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Biomedical subjects

W J Hall

Publications and source records attributed to W J Hall.

At least 19 recordsLinked to original sources
PubMed1995

ECG T-wave patterns in genetically distinct forms of the hereditary long QT syndrome.

BACKGROUND: The long QT syndrome is an inherited disorder with prolonged ventricular repolarization and a propensity to ventricular tachyarrhythmias and sudden arrhythmic death. Recent linkage studies have demonstrated three separate loci for this disorder on chromosomes 3, 7, and 11, and specific mutated genes for long QT syndrome have been identified on two of these chromosomes. We investigated ECG T-wave patterns (phenotypes) in members of families linked to three genetically distinct forms of the long QT syndrome. METHODS AND RESULTS: Five quantitative ECG repolarization parameters, ie, four Bazett-corrected time intervals (QTonset-c, QTpeak-c, QTc, and Tduration-c, in milliseconds) and the absolute height of the T wave (Tamplitude, in millivolts), were measured in 153 members of six families with long QT syndrome linked to markers on chromosomes 3 (n = 47), 7 (n = 30), and 11 (n = 76). Genotypic data were used to define each family member as being affected or unaffected with long QT syndrome. Affected members of all six families had longer QT intervals (QTonset-c, QTpeak-c, or QTc) than unaffected family members (P < .01). Each of the three long QT syndrome genotypes was associated with somewhat distinctive ECG repolarization features. Among affected individuals, the QTonset-c was unusually prolonged in those individuals with mutations involving the cardiac sodium channel gene SCN5A on chromosome 3 (lead II QTonset-c [mean +/- SD]: chromosome 3, 341 +/- 42 ms; chromosome 7, 290 +/- 56 ms; chromosome 11, 243 +/- 73 ms; P < .001); Tamplitude was generally quite small in the chromosome 7 genotype (lead II Tamplitude, mV: chromosome 3, 0.36 +/- 0.14; chromosome 7, 0.13 +/- 0.07; chromosome 11, 0.37 +/- 0.17; P < .001); and Tduration was particularly long in the chromosome 11 genotype (lead II Tduration-c: chromosome 3, 187 +/- 33 ms; chromosome 7, 191 +/- 51 ms; chromosome 11, 262 +/- 65 ms; P < .001). Similar ECG findings were observed in leads aVF and V5. A considerable variability exists in the quantitative repolarization parameters associated with each genotype, with overlap in the T-wave patterns among the three genotypes. CONCLUSIONS: Three separate genetic loci for the long QT syndrome including mutations in two cardiac ionic channel genes were associated with different phenotypic T-wave patterns on the ECG. This study provides insight into the influence of genetic factors on ECG manifestations of ventricular repolarization.

Adult↗
PubMed1995

Risk of cardiac events in family members of patients with long QT syndrome.

OBJECTIVES: This study sought to identify risk factors for cardiac events (syncope, aborted cardiac arrest or sudden cardiac death) in family members of patients with the long QT syndrome. BACKGROUND: Patients with the long QT syndrome are known to be at high risk for cardiac events. Whenever the first member of a family is identified as having the long QT syndrome (proband), there is concern regarding the likelihood of cardiac events in other family members. METHODS: A multivariate logistic regression model was used to evaluate the risk of cardiac events in 637 family members who were first- and second-degree relatives of 151 probands with the long QT syndrome and in a subset of 513 family members who were not receiving beta-adrenergic blocking agents. There were 293 first-degree (46%) and 344 second-degree relatives (54%) (293 men [46%], 344 women [54%]). Fifteen percent of the family members had a corrected QT interval (QTc) > 0.44 s, and relative tachycardia and bradycardia were observed in 12% and 25%, respectively. RESULTS: The risk of cardiac events occurring before age 40 in family members not taking beta-blockers was influenced by the QTc interval (odds ratio [OR] 1.18/0.01 increase in QTc value; 95% confidence interval [CI] 1.12 to 1.24), relative tachycardia (OR 2.21, 95% CI 0.97 to 5.02) or bradycardia (OR 2.24, 95% CI 1.10 to 4.56) and an interaction term combining gender and closeness of the relationship to the proband (OR for female first-degree relative 3.23 vs. all second-degree relatives, 95% CI 1.67-6.22). CONCLUSIONS: Female first-degree relatives of patients with the long QT syndrome have a higher risk of cardiac events than male first- or second-degree relatives, independent of recorded electrocardiographic findings. Not only bradycardia, but also tachycardia increases risk of cardiac events in family members of patients with the long QT syndrome.

