PubMed · 17184679
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Stephen Large. 2007. Invited commentary.. https://doi.org/10.1016/j.athoracsur.2006.06.002
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A 45-year-old man had life-threatening recurrent idiopathic ventricular fibrillation and persistent cardiogenic shock develop. The episodes of ventricular fibrillation were refractory to aggressive medical management; therefore an Abiomed AB5000 bi-ventricular support system was implanted for arrhythmia control. The device was able to maintain hemodynamic stability during the following 2 weeks. The patient was discharged from the hospital with fully recovered cardiac function.
PURPOSE OF REVIEW: Use of electrophysiologic devices (permanent cardiac pacemaker and implantable cardioverter/defibrillator) has been increasing. Infection of these cardiac devices is a devastating complication, and medical treatment alone without device removal is often unsuccessful and frequently leads to infection relapse. This article reviews recent publications that address the diagnosis and management of infected electrophysiologic devices. RECENT FINDINGS: Recent studies have shed new light on the incidence, risk factors, management, and outcome of cardiac device infection. Rates of both cardiac device implantation and infection have been increasing, although the rate of increase of cardiac device infection has outdistanced that of implantation and this has had enormous economic and clinical consequences. SUMMARY: The large majority of cardiac device infections are likely due to pocket site contamination at the time of device placement. Hematogenous seeding from a distant focus of infection, particularly due to Staphylococcus aureus, can account for late-onset infection. Although no prospective studies have been conducted to date, management with parenteral antibiotics and complete device removal is the current standard of care. Further study is needed to better define optimal diagnostic and management interventions, particularly in patients with bloodstream infection and no local chest wall or echocardiographic evidence of cardiac device infection.
This article addresses the growing need for comprehensive tools to investigate the hemodynamics of ventricular assist devices (VADs) in general and sac-type VADs in particular. Numerical simulations can be very helpful in these efforts. However, full simulation of flow inside sac-type VADs poses several key problems, among them simulation of the mechanical heart valves and calculation of the motion of flexible walls. We present a simplified three-dimensional (3D) numerical model of a sac-VAD chamber. The walls in the simplified model are defined to move according to experimental measurements, and the valves are modeled in fully open or fully closed positions. The model is validated by comparison to a fully coupled fluid-structure interaction numerical simulation and to experimental measurements using continuous digital particle image velocimetry. Our results demonstrate that the flexible wall motion is sensitive to changes in pressure distribution inside the chamber. However, small variations in wall motion do not significantly affect the global features of flow inside the chamber. Therefore, the simplified model can be used to predict the 3D time-dependent flow field in the VAD.