrounded the myocardial implants circumferentially, but have limited infiltration into these grafts. This is the first report of successful ectopic engraftment of differentiated myocardium using a skin-fold chamber. This model is invaluable for real-time observation of early angiogenesis and tissue growth during in vivo myocardial engineering and myocardial regeneration.

Total venous inflow occlusion and pericardial auto-graft reconstruction for right atrial hemangiosarcoma resection in a dog.

A sizeable right atrial hemangiosarcoma in a 6-year-old Bordeaux dog, World Health Organization (WHO) stage 2, was excised using total venous inflow occlusion. The defect was restored with a non-vascularized pericardial auto-graft. The dog had a disease-free interval of 7 mo. The dog was euthanized 9 months later, at which time there were distant metastases but no indication of local recurrence.

Occlusion totale du remplissage veineux et reconstruction par autogreffe péricardique pour une résection d'un hémangiosarcome atrial droit chez un chien. Un hémangiosarcome atrial droit considérable chez un chien Dogue de Bordeaux âgé de 6 ans, stade 2 de l'Organisation mondiale de la santé (OMS), a été excisé en utilisant l'occlusion totale du remplissage veineux. Le défaut a été rétabli par une autogreffe péricardique non vascularisée. Le chien a connu une période de sept mois sans maladie. Le chien a été euthanasié 9 mois plus tard, lorsque des métastases distantes ont été décelées, mais sans indication d'une récurrence locale.(Traduit par Isabelle Vallières).

Impact of collagen type I turnover on the long-term response to cardiac resynchronization therapy.

AIMS: We investigated whether collagen type I turnover influences the long-term response to cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Serum carboxy-terminal propeptide of procollagen type I or PICP (a marker of collagen type I synthesis) and carboxy-terminal telopeptide of collagen type I or CITP (a marker of collagen type I degradation) were measured in heart failure patients at baseline and after 1 year of CRT. Patients were categorized as responders or non-responders if they increased the distance walked in 6 min by > or <10%, respectively. At baseline, the PICP:CITP ratio, an index of the degree of coupling between collagen type I synthesis and degradation was higher (P = 0.006) in responders than in non-responders. Whereas the PICP:CITP ratio decreased (P= 0.000) after treatment in responders, it remained unchanged in non-responders. Thus, at 1-year, the PICP:CITP ratio was similar in the two groups of patients. A direct correlation (r = 0.289, P = 0.037) was found between the baseline PICP:CITP ratio and the change in the distance walked in 6 min in all patients. Receiver operating characteristics curves showed that a cut-off value of 14.4 for the PICP:CITP ratio provided 70% specificity and 63% sensitivity for the predicting response to CRT with a relative risk of 2.07 (95% confidence interval, 0.98-4.39). CONCLUSION: Collagen type I turnover influences the long-term response to CRT. In addition, the ability of CRT to restore the balance between collagen type I synthesis and degradation is associated with a beneficial response.

Biological pacemaker created by fetal cardiomyocyte transplantation.

BACKGROUND: The aim of this study was to investigate the feasibility of an alternative approach to electronic pacemaker by using spontaneously excitable cell grafts as a biological pacemaker in a large animal model of complete atrioventricular block. METHODS AND RESULTS: Dissociated male human atrial cardiomyocytes including sinus nodal cells were grafted into the free wall of the left ventricle in five female pigs. Three weeks after the injection of cell-grafted solution/control medium the pigs underwent catheter ablation of the atrioventricular node (AV-node). After complete AV block was created, the idioventricular beat rate was more rapid in cell-grafted pigs than that in control pigs (86+/-21 vs. 30+/-10 bpm; P<0.001). Administering of isoprenalin significantly increased idioventricular rate from 86+/-21 to 117+/-18 bpm in the cell-grafted animals (P<0.01). Electrophysiological mapping studies demonstrated that the idioventricular rhythm originated from the cell-injection site. Polymerase chain reaction verifying the existence of SRY DNA in the cell injection site indicated that the grafted male cells were survived. Furthermore, the connexin-43 and N-cadherin positive junctions between donor cardiomyocytes and host cells were identified. CONCLUSION: Xenografted fetal human atrial cardiomyocytes are able to survive and integrate into the host myocardium, and show a pacing function that can be modulated by autonomic agents.