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This paper investigates the ability of binaural recording and reproduction to be used for measuring the detectability of reversing alarms in laboratory experiments. A complex and repeatible scenario was created using a wave-field synthesis system (WFS), and in-situ recordings in a lime mine. The reproduced sound field was further recorded with a dummy-head. Participants were asked to achieve a visual task (target tracking) while detecting two types of reversing alarms (tonal and broadband), mimicking an approaching vehicle. The experiment was conducted twice : at the center of a WFS array and in a sound-proof booth, using binaural recordings presented with headphones. Results showed that the detection times measured using binaural listening were significantly different from those measured in a fully immersive sound field reproduction. These differences were also greater with tonal sounds compared to broadband sounds. This study shows the limitations of the binaural technique to be used for such applications.

The article discusses the implementation of an active system to enhance the low-frequency sound insulation of double-glazed partition walls. It mentions the controller synthesis methods, both numerically and experimentally, and highlights the superiority of minimizing the transmitted wave over minimizing the acoustic pressure in the partition's cavity for optimal insulation.

The article focuses on the use of Harmonic Acoustic Pneumatic Sources (HAPS) to address the issue of turbofan noise near airports. It mentions the dynamics of HAPS, controller design for active noise control, and outlines an experimental setup to validate the control strategy, aiming for a convergence time of less than a second.

The French multicenter experience (6 centers) of dynamic cardiomyoplasty was analyzed for long-term survival and functional outcome, the most important endpoints in congestive heart failure therapy. Cardiomyoplasty was performed in 212 patients with symptoms of chronic heart failure despite maximal pharmacological therapy. The etiology was ischemic (48%), idiopathic (45%) or other (7%). Cardiomyoplasty was performed using the latissimus dorsi muscle which was electrostimulated after surgery. During follow-up, 88% of patients improved clinically. Hospital death occurred in 29 (14%) patients and was related to the severity of preoperative heart failure symptoms. Late mortality occurred in 99 patients due to heart failure (44%), sudden death (37%), or noncardiac causes (18%). Combined dynamic cardiomyoplasty and implantation of a cardiac rhythm management system was safely achieved in 22 patients, and 26 underwent heart transplantation for recurrent heart failure. Long-term functional improvements were observed in most patients, and the best outcome was achieved in those with isolated right ventricular failure. Dynamic cardiomyoplasty can be considered as a destination therapy or a mid- to long-term biological bridge to heart transplantation. [ABSTRACT FROM PUBLISHER]

Routinely the latissimus dorsi (LD) muscle is stimulated with bursts of pulses at 30 pulses/sec after cardiomyoplasty to assist the failing heart. At a lower pulse frequency the contractile force decreases and at higher frequencies the energy demand of the pacemaker increases rapidly. We investigated The effect of the stimulus frequency variation on contractile force in untrained LD muscles and in muscles after 12 weeks of continuous cyclic electrical stimulation. In six dogs, two electrodes (Medtronic SP5528) were implanted in the left LD muscle together with an Itrel muscle stimulator. The LD muscle was stimulated with 30 pulses/sec in bursts to deliver initially 30 and after 10 weeks 80 contractions per minute. Both before and after training of the LD muscle maximum force was observed by stimulating with a frequency of 36 to 130 pulses/sec in a burst. However, training induced a shift in the steep part of the force-frequency relation to lower frequencies. In particular, at 15 pulses/sec 60% of the maximal force was obtained in contrast to 40% before training. A fatigue test of 8 minutes duration was performed specified by 100 bursts/min and a burst duration of 0.25 sec at pulse frequencies of 30, 36, 50, and 85 pulses/sec. The contractile force decreased significantly during the course of the test at all frequencies. However, the force obtained with 30 pulses/sec stimulation was lower during the initial phase and approximately 10% higher at the end of the fatigue test as compared to 36, 50. and 85 pulses/sec stimulation. We conclude that when the LD muscle is demanded to assist a failing heart by contracting 100 times a minute, pulse trains with a frequency of 30 pulses/sec deliver a near maximal contractile force (80%) and are significantly less fatiguing in comparison to pulse trains at higher frequencies. This indicates that LD muscle stimulation after cardiomyoplasty should be performed at 30 pulses/sec. [ABSTRACT FROM AUTHOR]