Adolescent↗
PubMed1995

Acute respiratory tract infection in daycare centers for older persons.

OBJECTIVE: To evaluate the rate of specific pathogens and clinical syndromes associated with acute respiratory tract infections (ARTI) in frail older persons attending daycare. DESIGN: Prospective descriptive study, without intervention. SETTING: Two sites of a senior daycare program providing all-inclusive care for the older persons in Rochester, New York. PARTICIPANTS: Staff members and participants of the day-care. MEASUREMENTS: Demographic, medical, and physical findings were collected from older subjects at baseline and while ill with respiratory illnesses. Nasopharyngeal specimens for viral and Chlamydia culture and sputum for bacterial culture were obtained from subjects when ill. Acute and convalescent sera were also collected with each illness and examined for viral, chlamydial, and mycoplasma infection. MAIN RESULTS: One hundred sixty-five illnesses were documented in 165 older daycare participants as well as 113 illnesses among 67 staff members during the 15-month study. The rate of ARTI in the elderly group was 10.8 per 100 person months. The most common etiologies in both the staff and elderly participants were respiratory syncytial virus (RSV), Influenza A, and coronavirus. The etiologies of illnesses in the staff compared with those in elderly group were similar except that bacterial infections were significantly more common among the elderly (7% vs. 0, P = 0.05). Multiple pathogens were found to cocirculate within centers, and no clear outbreak of a predominant organism was noted. Cough and nasal congestion characterized most illnesses. The elderly experienced significantly more cough, dyspnea, and sputum production than did the staff. There were 10 hospitalizations related to respiratory infections and four deaths during the acute illness among the elderly group and none in staff.

Acute Disease↗
PubMed1995

Women's receptivity to testing for a genetic susceptibility to breast cancer.

Four hundred eighty-four patients undergoing mammography and 498 patients visiting their obstetrician-gynecologist were asked whether they would take a breast cancer 1 (BRCA1) test to detect a genetic susceptibility to breast cancer. More than 90% in both groups said they would take the test. Women were more likely to accept if they were regularly having breast examinations by a physician, believed that mammography effectively detects early breast cancer, and believed that early breast cancer is curable. If shown to have inherited a susceptibility, many reported that they would be very anxious, would want the test repeated, would examine their breasts more often than monthly, and would want mammography more often than yearly. Many also reported that they would recommend testing to relatives.

Breast Neoplasms↗
PubMed1994

Comfort care for terminally ill patients. The appropriate use of nutrition and hydration.

OBJECTIVE: To determine the frequency of symptoms of hunger and thirst in a group of terminally ill patients and determine whether these symptoms could be palliated without forced feeding, forced hydration, or parenteral alimentation. DESIGN: Prospective evaluation of consecutively admitted terminally ill patients treated in a comfort care unit. SETTING: Ten-bed comfort care unit in a 471-bed long-term care facility. PARTICIPANTS: Mentally aware, competent patients with terminal illnesses monitored from time of admission to time of death while residing in the comfort care unit. MAIN OUTCOME MEASURES: Symptoms of hunger, thirst, and dry mouth were recorded, and the amounts and types of food and fluids necessary to relieve these symptoms were documented. The subjective level of comfort was assessed longitudinally in all patients. RESULTS: Of the 32 patients monitored during the 12 months of study, 20 patients (63%) never experienced any hunger, while 11 patients (34%) had symptoms only initially. Similarly, 20 patients (62%) experienced either no thirst or thirst only initially during their terminal illness. In all patients, symptoms of hunger, thirst, and dry mouth could be alleviated, usually with small amounts of food, fluids, and/or by the application of ice chips and lubrication to the lips. Comfort care included use of narcotics for relief of pain or shortness of breath in 94% of patients. CONCLUSIONS: In this series, patients terminally ill with cancer generally did not experience hunger and those who did needed only small amounts of food for alleviation. Complaints of thirst and dry mouth were relieved with mouth care and sips of liquids far less than that needed to prevent dehydration. Food and fluid administration beyond the specific requests of patients may play a minimal role in providing comfort to terminally ill patients.

