No description available.

No description available.

The Implantable Cardioverter Defibrillator (ICD) monitors heart rate and intervenes to treat cardiac arrhythmias by electrical shock or pacing. There is evidence that that the number and type of ICD interventions can adversely affect psychological functioning and reduce quality of life and that this may differ between the sexes. Part I focused on ICD interventions and related factors in 726 patients at 9 London hospitals. Results showed that age, sex and ejection fraction were not significantly related to the number of ICD interventions. Evidence was found for both a circadian and circannual distribution of ICD interventions, with peaks occurring between 8am-12pm and in December/January respectively. Part 11 was based on 309 patients from St George's Hospital. It investigated the hypothesis that both ICD interventions and sex would affect psychological functioning and quality of life. The results showed that the type of ICD intervention did not lead to any statistically significant differences in anxiety, anger, depression or any aspect of reduced quality of life. However females scored significantly higher than males on ICD concerns, anxiety and depression and mental health (p<0.05). In regression analysis older age, left ventricular function and total interventions per patient were significantly associated with physical quality of life (p=0.002) and higher scores on depression and trait anxiety were significantly associated with mental quality of life (p<0.05). Part III investigated the stability of these measures after one year in a subgroup of 136 patients. At the follow-up, patients had significantly higher scores on state depression (p=0.03). On the SF-36 there were significantly lower scores on bodily pain, physical functioning and the physical component summary score (p<0.05). In summary, the evidence from the present study shows that psychological functioning and quality of life differences were related to sex rather than the number or type of ICD interventions

Implantable cardioverter defibrillators prevent Sudden Cardiac Death (SCD) in at-risk populations. Coming to terms with having an ICD, risk of SCD and a long-term condition may be impeded by negative psycho-social effects. Nurse-led psychoeducative support interventions have been trialled with mixed outcomes. As neither usual care or skills and knowledge of nurses delivering interventions were detailed, applicability within UK healthcare was unclear. This clinical trial tested a psychoeducational support intervention with usual care using arrhythmia clinical nurse specialists. Method Sixty-three people awaiting first ICD implant were randomised to usual care (n=33) or intervention (n=30) in one English cardiac centre between April 2009 and July 2011 . 'Treat-and-return' cases could not reliably access arrhythmia nurses preimplant and were therefore excluded. Participants completed validated self-report questionnaires (State Trait Anxiety Inventory-STAI; Beck Depression Inventory-Fast Screen- BDI-FS; COPE inventory; World Health Organisation Quality of Life tool- WHOQoL) pre-implant (T1), 6-weeks (T2) and 6-months (T3) post implant. The intervention was delivered 7-10 days post hospital discharge and following 6-week device check . 110 , Results Forty-nine participants (81 .6% male) completed pre-implant questionnaires (usual care n=25, intervention n=24) and 32/49 repeated these at T2 and T3. No significant differences were found between intervention and usual care groups postintervention. Both groups demonstrated increasing trait anxiety and altered coping over time (intervention group revealed increasing planning [p=0.037] and decreasing mental disengagement [p=0.008] but usual care group demonstrated increased denial [p=0.019]). At T3, denial significantly correlated with heightened state (r=0.573, p=0.010) and trait (r=0.577, p=0.010) anxiety for usual care, likewise BDIFS past failure (r=0.502, p=0.029 STAI-State; r=0.634, p=0.004 STAI-Trait) and selfcriticism (r=0.484, p=0.036 STAI-S; r=0.567, p=0.011 STAI-T). Conclusions and implications for practice Whilst small sample size limits generalisability, correlations between coping, anxiety and depression outcomes warrant further investigation with larger samples. Usual care for people having ICOs revealed inequitable access to psycho-educational support. Nurses are well placed to address these inequalities if appropriately resourced.

No description available.

No description available.

Sudden cardiac death following cardiac arrest is a major killer in the industrialised world. The leading cause of sudden cardiac death are disturbances in the normal electrical activation of cardiac tissue, known as cardiac arrhythmia, which severely compromise the ability of the heart to fulfill the body's demand of oxygen. Ventricular fibrillation (VF) is the most deadly form of cardiac arrhythmia. Furthermore, electrical defibrillation through the application of strong electric shocks to the heart is the only effective therapy against VF. Over the past decades, a large body of research has dealt with the study of the mechanisms underpinning the success or failure of defibrillation shocks. The main mechanism of shock failure involves shocks terminating VF but leaving the appropriate electrical substrate for new VF episodes to rapidly follow (i.e. shock-induced arrhythmogenesis). A large number of models have been developed for the in silico study of shock-induced arrhythmogenesis, ranging from single cell models to three-dimensional ventricular models of small mammalian species. However, no extrapolation of the results obtained in the aforementioned studies has been done in human models of ventricular electrophysiology. The main reason is the large computational requirements associated with the solution of the bidomain equations of cardiac electrophysiology over large anatomically-accurate geometrical models including representation of fibre orientation and transmembrane kinetics. In this Thesis we develop simulation technology for the study of cardiac defibrillation in the human heart in the framework of the open source simulation environment Chaste. The advances include the development of novel computational and numerical techniques for the solution of the bidomain equations in large-scale high performance computing resources. More specifically, we have considered the implementation of effective domain decomposition, the development of new numerical techniques for the reduction of communication in Chaste's finite element method (FEM) solver, and the development of mesh-independent preconditioners for the solution of the linear system arising from the FEM discretisation of the bidomain equations. The developments presented in this Thesis have brought Chaste to the level of performance and functionality required to perform bidomain simulations with large three-dimensional cardiac geometries made of tens of millions of nodes and including accurate representation of fibre orientation and membrane kinetics. This advances have enabled the in silico study of shock-induced arrhythmogenesis for the first time in the human heart, therefore bridging an important gap in the field of cardiac defibrillation research.