Haemodynamic consequences of targeted single- and dual-site right ventricular pacing in adults with congenital heart disease undergoing surgical pulmonary valve replacement

Aims The purpose of this study was to create an epicardial electroanatomic map of the right ventricle (RV) and then apply post-operative-targeted single- and dual-site RV temporary pacing with measurement of haemodynamic parameters. Cardiac resynchronization therapy is an established treatment for symptomatic left ventricular (LV) dysfunction. In congenital heart disease, RV dysfunction is a common cause of morbidity—little is known regarding the potential benefits of CRT in this setting. Methods and results Sixteen adults (age = 32 ± 8 years; 6 M, 10 F) with right bundle branch block (RBBB) and repaired tetralogy of Fallot (n = 8) or corrected congenital pulmonary stenosis (n = 8) undergoing surgical pulmonary valve replacement (PVR) for pulmonary regurgitation underwent epicardial RV mapping and haemodynamic assessment of random pacing configurations including the site of latest RV activation. The pre-operative pulmonary regurgitant fraction was 49 ± 10%; mean LV end-diastolic volume (EDV) 85 ± 19 mL/min/m2 and RVEDV 183 ± 89 mL/min/m2 on cardiac magnetic resonance imaging. The mean pre-operative QRS duration is 136 ± 26 ms. The commonest site of latest activation was the RV free wall and DDD pacing here alone or combined with RV apical pacing resulted in significant increases in cardiac output (CO) vs. AAI pacing (P < 0.01 all measures). DDDRV alternative site pacing significantly improved CO by 16% vs. AAI (P = 0.018), and 8.5% vs. DDDRV apical pacing (P = 0.02). Conclusion Single-site RV pacing targeted to the region of latest activation in patients with RBBB undergoing PVR induces acute improvements in haemodynamics and supports the concept of ‘RV CRT’. Targeted pacing in such patients has therapeutic potential both post-operatively and in the long term

Cognitive Dysfunction in Adult Chd With Different Structural Complexity

OBJECTIVE: We carried out a cross-sectional study to assess cognitive function in a sample of adult CHD patients, within the Functioning in Adult Congenital Heart Disease study London. The association between cognitive functioning and disease complexity was examined. METHODS: A total of 310 patients participated in this study. Patients were classified into four structural complexity groups – tetralogy of Fallot, transposition of the great arteries, single ventricle, and simple conditions. Each patient underwent neuropsychological assessment to evaluate cognitive function, including memory and executive function, and completed questionnaires to assess depression and anxiety. RESULTS: Among all, 41% of the sample showed impaired performance (>1.5 SD below the normative mean) on at least three tests of cognitive function compared with established normative data. This was higher than the 8% that was expected in a normal population. The sample exhibited significant deficits in divided attention, motor function, and executive functioning. There was a significant group difference in divided attention (F=5.01, p=0.002) and the mean total composite score (F=5.19, p=0.002) between different structural complexity groups, with the simple group displaying better cognitive function. CONCLUSION: The results indicate that many adult CHD patients display impaired cognitive function relative to a healthy population, which differs in relation to disease complexity. These findings may have implications for clinical decision making in this group of patients during childhood. Possible mechanisms underlying these deficits and how they may be reduced or prevented are discussed; however, further work is needed to draw conclusive judgements

A numerical investigation of the sound intensity field in rooms by using diffusion theory and particle tracing

This work focuses on the calculation of net intensity vectors in rooms, by using two different methods: a geometrical method, based on particle tracing, and the room-acoustic diffusion theory. The classical assumption for diffuse reverberant sound fields is that the acoustic energy flow at any location in room, i.e., the acoustic intensity is null. The reverberant field in rooms with homogeneous dimensions and uniform absorption coefficients is usually considered as diffuse. This study focuses first on the spatial structure of the intensity vector field in such rooms, showing that, although the energy density variation is weak, an organized structure of energy flows can be observed throughout the room. According to the room absorption and reflection law, the deviation of the intensity field from the prediction given by diffuse sound field theory can then be significant. For such rooms, the validity of the room-acoustic diffusion theory is also assessed by numerical calculations of the true diffusion coefficient, by considering both intensity and energy density as given par the particle-tracing model. In a second part, the net intensity field in more complex rooms, such as, for example, long rooms, will be investigated in the same way. The influence of parameters, such as the absorption coefficient and reflection law of the surfaces will be considered. Some numerical calculations of the room-acoustic diffusion coefficient will also be provided, to evaluate the validity of the diffusion theory

A numerical and experimental validation of the room acoustics diffusion theory inside long rooms