Aged↗
PubMed1994

Computer-based vs manual health maintenance tracking. A controlled trial.

OBJECTIVE: To compare computer-based with manual health maintenance tracking systems to determine whether (1) a computer-based system will result in better provider compliance with the practice health maintenance protocol, (2) the incremental cost of operating a computer-based vs a manual health maintenance tracking system differs, and (3) inactive patients will respond to health maintenance reminders. DESIGN: Two-year prospective, randomized, controlled trial. SETTING: Rural, multiple-office, nonprofit, fee-for-service family practice. PATIENTS: Adult members of families in which at least one member had been seen by the practice within the past 2 years. INTERVENTION: A computer-based health maintenance tracking system that generated annual provider and patient reminders for all patients regardless of appointment status compared with a manual flowchart-based tracking system in which patient reminders were triggered by provider request. OUTCOME MEASURES: Provider compliance with the health maintenance protocol determined by preintervention and postintervention chart audits, costs of computer-based tracking, and response of inactive patients to health maintenance reminders. RESULTS: Overall provider compliance with the health maintenance protocol increased 15 percentage points in the computer-based tracking group and four percentage points in the manual group. The computer-based tracking group had significantly higher provider compliance than the manual group for eight of 11 procedures. The computer-based tracking system cost 78 cents per patient per year to operate. It was not associated with increased office visits or patient billings. CONCLUSIONS: Computer-based health maintenance tracking improved provider health maintenance compliance compared with a manual system. The finding that health maintenance compliance improved without a significant increase in patient visits or billings requires confirmation in other settings but suggests that considerable health maintenance can be incorporated into ongoing patient care.

Adult↗
PubMed1994

T wave alternans in idiopathic long QT syndrome.

OBJECTIVES: The study evaluates the association between T wave alternans and the risk of cardiac events (syncope, aborted cardiac arrest or cardiac death) in a large population of patients with idiopathic long QT syndrome. BACKGROUND: T wave alternans is an infrequently recorded electrocardiographic (ECG) finding in patients with delayed repolarization, and its clinical significance is not clear. METHODS: A total of 4,656 ECG recordings in 2,442 patients enrolled in the International Long QT Syndrome Registry were reviewed for episodes of T wave alternans. To determine the risk associated with T wave alternans, independent of corrected QT interval (QTc) duration, patients with T wave alternans were matched for QTc value (every 0.025 s1/2) to patients with long QT syndrome without T wave alternans. RESULTS: T wave alternans was identified in 30 patients (25 of whom had a QTc interval > 0.50 s1/2). A strong association between QTc prolongation and T wave alternans was observed (odds ratio 1.23 per 0.01-s1/2 unit increase in QTc, p < 0.0001). Conditional logistic regression analyses with adjustment for age, gender, status and QTc value revealed that T wave alternans did not make a significant independent contribution to the risk of cardiac events. The risk of experiencing a major cardiac event was primarily related to length of QTc. CONCLUSIONS: T wave alternans, a marker of electrical instability and regional heterogeneity of repolarization, identifies a high risk subset of patients with prolonged repolarization. Patients with T wave alternans have an increased risk of cardiac events, but this risk is primarily related to the magnitude of repolarization delay (QTc prolongation). T wave alternans does not make an independent contribution to the risk of cardiac events after adjustment for QTc length.

Adolescent↗
PubMed1994

Rates, patterns, causes, and costs of hospitalization of nursing home residents: a population-based study.

OBJECTIVES: Hospitalization of nursing home residents is a growing, poorly defined problem. The purposes of this study were to define rates, patterns, costs, and outcomes of hospitalizations from nursing homes and to consider implications for reducing this problem as part of health care reform. METHODS: Communitywide nursing home utilization review and hospital discharge data were used to define retrospectively a cohort of 2120 patients newly admitted to nursing homes; these patients were followed for 2 years to identify all hospitalizations. Resident characteristics were analyzed for predictors of hospitalization. Charges and outcomes were compared with hospitalization of community-dwelling elders. RESULTS: Hospitalization rates were strikingly higher for intermediate vs skilled levels of care (566 and 346 per 1000 resident years, respectively). Approximately 40% of all hospitalizations occurred within 3 months of admission. No strong predictors were identified. Length of stay, charges, and mortality rates were higher than for hospitalizations from the community. CONCLUSIONS: Hospitalizations from nursing homes are not easily predicted but may in large part be prevented through health care reforms that integrate acute and longterm care.

