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Biomedical subjects

A Fitzpatrick

Publications and source records attributed to A Fitzpatrick.

At least 19 recordsLinked to original sources
PubMed1997

Correlates of performance-based measures of muscle function in the elderly: the Cardiovascular Health Study.

BACKGROUND: It is unknown how much age-related changes in muscle performance represent normal aging versus the effects of chronic disease and life style. We examined the correlates of four performance measures-gait speed, timed chair stands (TCS), grip strength, and maximal inspiratory pressure (MIP)-using baseline data from the Cardiovascular Health Study (CHS), a population-based study of risk factors for heart disease and stroke in persons > or = age 65. METHODS: We analyzed data from the 5,201 CHS participants. Variables were arranged into nine categories: Personal Characteristics, Anthropometry, Physical Condition, Reported Functional Status, Subjective Health, Psychological Factors, Symptoms, Cognitive Status, Habits and Lifestyle, and Prevalent Disease. Independent correlates were identified using stepwise linear regression. RESULTS: The regression models explained 17.7-25.4% of the observed variability. Although age significantly correlated with each measure, it explained little of the variability (< or = 5.7%). Anthropometric features plus physical condition explained 14.0-17.4% of the variability for grip strength and MIP, but 2.8-12.9% of the variability for gait speed and the log of TCS. Subjective health and psychological factors explained 1.8-9.4% of the variability in gait speed and the log of TCS, but < or = 1.2% of the variability in grip strength and MIP. Variables for prevalent disease explained < or = 1.3% of the variability in each measure. CONCLUSIONS: After age 64, age explained little of the variability in muscle performance in a large sample of mostly functionally intact, community-dwelling older persons. Complex measures such as gait speed were more associated with subjective factors than were direct measures of strength. Prevalent disease contributed surprisingly little to muscle performance.

Aging↗
PubMed1993

Commonly used chiral drugs: a survey.

Initial results of a comparative survey of commonly used chiral drugs are presented. The survey considered the differences between drugs used in 1982 with those in use in 1991. Two major conclusions were reached: the use of single isomer chiral drugs had increased from 31.1% in 1982 to 34.3% in 1991 and the proportion of synthetic single isomer chiral drugs available in 1991 was considerably greater than in 1982.

Pharmaceutical Preparations↗
PubMed1993

Age-related trends in cardiovascular morbidity and physical functioning in the elderly: the Cardiovascular Health Study.

OBJECTIVE: To describe relationships between age and sub-clinical cardiovascular disease, manifest chronic disease, and physical functioning and limitations among persons aged 65 years and older, with emphasis on the "oldest old," those 85 years and older. DESIGN: Observational population-based study. SETTING: Four U.S. communities: Forsyth County, North Carolina; Sacramento County, California; Washington County, Maryland; and Pittsburgh, Pennsylvania. PARTICIPANTS: 5,201 men and women aged 65 years and older. MEASUREMENTS: Demographic data; histories of cardiovascular disease (CVD), chronic lung disease, arthritis, diabetes, and hypertension; measures of subclinical disease including arm and ankle blood pressures, internal carotid wall thickness and stenosis, ejection fraction, left ventricular mass, fractional shortening, and diastolic function, electrocardiographic left ventricular hypertrophy and cardiac injury score, forced expiratory flow and volume; functional status including self-reported physical functioning, hearing and sight limitations and health status, and performance-based measures of function. These variables were examined among men and women in three age groups: 65-74 years, 75-84 years, and 85 + years. Subgroups of participants with and without manifest CVD were also examined. MAIN RESULTS: In women, the prevalence of CVD and other chronic conditions increased with age, and the highest rates occurred among those 85 years and older. In men, prevalence rates increased between the two younger groups, but the oldest group had lower than expected rates for coronary heart disease, cerebrovascular disease, hypertension, and chronic lung disease. In contrast, there were strong age-related linear trends in most of the subclinical measures of blood pressure, atherosclerosis and pulmonary function and in virtually all measures of functional status in both gender groups across the age range. There was a particularly marked decline in functional status between the two older age groups. While subclinical disease was greater and functional status was poorer among those with manifest CVD, with few exceptions, age-related trends were not significantly different between the two groups. CONCLUSIONS: Lower than expected prevalence rates of CVD among those aged 85 years and older, particularly among men, in this study of community-dwelling elderly may represent selection bias or a real plateauing in disease prevalence with age. However, subclinical disease appears to increase and functional status to decline across the age range in both men and women regardless of the presence of CVD. The apparent increase in subclinical disease with age indicates potential for CVD prevention after age 65.

