Peter P. Tarjan

The NASPE /BPEG Defibrillator Code

A new generic code, patterned after and compatible with the NASPE/BPEG Generic Pacemaker Code (NBG Code) was adopted by the NASPE Board of Trustees on January 23. 1993. It was developed by the NASPE Mode Code Committee, including members of the North American Society of Pacing and Electrophysiology (NASPE) and the British Pacing and Electrophysiology Croup (BPEC). It is abbreviated as the NBD (for NASPE/BPEC Defibrillator) Code. It is intended for describing the capabilities and operation of implanted cardioverter defibrillators (ICDs) in conversation, record keeping, and device labeling, and incorporates four positions designating: (1) shock location; (2) antitachycardia pacing location; (3) means of tachycardia detection; and (4) antibradycardia pacing location. An additional Short Form, intended only for use in conversation, was defined as a concise means of distinguishing devices capable of shock alone, shock plus antibradycardia pacing, and shock plus antitachycardia and antibradycardia pacing.

Optimization Of Multi-ring Sensing Electrode Set

The potential generated in a set of concentric ring electrodes by a moving dipole layer has been simulated by a linear finite element model. The wavefront was represented by rectangular charged elements with the charge concentrated at the center of each element. The results were described in a previous paper. The model was refined to reflect the solid angle described by the corners of the finite element and the center of the element on the ring of interest. This corrected the potential while the dipole layer was near the center of the sensing electrodes. The model confirmed that the far-field dependence of both bipolar and tripolar rings was a function of r-4. As expected, the tripolar configuration is more spatially sensitive with a smaller amplitude. When signal amplitude is more important than spatial specificity then the bipolar configuration appears superior.

Fractionated Premotor, Motor, and Ankle Dorsiflexion Reaction Times in Hemiplegia

Ten hemiplegic subjects completed 20 rapid dorsiflexions of their afflicted and nonafflicted limbs. Electrodes were attached to the tibialis anterior and the gastrocnemius muscles and electromyograms were recorded for their premotor time, motor time, and simple reaction time during ankle dorsiflexion and plantar flexion of their lower limbs. The fractionated components of reaction time, namely, premotor time and motor time, of both legs were statistically compared. It was found that the premotor time of the subjects stroke-affected limb was significantly slower than the premotor time of the nonaffected limb (control), with no differences between their associated mean motor times. These results supported the hypothesis that a stroke has a deleterious affect upon the central, premotor time processing centers and has no disruptive influence upon the peripheral motor time. Comparing the fractionated components of reaction time (premotor time and motor time), with simple reaction time, the former provided a more sensitive and valid method to detect possible injurious side effects of a stroke upon the brains neuromotor transmission centers and subcenters, and their peripheral, stimulus, response network.

Laplacian electrocardiograms with active electrodes for arrhythmia detection

Laplacian electrocardiogram (LECG) locates the moment of activation (MOA) at an electrode site from the surface of the chest. A tripolar concentric ring sensor provides a small but well-defined localized signal. The instrumentation amplifier (IA) mounted above the sensor is powered by two on-board lithium batteries. Combining the common mode rejection (CMR) of the tripolar concentric ring sensor and the high common mode rejection ratio (CMRR) of the IA, the LECG signal can be obtained with a good signal to noise ratio (SNR) in real time. Different MOA were observed for each of the 16 sites for each subject. Beat to beat time shift changes were observed at the same site in one subject with bigeminal rhythm. Normal sinus rhythm (NSR) time delay pattern can be used to compare with abnormal ones. Fast arrhythmia classification can be achieved in real time without digital signal processing.

Principles of multimode pacing

En dépit de la proliferation des systémes de stimulation dits physiologique, ľanalyse de leur fonction par ľéléctrocardiogramme est restée complexe. Une meilleure méthode ?analyse est done necessaire pour aider le clinicien à mieux comprendre les systemes DDD. Le dialogue entre fabricant et clinicien doit done rester toujours ouvert.

A computer program to acquire, analyze and track the heart rate variability of patients in a clinical research environment

We present a computer program for the data acquisition, analysis and demographic database of patient data for clinical research. The originality of the method is in the development of a single application program for all 3 major functions.

Directional Depolarization Sensors Of Body Surface ECG

Spatially differentiating rectangular body surface electrodes have been designed and fabricated on the basis of computer simulations of the potential generated on the electrodes by propagating dipolar wavefronts. The electrodes were also tested on human subjects for their ability to detect atrial and reject ventricular depolarizations. The results are encouraging although further refinements are needed for practical use. The reliable and selective detection of atrial activity is important in arrhythmia diagnosis, especially in ambulatory and intensive care monitoring. Our earlier work was aimed at arrhythmia recognition by utilizing spatial discrimination to detect local activation and

In Vivo Detection And Classification Of Cardiac Rhythms Using Concentric Ring Electrodes

Based on previously reported computer simulations and tank experiments1, we have developed a triangulation method to to detect and classify cardiac rhythms. The method is based on using omnidirectional concentric ring electrodes which are sensitive to local activation. Following extensive computer simulations, concentric, planar ring electrodes were tested in vitro. Selectivity is due to spatial differentiation, which is useful to determine the moment of depolarization near the electrodes. The signature of a specific depolarization pattern is characterized by the delays in depolarization among the three sensors. The origin of the depolarization is not necessary for classifying the arrhythmia. The signature depends only on the activity in the region of the triangle. This method is used to study arrhythmias in dogs with chronic epicardial implantation of concentric ring electrodes .

Cardiovascular anatomy, physiology and engineering: a distance learning course

A pilot study in the development of a Computer Supported Distance Learning (CSDL) course was completed. Its subject was cardiovascular physiology, anatomy as well as diagnostic and therapeutic devices. Its target was a class of first year graduate students in biomedical engineering with undergraduate degrees in other engineering disciplines. The format of CSDL seems to overcome many of the problems of our conventional course: Unified Medical Sciences, a course team-taught by physicians and life scientists, as the CSDL format allows self-paced study, exploration of unfamiliar areas, skipping unneeded reviews and assisting the students to dig deeper with guidance and possibly with editorial assistance from the developers of the course. Knowledge of the way living systems have evolved to solve challenges may become more necessary for engineers in other disciplines. The pilot study should provide a springboard for the development of suitable course material for such a course.