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Biomedical subjects

S Furman

Publications and source records attributed to S Furman.

At least 217 records · Page 12Linked to original sources

Optimal resources for implantable cardiac pacemakers.

In this document, the 1974 Inter-Society Commission for Heart Disease Resources (ICHD) report, Implantable Cardiac Pacemakers, has been revised and updated to emphasize the increased complexity of present-day pacing, to propose realistic guidelines for various aspects of pacing practice, and to identify the resources needed for delivery of this important mode of health care. The first section of the report describes the several types of pacemakers currently available, how they function, and how and to what purpose they may be modified through noninvasive programming. Recommendations are given for a modified and updated version of the widely accepted ICHD code for identification of pacing modes. The emphasis of the second section of the report is on physical and personnel resources. Matters considered in some depth include the training and qualification of the various medical, technical, and paramedical specialists involved in an implantation procedure; requirements for, and methods of achieving, short- and long-term surveillance of pacemaker patients; and the role of the hospital, the manufacturers, and the FDA in this new era of complex dual-chamber, multiprogrammable pacemakers.

Arrhythmias, Cardiac↗

Implantation of atrioventricular synchronous and atrioventricular universal pacemakers.

Implantation of pacemakers which sense in the atrium and the ventricle requires understanding of both antegrade conduction, from the atrium to the ventricle, and retrograde conduction, from the ventricle to the atrium. Of 53 patients undergoing pacemaker implantation, 25 (47%) had retained VA conduction and 25% of those with complete heart block had 1:1 retrograde (VA) conduction. Determination of both conduction intervals is made by recording the intrinsic deflections of the atrium and the ventricle and measuring the interval. Antegrade intervals (IDA leads to IDV) for those with intact conduction ranged from 189 to 325 msec (mean 212 msec). Retrograde intervals (StV leads to IDA) for those with intact VA conduction ranged from 110 to 346 msec (mean 235 msec). Of 16 patients having VDD and DDD pacemakers implanted without conduction studies, seven (44%) developed pacemaker-mediated tachycardia. The prevention of pacemaker-mediated reentry tachycardia requires knowledge of the VA conduction interval (if it exists) and programming of the atrial refractory period so that retrograde P waves fall within it and are unsensed.

Electrocardiography↗

Role of implantable pacemakers in control of recurrent ventricular tachycardia.

Implanted pacemakers can provide a viable alternative to pharmacologic therapy or surgical management of patients with recurrent ventricular tachycardia. An increasing variety of pacemaker techniques are proving useful for preventing, controlling the effective rate of or terminating ventricular tachycardia. To assess the role of permanent pacing in the treatment of ventricular tachycardia, a consecutive series of 160 patients undergoing electrophysiologic testing for recurrent ventricular tachycardia were analyzed. Thirty-nine patients received implantable pacemakers, of which 13 were intended for bursts of rapid ventricular pacing. No adverse responses were attributed to these burst pacemakers, but concern for possible acceleration of tachycardia and appropriate identification of the arrhythmia were among factors limiting more widespread use of antitachycardia pacing. Some of these limitations may be resolved with further advances in electrophysiologic understanding of arrhythmias combined with strides in medical electronics, which will permit the development of new generations of highly sophisticated antitachycardia pacemakers.

Adult↗

Intracardiac electrode detection of early or subendocardial ischemia.

Subendocardial and early transmural ischemia may have significant clinical consequences while manifesting few ECG changes. Catheters were designed to be introduced transvenously into the right ventricle (RV), and coronary sinus (CS) and transarterially into the left ventricle (LV). The intracavitary electrodes were modified so that the electrodes would not contact the endocardium. In twenty-two dogs ninety-eight graded stenoses of the circumflex and left anterior descending coronary arteries were performed while electrograms (EGM) were recorded simultaneously from the intracardiac (IC) electrodes and surface ECG. Of those stenoses resulting in only nonspecific ECG changes, there were specific ischemic changes on 100% of LV, 60% of RV, and 89% of CS electrograms. Of those stenoses which resulted in no ECG change, there were specific ischemic changes in the 9/31 (29%) of LV, 3/31 (10%) of RV, and 6/31 (19%) of CS electrograms. Recognizable patterns of change occur on the intracardiac electrograms in response to both stenosis and reperfusion, earlier than any change on the ECG. Besides being more sensitive, intracardiac electrodes allowed for the detection of ischemia even in the presence of intraventricular conduction defects, strain patterns, and possibly other situations which might otherwise mask ischemic changes on the ECG.

Animals↗

Endless loop tachycardia in an AV universal [DDD] pacemaker.

Implantation of an AV universal [DDD] pacemaker, stimulating and sensing both atrium and ventricle caused a pacemaker mediated tachycardia, begun by a P wave occurring after a premature ventricular contraction, and sustained by P waves caused by retrograde AV conduction. The tachycardia was terminated by application of a magnet to the pulse generator which temporarily made it insensitive to incoming signals, both P and QRS.

Bradycardia↗

Pacemaker longevity.

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Arrhythmias, Cardiac↗

A new symbolic language for diagramming pacemaker/heart interaction.

A new symbolic language is presented that can be used to diagram pacemaker/heart interactions. The language symbolically indicates "normally" conducted and ectopic events; pacemaker stimuli; pacemaker capture of the chamber; triggered pacemaker stimuli by "normal" or ectopic events; as well as such anomalous pacemaker/heart interactions as failure to sense; "crosstalk" between electrodes; and "normal," ectopic, or paced events in one chamber sensed by the electrode in the other chamber. In addition, symbols are provided to represent antegrade and retrograde accessory pathway conduction, and electronic and physiological refractory intervals. A common baseline is used to separate symbols for atrial activity, above the baseline, from those for ventricular activity, below the baseline. Parallel baselines are used to plot refractory intervals. Thus, even complex dual-chamber pacemaker operating modes can be represented with intrinsic and stimulated cardiac response to pacemaker operation. The language can be sketched out informally for description of general concepts or drafted on millimeter grid paper to make precise timing notations. It is especially useful for interdisciplinary communication of ideas about complex pacemaker/heart interactions.

Atrial Function↗

Cardiac pacing-1981.

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Arrhythmias, Cardiac↗

Night calls. A survey in general practice.

A survey of night calls, executed over a 1-year period between 18h00 and 06h30 the next morning, is presented. Reasons for calls are compared with those in similar surveys carried out in the UK.

Adolescent↗