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Biomedical subjects

A D Bernstein

Publications and source records attributed to A D Bernstein.

At least 19 recordsLinked to original sources
PubMed1996

Clinical usefulness of risk-stratified outcome analysis in cardiac surgery in New Jersey.

BACKGROUND: The results of aortocoronary bypass grafting are under increasing scrutiny by the Health Care Financing Agency, health maintenance organizations, and the news media. Surgeons and hospital administrators are concerned that erroneous conclusions may be drawn from raw outcome data, which do not reflect the patient's preoperative condition. It is our contention that any realistic comparison of results among surgeons or institutions must take that condition into account through a process of risk management. METHODS: We have developed a statistical model for risk stratification based on data compiled systematically at the Newark Beth Israel Medical Center since 1980. Univariate analysis and stepwise logistic regression are used to identify the most significant risk factors and determine the appropriate weight for each. Our original risk stratification system has now been updated by eliminating the optional fields and reweighting the variables. This has reduced the subjective input and improved the accuracy. RESULTS: Use of the modified system shows good correlation between expected and observed outcomes at our institution and in other cases reported to the New Jersey Department of Health. It has improved the results especially in high-risk cases: in total, a group of 5,336 patients have been assessed by the modified system: the expected mortality overall was 7.2% and the observed mortality was 5.4%. In 1,280 high-risk patients, ie, those with an expected mortality of greater than 11%, the expected mortality was 16.2% and the observed mortality was 12.3%. CONCLUSIONS: Our results suggest a decline in length of hospital stay and beneficial changes in operative procedures. They also indicate that exclusion of high-risk cases will result in only minimal financial savings, perhaps less than 2%.

Analysis of Variance↗
PubMed1995

Instantaneous lead entrapment: an unusual complication of nonthoracotomy implantation of an endocardial defibrillation lead.

Nonthoracotomy implantation of implantable cardioverter defibrillators is performed with transvenous leads that are similar to pacemaker leads and are subject to the same potential problems. We report an unusual complication of lead placement in which an electrode immediately became entrapped in the superior rim of the tricuspid valve, resisting all efforts at removal.

Aged↗
PubMed1995

Methods for assessing drug use prevalence in the workplace: a comparison of self-report, urinalysis, and hair analysis.

A random sample of 1,200 employees of a steel manufacturing plant were randomly assigned to four different self-report methods of assessing illicit drug use: 1) Individual interview in the workplace, 2) group-administered questionnaire in the workplace, 3) telephone interview, and 4) individual interview off the worksite. Urine specimens were collected and analyzed on all 928 subjects participating in the study, and hair analysis was conducted on 307 of the subjects. Although self-reports produced the highest drug use prevalence rate, analyses combining the results of the three assessment methods showed that the actual prevalence rate was approximately 50% higher than the estimate produced by self-reports. The group-administered questionnaire condition produced prevalence rates that were roughly half those of the other self-report methods. The findings cast doubt on the validity of self-reports as a means of estimating drug use prevalence and suggest the need for multiple assessment methods.

Adolescent↗
PubMed1994

The usefulness of a stretch-polyester pouch to encase implanted pacemakers and defibrillators.

This study was undertaken to assess the effects of enclosing permanent pacemaker and ICD pulse generators in a stretch-polyester pouch prior to implantation. Follow-up of 223 patients with oversized pacemakers and with ICDs and 344 with standard-sized pacemaker pulse generators showed that the pouch was effective in decreasing the frequency of pulse generator migration and extrusion.

Defibrillators, Implantable↗
PubMed1994

Report of the NASPE Policy Conference on antibradycardia pacemaker follow-up: effectiveness, needs, and resources. North American Society of Pacing and Electrophysiology.

On May 4-5, 1993, a policy conference was held in San Diego, California, under the sponsorship of the North American Society of Pacing and Electrophysiology (NASPE) to identify the fundamental goals of antibradycardia pacemaker follow-up, evaluate the effectiveness with which it achieves those goals, and formulate specific recommendations as to how it can be made more effective. The conference addressed clinical, administrative, and educational objectives, focusing on existing and potential resources for follow-up testing and the appropriate frequency of their application. The training of physicians and associated professionals engaged in follow-up also was addressed, as were regulatory and reimbursement issues. This report summarizes the conclusions and recommendations arrived at during the conference and subsequently approved by the NASPE Board of Trustees.

Bradycardia↗
PubMed1993

Beep detection technique for immediate documentation of R wave sensing by an implanted defibrillator.