Activities of Daily Living↗
PubMed1991

The incidence of malignant vasovagal syndrome in patients with recurrent syncope.

We reviewed 322 patients with recurrent syncope between 1984 and 1988. Investigation included limited intracardiac electrophysiological study in all cases with programmed extra-stimulus studies in 48 cases. In 93 patients (29%), all investigations were normal, (including negative extrastimulus in 30). In the other 229 cases syncope was explained by AV-block (n = 111, 34%), sinus node disease (n = 68, 21%), carotid sinus syndrome (n = 32, 10%) and inducible sustained tachyarrhythmia (n = 18, 6%). Prolonged 60 degrees head-up tilt was performed in 71 out of 93 patients with unexplained syncope, and reproduced vasovagal syncope and presenting symptoms in 53 (75%), or 16% of the whole population reported. These patients were diagnosed as having malignant vasovagal syndrome. Positive tilts were significantly less common in a group of 27 subjects of similar age without a history of syncope (7%), and a random sample of 37 patients with atrioventricular block (n = 16), sick sinus syndrome (n = 18) and inducible tachyarrhythmia (n = 3), (19%, 11% and 0% respectively, P less than 0.01). From this retrospective review it appears, therefore, that tilt testing is a valuable provocative tool for vasovagal syncope and may reduce the number of syncopal patients that remain undiagnosed, although these early observations do not allow an exact appraisal of the sensitivity and specificity of the tilt test.

Arrhythmias, Cardiac↗
PubMed1991

Dual chamber pacing aborts vasovagal syncope induced by head-up 60 degrees tilt.

To determine if pacing might prevent syncope in cardioinhibitory 'Malignant Vasovagal Syndrome' (also known as 'Neurally-Mediated Bradycardia/Hypotension'), a study of dual chamber pacing during head-up 60 degrees tilt was undertaken. Paired invasive tilts were performed in 10 patients who had a history of recurrent syncope, normal routine investigations including electrophysiological study and prior tilt-induced vasovagal syncope. Vasovagal reactions of identical severity were produced by prolonged 60 degrees head-up tilt on consecutive days in seven out of 10 patients. On day 2, without pacing, seven patients had tilt-induced vasovagal reactions and six became syncopal during the reaction. On day 3, with temporary DVI pacing with rate hysteresis, seven patients had tilt-induced vasovagal reactions and 1 patient was syncopal. Syncope was aborted in the other five patients. DVI pacing significantly improved cardiac index (CI) (one +/- 0.2 to 1.6 +/- 0.3 L/min/m2, P less than 0.01) and mean arterial blood pressure (MABP) (30 +/- 11 to 48 +/- 12 mmHg, P less than 0.01) during vasovagal reactions on day 3 compared with day 2. The mean period of time that patients could tolerate in the tilted position after the onset of the tilt-induced vasovagal reaction was significantly prolonged by pacing from 0.9 +/- 1.2 to 3.2 +/- 1.6 min (P less than 0.01). Dual chamber pacing may abort syncope in 85% of patients with cardioinhibitory malignant vasovagal syndrome. Pacing may prolong consciousness sufficiently during a vasovagal reaction to allow injury to be avoided.

Adult↗
PubMed1991

Natural history of sinus node chronotropy in paced patients.