This paper focuses on the validation of the recently proposed room-acoustics diffusion theory for the propagation of sound in enclosures by means of numerical simulations and experimental measurements. In particular, the analysis aims to verify the equation underlying the model (Fick’s law of diffusion), which states that the reverberant energy density gradient and the sound intensity inside a room are proportional through a constant diffusion coefficient. In this work the involved acoustic quantities are numerically/experimentally derived under stationary conditions and their ratio is employed to estimate the effective value of the diffusion coefficient inside long rooms. The numerical study was carried out with a set of particle-tracing simulations. The measurements were performed with a Microflown® three-dimensional sound intensity probe inside a 1:16 scale model of a long room, varying the absorption and the scattering properties at the boundaries. A comparison between numerical and experimental results is carried out with a least-square algorithm, showing a fair agreement between the diffusion coefficients estimated with the two methods. The results lead to the conclusion that the reverberant sound field inside long rooms can be described by a non-homogeneous diffusion process: the local diffusion coefficient is not a constant inside the room but increases with the distance from the source and depends on the acoustical properties of the room boundaries

An experimental analysis of the relationship between reverberant acoustic intensity and energy density inside long rooms

The recently developed room-acoustics diffusion model relies on the basic assumption of the Fick's law of diffusion, relating the acoustic intensity and the energy density inside a room, through a constant diffusion coefficient. This study investigates the relationship between these two acoustic quantities in the stationary state, for the particular case of long rooms with different amounts of boundary scattering, by means of experimental measurements. The experiments consist in measurements inside the scale model of a long room, where a three-dimensional Microflown probe (calibrated with digital filters) was employed to collect data in terms of pressure and axial velocity components. Then, for each receiver position, the intensity and the energy density gradient were derived. The experimental results show that inside long rooms the diffusion coefficient is not a constant but increases with the distance from the source, with a slope depending on the scattering coefficient of the walls. This result implies that, for such long enclosures, the diffusion model should consider a space-varying diffusion coefficient to be more consistent with real phenomena

A numerical investigation of the Fick’s law of diffusion in room acoustics

In this paper the validity of the Fick’s law of diffusion in room acoustics is investigated in the stationary state. The Fick’s law, underlying the room-acoustics diffusion model, assumes a propor- tionality relationship between the local sound intensity and the energy density gradient, the propor- tionality constant being the so-called diffusion coefficient. This relationship, based on an analogy with the behavior of real particles in a scattering medium, is assessed by using a numerical tool simulating the actual dynamics of sound particles in a room. Two types of room geometries are considered: rooms with proportionate dimensions and long rooms. Concerning proportionate rooms the numerical analysis highlights the presence of weak variations of the reverberant energy density, generating an intensity vector pattern which is shown to be correctly described by the theoretical Fick’s law and homogeneous diffusion. Conversely, inside long rooms, an estimate of the local value of the diffusion coefficient is carried out, showing that the reverberant sound field is well described by a spatially varying diffusion coefficient (non-homogeneous diffusion). The rate of increase of the estimated diffusion coefficient depends on the cross-sectional area of the room and on the boundaries absorption coefficient

Psychosocial Risk Factors for Health-Related Quality of Life in Adult Congenital Heart Disease

Background There is variability in the impact of adult congenital heart disease (ACHD) on health-related quality of life (HRQoL). A greater insight into the impact of ACHD may be gained from investigating HRQoL in various diagnostic groups and considering the importance of psychosocial risk factors for poor HRQoL. Objective We compared the HRQoL of people with ACHD with normative data from the general population and among 4 diagnostic groups and identified risk factors for poor HRQoL in ACHD from a comprehensive set of sociodemographic, clinical, and psychosocial factors. Methods We conducted a cross-sectional study with 303 participants from 4 diagnostic groups Simple, Tetralogy of Fallot, Transposition of the Great Arteries, Single Ventricle who completed measures of illness perceptions, coping, social support, mood, and generic and disease-specific HRQoL. Data were analyzed using 1-sample t tests, analysis of variance, and hierarchical multiple regressions. Results There was diminished psychosocial HRQoL in the Simple group compared with the general population. Consistently significant risk factors for poor HRQoL included younger age, a perception of more severe symptoms due to ACHD, depression, and anxiety. Clinical factors were poor predictors of HRQoL. Conclusions The findings highlight the need to develop intervention studies aiming to improve HRQoL in people with ACHD and the routine assessment of illness perceptions and mood problems during key periods in people's lives. This will help address patient misconceptions that could be tackled by clinicians or specialist nurses during routine outpatient appointments and identify people in need of psychological support