Survey of cardiac pacing and implanted defibrillator practice patterns in the United States in 1997.

A survey of implanters of permanent cardiac pacemakers and ICDs in the United States during 1997 was conducted to identify present and changing patterns in indications for pacing, implantation techniques, pacing-mode selection, follow-up, and opinions regarding pacing and ICD related issues. This report is an update from 1993 of surveys performed every 4 years for the International Cardiac Pacing and Electrophysiology Society (ICPES). Questionnaires were sent to implanting physicians who were members of the North American Society of Pacing and Electrophysiology (NASPE), and who might, therefore, be expected to be more conversant than others with the state of the art. Four major manufacturers also provided estimates of the numbers of pacemakers and ICDs implanted in the United States from 1994 through 1997. In 1997, approximately 182,000 new rhythm management devices, including 153,000 primary pacing systems and 29,000 ICDs, were implanted, an increase of 24% for pacemakers and 90% for ICDs since 1994. In 1997, pacemaker implantations were performed by about 8,600 physicians working in 3,300 hospitals and 1,000 independent "surgi-centers." From 1994 to 1997, sales in the United States of dual chamber pacemakers rose from 58% to 69% of the total, and adaptive rate systems from 74% to 90%. ICD sales increased by about 29% per year from 18,700 to 35,000 units. This study disclosed significant differences among implanter subcategories and between present and earlier practices, and it provided useful insights into trends in pacemaker and defibrillator practice. Future surveys would be facilitated if a standardized implant registry like that used in Europe were established in the United States.

[Viral infectious and chromosome aberrations in Bank Vole from natural and laboratory populations]. / Virusnye infektsii i khromosomnye narusheniia u Ryzhei polevki iz prirodnykh i laboratornykh populiatsii.

The frequency of chromosome damage was studied in the carriers of virus of the hemorrhagic fever with renal syndrome (Puumala virus) and in noninfected animals from two laboratory colonies and two natural populations of bank vole. In the laboratory colony, where Puumala virus persisted for three years, multiaberrant ("rogue") cells were found in the bone marrow; the mean frequencies of both structural and numeral chromosome abnormalities were significantly enhanced. In the other laboratory colony, no Puumala virus was detected during all 30 years of its existence, but the mean frequencies of structural chromosome damage were increased to the same degree probably due to the prolonged breeding under laboratory conditions, which resulted in suppression of immunity and DNA repair. The voles from the natural populations were more resistant to the clastogenic viral effect, but they also had multiaberrant cells which served as indicators of viral infection. The data obtained support the hypothesis that viral infections increase mutation rate, contributing thereby to the evolution process.

Arthroscopic treatment of an intra-articular lipoma of the knee joint.

Intra-articular lipoma is an exceedingly rare diagnosis. There have been less than 15 documented cases of an intra-articular lipoma of the knee joint. This report presents the first description of an intra-articular knee lipoma treated entirely by arthroscopic methods. Preoperative history, examination, and imaging studies are reviewed. Intraoperative findings, treatment, and postoperative evaluation are discussed as well. Symptomatic intra-articular lipoma of the knee joint can be successfully treated by arthroscopic resection. Differentiating intra-articular lipoma from lipoma arborescens, a similar but more common condition, is important with regards to optimal treatment.

Distal biceps tendon ruptures: a historical perspective and current concepts.

Distal biceps tendon rupture is a relatively rare injury most commonly seen in the dominant extremity of men between 40 and 60 years of age. It occurs when an eccentric extension force is applied to a contracting biceps muscle. The hallmark finding is a palpable defect in the distal biceps, which is accentuated by elbow flexion. Radiographic evaluation is usually not necessary. Acute surgical repair is advocated for optimal return of function by either a one-incision or a modified two-incision muscle-splitting technique. The arm is protected for 6 to 8 eight weeks after surgery. Unrestricted range of motion and gentle strengthening may begin after the 6 - 8 week protection period. Return to unrestricted activity is usually allowed by 5 months after surgery.