A technique is described for follow-up clinic evaluation and documentation of R wave detection by an implanted defibrillator that emits audible tones upon magnet application whenever an R wave or other signal is sensed. A circuit comprising an electret microphone, an instrumentation amplifier, a high-pass filter, and an envelope detector is used to generate a signal that may be plotted together with a surface-lead electrocardiogram on a two-channel strip-chart recorder. The resulting plot documents the sensing function of the implanted device and serves as an indication of optimal magnet position. Alternatively, the beep detector output could be used to trigger the inscription of fiduciary markers on a single-channel strip-chart recorder equipped with an auxiliary input for this purpose.

Defibrillators, Implantable↗
PubMed1993

North American Society of Pacing and Electrophysiology policy statement. 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 Group (BPEG). It is abbreviated as the NBD (for NASPE/BPEG 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.

Defibrillators, Implantable↗
PubMed1992

Survey of cardiac pacing in the United States in 1989.

A survey of physicians who implant permanent cardiac pacemakers was conducted to identify practice patterns related to pacemaker-implantation frequency, hospital and implantation-facility characteristics, indications for pacing and pulse-generator replacement, preferences regarding device types, pacing modes, follow-up methods and frequency, and type and frequency of pacing-related complications. Questionnaires were sent to 11,414 potential physician respondents and 6 pacemaker manufacturers. Implanters' opinions were solicited regarding such issues as the importance of various device features and capabilities, the appropriateness of practice guidelines, and the efficacy of quality-assurance measures. In 1989, 89,445 primary pacemaker implantations and 21,055 pulse-generator replacements were performed by approximately 7,919 physicians at about 3,400 U.S. centers. Typically, a pacemaker manufacturer's sales representative played an active role in 80% of cases. Since the last survey, which examined pacing practices in 1985, primary implantations of dual-chamber pacemakers increased from 22 to 32%, and the proportion of adaptive-rate pacemakers increased from 1 to 40% of primary implants. The "typical" implanter used bipolar electrode systems in 90% of cases, single-chamber pacemakers in 70%, and the introducer method in 95% of lead placements. Significant differences in practice patterns were found among subsets of the survey respondents. Surgeons tended to work alone, use simpler, single-chamber pacemakers, and leave follow-up to others. Electrode stability tended to be better among implanters in nonacademic environments. The quadrennial survey continues to provide useful information on an easily identifiable and traceable patient population, but the process would be greatly simplified by the adoption of a "universal" reporting system such as that used in Europe.

Adult↗
PubMed1992

Deleterious effects of long-term single-chamber ventricular pacing in patients with sick sinus syndrome: the hidden benefits of dual-chamber pacing.

Nine hundred fifty patients who received three modes of primary pacemaker systems (581 dual-chamber universal [DDD], 84 atrioventricular-sequential ventricular-inhibited [DVI] and 285 ventricular-inhibited [VVI]) over 12 years were studied retrospectively to determine the effect of pacing mode on patient longevity and the subsequent development of chronic atrial fibrillation or flutter. All patients were followed up continuously for 7 to 8 years. Patients were classified according to indication for permanent pacing (sick sinus syndrome or other indication), age at pacemaker implantation (less than or equal to 70 or greater than 70 years) and history of atrial tachyarrhythmia. Fourteen percent of patients developed atrial fibrillation at some time during the study period. Of those, 4% had a DDD pacemaker, 8% had a DVI pacemaker and 19% had a VVI pacemaker. At 7 years, atrial fibrillation was significantly more frequent in the VVI group than in the DDD and DVI groups. In patients with sick sinus syndrome, the incidence rate was even higher in the VVI group but approximately the same in the DDD and DVI groups. Patients in the VVI and DVI groups who had had previous atrial tachyarrhythmia had a significantly higher incidence of atrial fibrillation at 7 years than did those in the DDD group. During the entire period there were 130 deaths in the study group, including 22% of patients with a DDD pacemaker, 38% of those with a DVI pacemaker and 50% of those with a VVI pacemaker. Patient survival at 7 years was lower in the VVI group than in the DDD or DVI groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Strategies for mode selection in antibradyarrhythmia pacing.

A systematic technique is described for selecting an appropriate mode of antibradycardia pacing on the basis of 10 clinical criteria. A computer model of the selection process was developed with input from more than 41 implanting physicians, and implemented together with a database management system for keeping track of mode selections and identifying cases in which the modes selected by the implanters differed from those recommended by the model. The selection technique, which can be used without a computer, is presented in detail with a decision-tree representation of the model and an explanation of the rationale behind each of its 39 possible recommendations.