Aged↗
PubMed1994

Analysis of HLA and disease susceptibility: chromosome 6 genes and sex influence long-QT phenotype.

The long-QT (LQT) syndrome is a genetically complex disorder that is characterized by syncope and fatal ventricular arrhythmias. LQT syndrome, as defined by a prolonged electrocardiographic QT interval, has a higher incidence in females than in males and does not exhibit Mendelian transmission patterns in all families. Among those families that are nearly consistent with Mendelian transmission, linkage between a locus for LQT syndrome and the H-ras-1 locus on the short arm of chromosome 11 has been reported in some families but not in others. Earlier analyses suggesting that LQT syndrome might be caused by a gene in the HLA region of chromosome 6 were not confirmed by standard linkage analyses. Here, we present an analysis of HLA haplotype sharing among affected pedigree members, showing an excess of haplotype sharing in a previously published Japanese pedigree and possibly also in 15 families of European descent. The haplotypes shared by affected individuals derive from both affected and unaffected parents. In an analysis of independent (unrelated) HLA haplotypes, we also found a nonrandom distribution of HLA-DR genes in LQT syndrome patients compared with controls, suggesting an association between the LQT phenotype and specific HLA-DR genes. Our data indicate that DR2 has a protective effect and, particularly in males, that DR7 may increase susceptibility to the LQT syndrome. Thus, LQT syndrome may be influenced by genes on chromosomes 11 and 6, possibly with a sex-specific effect. These results provide a model for an effect of HLA-region genes inherited from either parent on the expression of an illness that may be determined principally by alleles at loci not linked to HLA.

Chromosomes, Human, Pair 6↗
PubMed1992

The location of the receptors involved in the human diuretic response to drinking an isotonic electrolyte solution.

1. This study aimed to shed light on the receptors involved in the diuretic response to drinking isotonic fluids in man by employing a polyethylene glycol-based bowel lavage solution (Golytely) which is reported to cause no net movement of fluid across the gut. 2. Drinking Golytely resulted in a transient hypotonic diuresis. Mean urine flow rose from control values of 0.9 ml min-1 to 10.1 ml min-1 70 min after the start of drinking. The increase in urine output was accompanied by a fall in urine osmolality from control values of 879 mosM kg-1 to 105 mosM kg-1. The diuresis is similar to that produced by ingestion of an equal volume of an absorbable electrolyte-based solution (Tyrode). 3. Neither solution produced changes in plasma osmolality or electrolytes, but Golytely provoked a 6.8% contraction of plasma volume, whereas drinking Tyrode resulted in plasma expansion. Copious diarrhoea was experienced by all subjects who drank Golytely solution and by none on drinking Tyrode solution. 4. The infusion of Golytely into the stomach resulted in a hypotonic diuresis similar in magnitude to that elicited by drinking. Drinking with simultaneous aspiration of gastric contents ('sham-drinking') did not produce a significant diuresis. 5. Plasma arginine vasopressin (AVP) levels did not fall following the drinking of Golytely. The assay used was sufficiently sensitive to measure changes of 0.6 pg AVP (ml plasma)-1. 6. The findings show that signals from the oropharynx do not mediate the diuretic response to drinking Golytely in man and that a mechanism other than inhibition of AVP release appears to be involved. The receptors mediating this response may lie in the stomach and/or small bowel since Golytely is not absorbed, as evidenced by the contraction of plasma volume and diarrhoea.

Adult↗
PubMed1992

Role of the gastrointestinal tract in the regulation of hydration in man.

Research into the role of the gastrointestinal tract in the regulation of hydration has primarily concentrated on its function in the prevention of dehydration. The role of the gut in thirst, in the absorption of fluids and the consequences of diarrhoea are of importance in this respect. The function of the gut in the prevention of overhydration is less well understood. Intake of fluid increases excretion of water by the kidney. Inhibition of arginine vasopressin secretion, activation of renal nerves or hormonal release are possible effector mechanisms in this response.

