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Biomedical subjects

V Barbaro

Publications and source records attributed to V Barbaro.

10 recordsLinked to original sources
PubMed1991

New algorithm for the detection of the ECG fiducial point in the averaging technique.

The use of the coherent averaging technique applied to the electrocardiographic signal implies the location of a fiducial point as a synchronisation reference. An algorithm easily adaptable to a personal computer, operable in real time, insensitive to mains and to ECG-baseline fluctuations, with a low jitter value and the capacity to trigger any ECG signal wave or complex, has been developed. The algorithm detects those waveforms which, within certain confidence intervals, are morphologically equal to a reference wave. This wave is chosen by the user as the repetitive waveform within which the fiducial point is to be located. A two-window template and differential parameters are used. The possibility of building the template permits the user to adapt the algorithm to each patient's ECG. To evaluate its accuracy objectively, a software simulation was built of a generator capable of producing test signals as the sum of the 'useful' signal plus 'noise'. A jitter standard deviation of 1.65 ms was obtained in the worst test (SNR = 10 dB; noiseband = 0-50 Hz), which shows the excellent recognition accuracy of the algorithm.

Algorithms↗
PubMed1991

Prosthetic heart valve evaluation in vitro: critical aspects of data comparability.

The technology of heart valve substitution has considerably improved in the last few years, but its reliability after implantation is still not good enough, hence the need to study new valve design and improve quality testing. Different pulse duplicators are used for heart valve testing, but the results depend very much on the system adopted and the measurement protocol. Tests on two pulse duplicators currently used at the Biomedical Engineering Laboratory at the Istituto Superiore di Sanità, Rome, are reported here. The most significant parameters for valve evaluation were measured following each system's own protocol. Attention was focused on vascular load tuning when setting up the system and on the relationship between drive unit flow waveform and valve regurgitation and energy loss measurements. Standardization criteria must be defined in order to ensure the reliable comparability of in vitro testing results.

Coronary Circulation↗
PubMed1988

Pacemaker registration electronic-card. A proposal for a computerised system of storing of the pacemaker registration card.

This paper describes an example of a computerised system dedicated to store an Emergency Health Card into a compact and portable memory support such as the CMOS RAM CARD. Details are given from the system used and of the program developed for this task. In particular, patient, pacemaker and lead data are stored by the prototype system. The acquisition layout is similar to that of the European pacemaker registration card but some other sections are added. The possibilities of an introduction of a card system like this on E.E.C. countries is discussed.

Computer Systems↗
PubMed1985

Implant effects on polyurethane and silicone cardiac pacing leads in humans: insulation measurements and SEM observations.

Recently, polyurethane cardiac pacing leads have been under discussion because of some failures, probably due to modification of surface insulating properties. In order to verify the reliability of polyurethane versus silicone rubber as coating material, the authors, starting from previous clinical research, have carried out a study of electrical insulation related to implant time. At the same time the outer and inner lead surfaces have been submitted to scanning electron microscope (SEM) analysis. The results show, for the polyurethane leads, a significant increase in the leakage or currents in explanted samples, and a significant degradation (cracking) of the outer surfaces.

Electric Conductivity↗
PubMedDate not supplied

In vitro evaluation of prosthetic heart valves: towards comparable testing.

The Laboratory of Biomedical Engineering (of the National Health Institute, technical body of the Italian Health Service) performs in vitro testing of prosthetic heart valves for mechanical characteristics of materials, fatigue life, and fluidodynamic performance. Testing of materials is directed towards the physicomechanical characterization of the structural components of the valves, e.g. elasticity and resistance to stress of biological tissues and stents. Long-term fatigue life tests are conducted by means of systems which make valves beat at more than 1200 cycles/min. These tests are preceded and followed by geometrical characterization and by steady flow testing in order to obtain information about stenosis and leakage. Special attention is devoted to pulsatile flow testing which is performed on two pulse duplicators: the Dynatek system and the system developed by the University of Sheffield. The same valve was tested with these systems according to their different possible set-ups within the general requirements established by ISO-DIS 5840. This paper presents significant measurements, taking into account their dependence on the systems adopted. Results show (a) the difficulties in comparing test results because of different operating conditions, and (b) the systems' sensitivity with regards to some parameters which affect measurements under comparable set-up conditions (FDA Interlaboratory Comparison Testing Protocol).

Biomechanical Phenomena↗