Algorithms↗
PubMed1991

Extraction of implanted transvenous pacing leads: a review of a persistent clinical problem.

Within a few months of implantation, permanent pacemaker leads become ensheathed in fibrocollagenous tissue. This tissue may anchor the lead so that it is difficult, dangerous, or impossible to remove it. Leads with bulbous or finned tips are particularly resistant to extraction. The risks of applying traction to an entrapped lead include induction of bradycardia or ventricular tachycardia and fibrillation, invagination of the right ventricle, avulsion of the right ventricular myocardium or tricuspid valve, hemopericardium, and cardiac tamponade. Forceful traction may result in uncoiling of the conductor, disruption of the insulation, or complete fracture, leaving an intravascular remnant that may embolize or be a source for thrombosis. Although fixation and abandonment of an inactive chronically implanted lead is frequently appropriate and is known to pose little long-term risk, the retained inactive lead may interact adversely with a new active lead and then increase the risk of venous thrombosis, serve as a potential nidus for infection, or produce spurious electrical sensing signals that may be sensed by the pulse generator. Absolute indications for lead removal are those in which there would be a life-threatening situation if the lead were to remain in situ. In the absence of an absolute indication, the decision to proceed with extraction must be made by weighing the potential for serious morbidity or mortality against risks of the extraction technique. Techniques for lead removal include traction and open cardiotomy operations. When a portion of the lead is intravascular, forceps, snares, baskets, countertraction, or lead-transection devices may be used to retrieve the fragment.

Electrodes, Implanted↗
PubMed1989

Pacemaker-implantation complication rates: an analysis of some contributing factors.

An examination of 632 consecutive pacemaker implantations performed at a single institution by 29 implanting physicians over a 5 year period was made to determine which factors affected the 37 perioperative complications experienced. The introducer method of vein access contributed significantly to the complication rate, which was also related to the number of physician implanters on the staff and the makeup of the implantation teams. Of greatest interest was the substantially large incidence of complications experienced by implanters who performed fewer than 12 implantations per year, and particularly the incidence of lead-related complications.

Electrodes, Implanted↗
PubMed1989

Transvenous pacing: a seminal transition from the research laboratory.

In the late 1950s, nonsurgical catheter therapies for the treatment of various disorders did not exist, although surgery was at its highest level of development in the classic sense: extirpation of organs, incision and drainage, diagnostic biopsy. Today we live in an era of diagnostic and therapeutic methods based on catheters: observation, aspiration, drainage, stretching, and manipulation by means of relatively atraumatic tubes. The development of catheter techniques has spawned undreamed-of specialties, industries, and professional societies. Although catheters had been used before then in research laboratories, Furman's clinical application of electrode-tipped venous catheters in treating patients with complete heart block and Stokes-Adams seizures represents a turning point. This advance may be regarded as the catalytic and seminal event for the growth of catheter technologies, which are so prominent in the world of medicine today, and their application to many fields of medicine and surgery.

Cardiac Catheterization↗
PubMed1989

A method of uniform stratification of risk for evaluating the results of surgery in acquired adult heart disease.

The purpose of the study was to devise a method of stratifying open-heart operations into levels of predicted operative mortality, using objective data that are readily available in any hospital. Following univariate regression analysis of 3,500 consecutive operations, 14 risk factors were chosen that met these conditions. A few factors were excluded because they were insufficiently objective or not always available. An additive model was constructed, using the factors chosen, to calculate the probability of mortality within 30 days. The method was then tested prospectively in 1,332 open-heart procedures at the Newark Beth Israel Medical Center. Patients were categorized in five groups of increasing risk: good (0-4%), fair (5-9%), poor (10-14%), high (15-19%), and extremely high (greater than or equal to 20%). The correlation coefficient of anticipated and observed operative mortality, using the additive model, was 0.99. The operative mortality also correlated closely with complication rates and length of hospital stay. The additive model was compared with a second model based on logistic multiple regression; the resulting correlation coefficient was 0.85. The method was also tested at two other hospitals; although their sample sizes were smaller, the outcomes in each risk group were comparable with those at this institution. The collection of data proved to be acceptably simple for all three centers. This study demonstrates that it is possible to design a simple method of risk stratification of open-heart surgery patients that makes it feasible to analyze operative results by risk groups and to compare results in similar groups between institutions. Wider application of the system is recommended.

Adult↗