PURPOSE Optimization of AV timing is important in heart failure(HF) patients treated with cardiac resynchronization therapy(CRT). An implanted hemodynamic monitor(IHM) can be used for continuous recording of cardiac filling pressures in HF patients. We hypothesized, that the IHM might be helpful in identifying the optimal AVdelay. METHODS 10 patients with heart failure, successfully treated by CRT(InSync III®), (LVEF 24±9%, LVEDD 64±11mm) were also implanted with an IHM (Chronicle®, Medtronic Inc) that continuously records RV systolic/diastolic pressures and an estimation of the pulmonary artery diastolic pressure (PAD), reflecting left atrial filling pressures. The IHM consists of a memory device and a RV lead with a pressure sensor. First, AV delays were optimized by echo (Ritter method). Then, different AV-delays (50-190 ms) were randomly programmed using steps of 20 ms. The PAD was calculated as a 20s median, 40-60s after programming was changed. A low PAD value was considered optimal. Measurements were repeated 1 week later under the same conditions. The Mann-Whitney U test was used to compare differences within the groups. RESULTS No adverse events were associated with dual device implant. One patient was excluded due to AF. Using the IHM, a U-shaped curve was obtained, indicating an optimal AV delay slightly longer as compared with echo. Shortening the AV interval resulted in increased PAD (Tab. 1). The relatively low PAD at +60 ms may be associated with fusion beats at longer AV-delays. These observations were consistent in the repeated tests. CONCLUSIONS The IHM was helpful in identifying the optimal AV-delay in HF patients treated with CRT. In the future, a hemodynamic sensor may be incorporated in CRT devices for long-term recording of filling pressures and allow for hemodynamic device optimization during daily living activities. [ABSTRACT FROM PUBLISHER]

Abstract: Objective: Dynamic cardiomyoplasty (CMP) was proposed as a treatment for refractory heart failure; more than 2000 procedures have been performed worldwide. Heart transplantation was indicated afterwards in some CMP patients with recurrent heart failure symptoms. This study reviews the multicentric French experience with CMP followed by heart transplantation. Methods: From 1985 to 2007, 212 patients (mean age 53±11 years) with refractory heart failure (LVEF=22±9%, mean NYHA 3.2) underwent CMP in France. Heart transplantation was performed in 26 patients (12.3%), mean age: 51±11 years, within 2.3±3 years after CMP. Transplantation was indicated for persistent heart failure, i.e. no immediate improvement after CMP (19%) and for recurring heart failure (81%). Results: The surgical technique of heart transplantation following cardiomyoplasty presents few particularities. Routine extracorporeal bypass was instituted between the vena cavas and the ascending aorta. As in most of these patients the CMP procedure had been performed without the need of extracorporeal circulation, hearts were free of previous cannulations for cardiopulmonary bypass. The latissimus dorsi muscle flap was divided as far as possible inside the left pleural cavity and its vascular pedicle was obturated. The proximal portion of the muscle as well as the muscular pacing electrodes were kept in place in the pleural cavity. The adhesions between the flap and the heart were not released so as to achieve an en bloc resection of the heart and the muscle flap. During removal of the recipient''s heart, care was taken not to injure the left phrenic nerve that was frequently in tight relation with the latissimus dorsi muscle. Heart transplantation was then performed in a routine manner, the donor heart being anastomosed to remnant atria and great vessels. Mean follow-up was 5.5 years (longest 13.5 years). Survival at 10 years was 40% for early heart transplantation (done within 4 months of CMP) and 57% for transplantation performed at 3±2.8 years after CMP. Conclusions: Heart transplantation after CMP is technically feasible. Hospital mortality was higher when urgent transplantation was required. Long-term survival results are similar to those for primary heart transplantation. Cardiomyoplasty, when it fails, does not preclude transplantation, and when indicated, CMP could be considered as a biological bridge to heart transplantation. [Copyright &y& Elsevier]