Aortic valve replacement in geriatric patients: determinants of in-hospital mortality.

BACKGROUND: Aortic valve replacement is a common procedure in elderly patients. There has been a great deal of controversy about the risks associated with early mortality. Uncertainty of the risk associated with a small valve continues to remain controversial. This study was designed to identify the risk factors influencing early mortality and establish an accurate model for the prediction of in-hospital mortality. METHODS: One hundred eighty septuagenarians and octogenarians (58% women; mean age, 76 +/- 4.7 years) underwent primary isolated aortic valve replacement between 1986 and 1997. There was an overall mortality of 16.7% (n = 180). Patients with a body surface area less than 1.8 m2 had an in-hospital mortality of 23.2% (n = 95) compared with 8.1% (n = 74; p = 0.009) for patients with a body surface area of 1.8 m2 or more. Patients with a cardiopulmonary bypass time of less than 100 minutes experienced an early mortality of 8.9% (n = 56) compared with a 10.2% (n = 59) early mortality for patients on bypass time between 100 and 124 minutes and a 29.6% (n = 64) early mortality in patients with a pump time longer than 124 minutes (p = 0.040). RESULTS: Multivariate logistic regression analysis identified small body surface area and long cardiopulmonary bypass time as independent risk factors. A higher mortality was seen in female patients and patients receiving smaller valves. However, there was a strong correlation between small body surface area, small valve size, and female gender. CONCLUSIONS: Small body surface area and long cardiopulmonary bypass time are two independent risk factors in early mortality for elderly patients undergoing primary isolated aortic valve replacement. The use of small valves does not influence early mortality.

Spontaneous rib fracture during pregnancy. A case report and review of the literature.

No studies have demonstrated a direct relationship between pregnancy and rib fracture. A case of spontaneous rib fracture in the third trimester presents the opportunity to examine factors unique to pregnancy that may predispose the patient to stress fractures of the lower ribs. A 28-year old woman in week 31 of her pregnancy presented with the chief complaint of acute onset of right upper quadrant pain. A chest radiograph demonstrated a minimally displaced fracture of the right 10th rib. During pregnancy, the enlarging uterus causes certain opposing muscular forces to act on the ribs, making them more susceptible to fracture after minimal trauma or after repeated stresses such as a chronic cough.

Patients' attitudes toward implanted defibrillator shocks.

In addition to its beneficial effect on patient survival, the implanted cardioverter defibrillator (ICD) changes a patient's life physically, socially, and psychologically. For improved patient management, it is important to understand the quality-of-life changes that accompany this mode of treatment. To this end, 119 patients were surveyed retrospectively and interviewed concurrently regarding their emotional, physical, and behavioral responses to ICD shocks and to the device itself. Most (55%) correctly estimated the total number of shocks they had received within a 10% margin. They found the shocks severe, 79% assigning a score between 3 and 5 on a scale of 1-5. Common descriptions of the shock sensation were a blow to the body or a spasm causing the entire body to jump. Most patients tolerated the shocks as lifesaving, but 23% dreaded shocks and 5% even said they would rather be without the ICD and take their chances. After a shock, 50% of patients called their physician and 42% continued their daily routine. Thirty percent went to a hospital emergency room or called a rescue service. Sixty-five percent had no preshock prodromes. Fifty-four percent were interested in the programmable option of a warning signal prior to a shock, while 31% preferred no warning. Of the 74% who were advised not to drive after implantation, 29% drove anyway. Five patients were shocked while driving with no resulting accidents. We conclude that most patients find ICD shocks moderately uncomfortable, but they tolerate them because of the lifesaving protection provided by the device.

Serial lead impedance measurements confirm fixation of helical screw electrodes during pacemaker implantation.