The natural history of chronotropic incompetence is not clear. To assess this, we evaluated corrected sinus node recovery time (cSNRT) and sinus node chronotropy at rest and during exercise in two groups of syncopal patients with sinus node disease. Group A comprised patients with resting bradycardia but normal cSNRT and group B had resting bradycardia and prolonged cSNRT (greater than 1000 ms). An additional two groups (C and D) were studied. Group C comprised patients with complete AV (CAVB) and no evidence of sinus node disease and group D were asymptomatic controls of similar age. At diagnosis, patients with symptomatic bradycardia but normal cSNRT and no evidence of carotid sinus syndrome (group A) had resting bradycardia and impaired peak heart rate (PHR-I) on exercise compared to controls (P less than 0.001 and P less than 0.05, respectively), but no reduction in exercise duration. At follow-up group A patients demonstrated an increase in resting rate that was significantly slower than the controls (P less than 0.01). Peak heart rate (PHR-II) also remained significantly slower (P less than 0.05). There was no difference in exercise duration between groups A and D at follow-up. Group B was further subdivided according to follow-up findings of preservation of atrial activity in seven patients (group B-1) and junctional rhythm without any atrial activity in four patients (group B-2). Retrospective analysis showed no significant difference in resting heart rate at initial examination but group B-2 showed a significantly lower peak heart rate on exercise compared with B-1 (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

How and when to investigate syncope.

Recurrent syncope is a distressing phenomenon and may be very difficult to treat where the cause remains obscure. A methodical approach to investigation will often be fruitful when proper emphasis is given to thorough clinical assessment and simple investigations. Where these are normal, head-up tilt testing will often diagnose 'malignant vasovagal syndrome'.

Electrocardiography↗
PubMed1989

Tilting towards a diagnosis in recurrent unexplained syncope.

71 patients with recurrent syncope which remained unexplained after standard clinical and electrophysiological investigation underwent 60 degree head-up tilt. This procedure reproduced symptoms with vasovagal syncope in 53 (74%), 40 of whom had bradycardia, some with prolonged asystole, during syncope. The other 13 patients had predominant vasodepression with hypotension. Mean time to syncope after tilt was 25 min. Patients with conduction tissue disease and age-matched control subjects had a 15% and 7% incidence of tilt syncope, respectively. Temporary dual-chamber pacing aborted syncope in 85% of subjects, and improved cardiac index and systemic blood pressure during tilt. Long-term results indicate that selected patients may benefit from permanent dual-chamber pacing. Head-up tilt is useful in the investigation of unexplained syncope because symptoms are reproduced in front of a medical witness.

Aged↗
PubMed1980

Pharmacokinetics of vinblastine-loaded platelets utilized in the treatment of platelet-phagocytizing tumors.

Vinblastine-loaded platelets (VLP) have been successfully used in the treatment of idiopathic thrombocytopenic purpura. Three patients with platelet-phagocytizing tumors and thrombocytopenia were treated with VLP. Patient 1 has sustained a response for 11 months. Patient 2 was not evaluable for response because of early death. Patient 3 had a brief partial response. Vinblastine levels were measured by radioimmunoassay in the platelet-rich plasma, platelet-poor plasma, and serum. The pharmacokinetic data obtained on the patients suggest that: (a) the amount of vinblastine bound to platelets in vivo is a function of the platelet-poor plasma vinblastine level and the platelet count; (b) VLP will probably not have any therapeutic advantage, compared with iv vinblastine alone in patients with normal platelet counts; and (c) it appears that delivery of vinblastine was tumor-specific, since the bone marrow serum vinblastine level in patient 2, obtained when the marrow was replaced by tumor cells, was 2.5-fold higher than a simultaneous peripheral blood serum vinblastine level after VLP. Additional studies with VLP appear warranted in patients with platelet-phagocytizing tumors resulting in thrombocytopenia.

Adult↗