Animals↗
PubMed1991

The long QT syndrome. Prospective longitudinal study of 328 families.

BACKGROUND: The Long QT Syndrome (LQTS) is an infrequently occurring familial disorder in which affected individuals have electrocardiographic QT interval prolongation and a propensity to ventricular tachyarrhythmic syncope and sudden death. We prospectively investigated the clinical characteristics and the long-term course of 3,343 individuals from 328 families in which one or more members were identified as affected with LQTS (QTc greater than 0.44 sec1/2). METHODS AND RESULTS: The first member of a family to be identified with LQTS, the proband, was usually brought to medical attention because of a syncopal episode during childhood or teenage years. Probands (n = 328) were younger at first contact (age 21 +/- 15 years), more likely to be female (69%), and had a higher frequency of preenrollment syncope or cardiac arrest with resuscitation (80%), congenital deafness (7%), a resting heart rate less than 60 beats/min (31%), QTc greater than or equal to 0.50 sec1/2 (52%), and a history of ventricular tachyarrhythmia (47%) than other affected (n = 688) and unaffected (n = 1,004) family members. Arrhythmogenic syncope often occurred in association with acute physical, emotional, or auditory arousal. The syncopal episodes were frequently misinterpreted as a seizure disorder. By age 12 years, 50% of the probands had experienced at least one syncopal episode or death. The rates of postenrollment syncope (one or more episodes) and probable LQTS-related death (before age 50 years) for probands (n = 235; average follow-up 54 months per patient) were 5.0% per year and 0.9% per year, respectively; these event rates were considerably higher than those observed among affected and unaffected family members. CONCLUSIONS: Among 232 probands and 1,264 family members with prospective follow-up, three factors made significant independent contributions to the risk of subsequent syncope or probable LQTS-related death before age 50 years, whichever occurred first (Cox hazard ratio; 95% confidence limits): 1) QTc (1.052; 1.017, 1.088), 2) history of cardiac event (3.1; 1.3, 7.2), and 3) heart rate (1.017; 1.004, 1.031). The findings from this prospective longitudinal study highlight the clinical features, risk factors, and course of LQTS.

Adult↗
PubMed1991

Case management: a randomized controlled study comparing a neighborhood team and a centralized individual model.

This randomized controlled study compared two types of case management for skilled nursing level patients living at home: the centralized individual model and the neighborhood team model. The team model differed from the individual model in that team case managers performed client assessments, care planning, some direct services, and reassessments; they also had much smaller caseloads and were assigned a specific catchment area. While patients in both groups incurred very high estimated health services costs, the average annual cost during 1983-85 for team cases was 13.6 percent less than that of individual model cases. While the team cases were 18.3 percent less expensive among "old" patients (patients who entered the study from the existing ACCESS caseload), they were only 2.7 percent less costly among "new" cases. The lower costs were due to reductions in hospital days and home care. Team cases averaged 26 percent fewer hospital days per year and 17 percent fewer home health aide hours. Nursing home use was 48 percent higher for the team group than for the individual model group. Mortality was almost exactly the same for both groups during the first year (about 30 percent), but was lower for team patients during the second year (11 percent as compared to 16 percent). Probable mechanisms for the observed results are discussed.

Aged↗
PubMed1990

Long QT syndrome. New electrocardiographic characteristics.

The long QT syndrome is electrocardiographically characterized by a prolonged QT interval and by several other, more subtle, ST-T-U wave abnormalities, most of which have not been quantified. To determine the possible usefulness of several new electrocardiographic characteristics in identifying patients with known long QT syndrome, logistic regression models were applied to a data base of seven new, relatively independent, electrocardiographic repolarization variables. These were measured on digitized 12-lead electrocardiograms of 315 normal subjects and 37 patients with the long QT syndrome (members of well-identified long QT syndrome families, QTc greater than 0.44 second, 27% symptomatic), who ranged in age from 17 to 60 years. Electrocardiographic variables that independently differentiated (p less than 0.001) patients with long QT syndrome from normal subjects included quantitative measures of repolarization: early duration, rate, T wave symmetry, late phenomena, and heterogeneity. All selected repolarization variables except the early duration variable were essentially independent of the QTc (r2 less than 0.15), and all contributed significantly to the identification of patients with long QT syndrome. A classification model of five electrocardiographic predictor variables resulted in an estimated sensitivity (95% confidence interval) of 92.6% (81.6-100%) and an estimated specificity (95% confidence interval) of 95.8% (93.6-98.1%). This model performed significantly better than an alternative classification model that was based on the early duration variable as a single predictor variable. The symptomatic status of patients with long QT syndrome could not be predicted by any combination of the electrocardiographic variables in the investigated model.