The purpose of this study was to determine whether serial measurements of helical screw pacemaker lead impedance could reliably confirm electrode fixation in the right atrium and right ventricle. Fixation is generally assessed fluoroscopically, which can be misleading because the myocardium is radiolucent. Alternatively, because the electrical conductivity of blood is greater than that of myocardium, serial measurements of the lead impedance might be expected to show an impedance increase with appropriate fixation of the pacemaker electrode when the electrode becomes embedded in myocardial tissue. Impedance measurements were made during the placement of 23 atrial and 28 ventricular active fixation electrodes in 31 consecutive patients. Impedance measurements were recorded in unipolar and bipolar electrode configurations with the electrode free floating in the chamber, unfixed (with exposed screws) but touching the endocardial surface, and after fixation. No significant impedance differences were found between free-floating and unfixed electrode positions. With fixation, the lead impedance increased significantly in the ventricle (P = 0.0001, unipolar and bipolar) and the atrium (P = 0.0069 unipolar and 0.0052 bipolar). Typical increases, reflected by median values, were 197 ohms unipolar and 203 ohms bipolar in the ventricle and 47 ohms unipolar and 53 ohms bipolar in the atrium for electrodes with permanently exposed or retractable screw designs. Comparing serial measurements of lead impedance before and after electrode fixation is a valid electrical method of confirming appropriate fixation of helical screw electrodes.

Reduced frequency of retention wire fractures suggests that elective explantation of affected atrial leads is no longer indicated.

Since 1994, 611 patients with atrial Accufix leads have been followed. Consideration was given to explanting these leads based on the presence or absence of fractures of the retention wire. All leads were followed according to a protocol proposed by the manufacturer, chiefly by regular 6-month high quality X rays and fluoroscopic evaluation. The impact of various conditions on the incidence of fracture was evaluated, such as the shape and location of the lead, prior open heart surgery, and the implantation route. The only factor related to the frequency of fractures was the shape of the lead, fractures occurring statistically more frequently if the leads were pulled from their normal J shape into an L or straightened configuration. The frequency of fractures has plateaued at 6 through 9 years with no further occurrence of Class III or IV fractures (protrusion of the fractured segment). Altogether there were nine (1.5%) Class III and Class IV fractures at the 9-year follow-up. Actuarial survival, in Class I or II, was 97%. We concluded, that the frequency of retention wire fractures has plateaued. This information coupled with the knowledge that the Accufix lead extraction can be difficult and dangerous, suggests that the remaining leads are best left in place.

Bedside estimation of risk as an aid for decision-making in cardiac surgery.

BACKGROUND: Evaluations of the cardiac-surgery mortality rates of hospitals and surgeons can be fair and realistic only when the observed mortality rates are compared with expected rates with preoperative risk factors taken into account. Risk-approximation calculations also can assist patients and physicians in discussing the risk of cardiac surgery, especially if the estimation of surgical mortality takes all of the important risk factors into account. METHODS: A logistic regression model was developed in which 47 potential risk factors were considered, and a method requiring only simple addition and graphic interpretation was designed for approximating the estimated risk easily and quickly, with paper and pencil alone. RESULTS: The estimates provided by the simplified model correlated well with the observed mortality rates. CONCLUSIONS: A simple approximation of a logistic regression model has been found to be helpful in discussions between physicians and patients contemplating aortocoronary bypass or valve-related surgery.

Assessing drug use in the workplace: a comparison of self-report, urinalysis, and hair analysis.

A random sample of 1,200 employees of a steel plant in the western United States was randomly assigned to four different self-report methods of assessing illicit drug use: individual interview in the workplace, group-administered questionnaire in the workplace, telephone interview, and 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 higher prevalence rates than the chemical tests, analyses combining the results of the three assessment methods showed that the actual prevalence rate was approximately 50 percent higher than the estimate produced by self-reports alone. The group-administered questionnaire method 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 means of estimating drug use prevalence and suggest the need for multiple assessment methods.