Three dimensional ballisto- and seismo-cardiography: HIJ wave amplitudes are poorly correlated to maximal systolic force vector.

Ballistocardiography was recorded in 3-D on a free floating astronaut in space as well as on healthy volunteers participating to the ESA 55(th) and DLR 19(th) parabolic flights campaigns. In this paper we demonstrate further the usefulness of recording and analyzing ballistocardiograms (BCG) in three dimensions. The spatial curves of the displacement, velocity and acceleration vectors are analyzed instead of their individual 2-D components. The maximum magnitude of the force vector is shown to be poorly correlated to the HI and IJ wave amplitude traditionally computed on the longitudinal (feet-to-head) component of acceleration (uni-dimensional BCG). We also suggest that kinetic energy and work are useful parameters to consider for a physiological interpretation of the 3D-BCG. The technique presented is invariant from the axis of representation and provides important novel physiological information. We stress further the need of 3D recordings and analysis techniques for Ballisto- and Seismo-cardiography.

Comparison between EEMD, wavelet and FIR denoising: influence on event detection in impedance cardiography.

During thoracic impedance signal acquisition, noise is inherently introduced and hence, denoising is required to allow for accurate event detection. This paper investigates the effectiveness of Ensemble Emperical Mode Decomposition to filter random noise. The performance of the EEMD method is compared with an optimal FIR filter and wavelet denoising. The IMF selection for signal reconstruction in the EEMD denoising method is optimized using a sequential search. Denoising performance was evaluated by the SNR and the accuracy in event detection after filtering. When all criteria are taken into account, wavelet seems to outperform both EEMD and FIR denoising.

Three-dimensional ballistocardiography in microgravity: a review of past research.

This paper gives a short review of research on ballistocardiography in microgravity and indicates the benefits from this research for the use of BCG as a terrestrial cardiac monitoring system. In the past, 3-D methods required large devices to decouple the subject from the terrestrial environment and hence, BCG on Earth is usually limited to unidirectional recordings of the motion in the head-to-foot direction. However, microgravity provides a suspension-free environment where accelerations can be measured in all directions without the influence of gravity. Microgravity research indicated that along with the acceleration in the head-to-foot direction, the accelerations in the lateral and dorso-ventral direction are important in understanding the physiological forces during a cardiac cycle. Further, lung volume has a large influence on the transmission of cardiac forces to the surface of the body. To date, only the three separate components of the acceleration vector have been analyzed in 3-D BCG studies. Using the true acceleration and displacement vector (orientation and magnitude), rather than the three separate components, may permit more accurate cardiac event detection.

WITHDRAWN: Giant Multiperforated Atrial Septal Aneurysm in a Patient with Paroxysmal Atrial Fibrillation.

The publisher regrets that this was an accidental duplication of an article that has already been published in Eur. J. Echocardiogr., 4 (2003) 154-156, . The duplicate article has therefore been withdrawn.

Behavioural accident avoidance science: understanding response in collision incipient conditions.

Road traffic accidents are the single greatest cause of fatality in the workplace and the primary cause of all accidental death in the US to the age of 78. However, behavioural analysis of response in the final seconds and milliseconds before collision has been a most difficult proposition since the quantitative recording of such events has largely been beyond cost feasibility for road transportation. Here, a new and innovative research strategy is reported that permits just such a form of investigation to be conducted in a safe and effective manner. Specifically, a linked simulation environment has been constructed in which drivers are physically located in two adjacent, full-vehicle simulators acting within a shared single virtual driving world. As reported here for the first time, this innovative technology creates situations that provide avoidance responses paralleling those observed in real-world conditions. Within this shared virtual world 46 participants (25 female, 21 male) were tested who met in two ambiguous traffic situations: an intersection and a hill scenario. At the intersection the two drivers approached each other at an angle of 135 degrees and buildings placed at the intersection blocked the view of both drivers from early detection of the opposing vehicle. The second condition represented a 'wrong' way conflict. Each driver proceeded along a three-lane highway from opposite directions. A hill impeded the oncoming view of each driver who only saw the conflicting vehicle briefly as it crested the brow of the hill. Driver avoidance responses of steering wheel, brake, and accelerator activation were recorded to the nearest millisecond. Qualitative results were obtained through a post-experience questionnaire in which participants were asked about their driving habits, simulator experience and their particular response to the experimental events which they had encountered. The results indicated that: (1) situations have been created which provided avoidance responses as they have been recorded in real-world circumstances, (2) the recorded avoidance responses depended directly upon viewing times, and (3) the very short viewing times in this experiment resulted in a single avoidance action, largely represented by a random choice of swerve to either right or left. The present results lead us to posit that in order to be able to design accident avoidance mechanism that respond appropriately in the diverse situations encountered, there is a need to pay particular attention to mutual viewing times for drivers. The general implications for a behavioural science of collision-avoidance are evaluated in light of the present findings.

Giant multiperforated atrial septal aneurysm in a patient with paroxysmal atrial fibrillation.

With the widespread use of transoesophageal echocardiography, atrial septal aneurysm (ASA) is frequently and easily recognized. Diagnostic criteria, however, remain arbitrary. A meticulous search for interatrial shunting (most often patent foramen ovale (PFO)) and associated cardiac diseases is important. ASA is considered a risk factor for cardioembolism, especially in association with patent foramen ovale. We describe a patient with a giant multiperforated ASA presenting with refractory paroxysmal atrial fibrillation. Resection of the aneurysm was performed in combination with a surgical Maze procedure.