Adolescent↗
PubMed1988

Murine ovulatory response to ultrasound exposure and its gynecological relevance.

Ultrasonographic assessment of ovarian follicular maturity was reportedly associated with atypically early ovulation in women; related studies reported reduced litter sizes in rats. To confirm these findings, mice which were midway between ovulatory gonadotropin (LH or human chorionic gonadotropin) stimulation and ovulation, were sham- or ultrasound-treated periovarially for 5 min. Exposure was at a spatial average, temporal maximum intensity of 60 W/cm2. Carrier frequency in the pulse was 2.2 MHz, pulse length was 10 microseconds, and pulse repetition frequency was 200 Hz. Spatial average, temporal average intensity was 0.12 W/cm2. At autopsy, ultrasound- and sham-treated groups responded similarly in proportions ovulating and in mean ova ovulated. Combined experiments had a 97% chance of detecting a significant (greater than 1 h) advance in ovulation time, had it occurred. Thus, our adequately sensitive mammalian ovulatory tests revealed no association of ultrasound with decrease in ovum number or acceleration in ovulation time (as reported in humans).

Animals↗
PubMed1988

Testing for the teratogenicity of pulsed ultrasound in mice.

Our replicate of a study by Takabayashi et al. (1981) Effects of pulse-wave ultrasonic irradiation on mouse embryo. Cho-Onpa Igaku (Supersonic Medicine) 8, 286-288 failed to show any effects of exposure in utero of mice to spatial average, temporal maximum intensities of 60 W/cm2. Fetuses were exposed at 8 days post fertilization and assessed at 18 days for fetal weight, resorptions, premature deaths, and malformations. Carrier frequency in the pulse was 2 MHz. Pulse lengths of 10 microseconds and pulse repetition frequencies of 1000 and 200 Hz yielded spatial average, temporal average intensities of 0.6 and 0.1 W/cm2. Total exposure time was 5 min. Our results provide no basis to conclude that conditions relevant to human fetal monitoring will cause developmental, externally visible anomalies in mice exposed as 8-day fetuses.

Animals↗
PubMed1987

How does the team approach to outpatient geriatric evaluation compare with traditional care: a report of a randomized controlled trial.

Although team-oriented geriatric assessment clinics are growing throughout the country, little documentation exists regarding their clinical efficacy, cost-effectiveness, or impact on patient functioning and well-being. This report describes a randomized controlled clinical trial to evaluate the effectiveness of a team-oriented geriatric assessment approach compared to traditional care. One hundred-seventeen subjects 65 years of age and over, meeting eligibility criteria to target frail older persons with changing medical and social needs, were randomly assigned to receive a comprehensive geriatric assessment by a multidisciplinary team (treatment) or by one of a panel of community internists who were reimbursed according to their usual and customary fee (controls). Extensive analysis of baseline information failed to identify any significant differences between groups. Over the 1-year follow-up period, treatment participants experienced 26 hospital admissions and used 670 hospital days compared with 23 admissions and 1113 days for controls (a 39.8% difference). Annual hospital costs averaged $4297 for treatment subjects and $7018 for controls. Overall institutional costs including hospital and nursing home care revealed an average saving of $2189 per person for treatment subjects compared with controls, a 25% reduction. A small proportion of subjects accounted for this difference. No significant differences were noted in patient or caregiver satisfaction with the evaluation process, functional ability, or health status. These findings suggest that team-oriented outpatient geriatric assessment provides a promising way to deliver high-quality, satisfying care to older persons without increasing (and possibly decreasing) health care costs.

Aged↗