Biomedical subjects
Publications and source records attributed to J Chambers.
We present a report of a Gerbode's defect (left ventricular-right atrial communication) resulting from bacterial endocarditis in a 63-year-old man. Also presented is a brief overview of the literature and a possible preoperative echocardiographic diagnostic criterion relating to this unusual condition.
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Super Profiles have been used as alternative methods of characterising the deprivation of an area. Some reports suggest that Super Profiles are as accurate as established indices such as the Townsend score (TS). This was a test of this assertion.A total of 138 696 live born singleton births to Birmingham residents born between 1986 and 1996 (inclusive) were allocated to enumeration districts (EDs) by linkage from the postcode. We allocated the TS of the individual's ED. We allocated a Lifestyle and Target Market (TM) from Super Profiles by linkage to the ED. We examined the gradient between mean birth weight and the 10 Super Profile Lifestyles and compared this to the gradient between 10 Townsend groups and mean birth weight. We repeated this approach using the 40 TMs and 40 Townsend groups. We used both the median income and a census-derived deprivation measure to rank Lifestyles and TMs. The gradient between mean birth weight and area deprivation was linear for Townsend groups but not linear using either Lifestyles or TMs whichever method of ranking Lifestyles or TMs was used. Where Lifestyles or TMs were out of line with their neighbours, the TS of that group mostly explained this. As Super Profiles are generated using nationally representative data, applying the affluence ranking to small areas can lead to inaccuracies, as shown in this data. We conclude that Super Profiles are probably unsuitable as measures of deprivation of small areas.
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We report two cases of primary pulmonary hypertension (PPH) who benefited from oral sildenafil therapy. Both demonstrated a substantial improvement in exercise ability, which has been sustained at 3 and 6 months. Sildenafil acting as a phosphodiesterase 5 inhibitor may have an important role to play in the management of PPH and we believe further study to be of importance.
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The diagnosis and treatment of heart disease in women continues to be one of the greatest challenges facing cardiovascular medicine today. Marked reductions in mortality rates during the past 2 decades did not result in improved outcomes for women. A major rate-limiting step to improving mortality rates for women is early diagnosis and initiation of effective lifesaving therapies for women. In 1999, HCA Healthcare Systems, Inc, Nashville, TN, initiated a coordinated effort among 208 hospitals in 26 states to improve the diagnosis of coronary disease and to target women who should receive aggressive risk factor modification and referral to cardiologists. We describe the initial phases of program development, including employee risk factor screening; citywide health risk assessment; nationwide educational programs for clinicians, staff, and consumers; and a dedicated outcomes assessment program for tracking women at risk for coronary disease. We believe that these efforts provide a venue for optimal care and improved outcomes for women served by HCA facilities.
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A shortened form of the Parental Bonding Instrument (PBI) (Pederson, 1994) was used to examine the relationship between parenting styles and the psychological distress and offending patterns of a group of young male offenders held in custody in Scotland. High levels of psychological distress were linked with low parental care, but there was no association between psychological distress and parental control. Parental care was not a distinguishing factor in offending patterns, although high paternal control was linked with a younger age of first arrest. When interactions of paternal and maternal parenting styles were examined, young offenders who perceived poor parenting (i.e. neglectful parenting or affectionless control) from both parents had the highest levels of psychological distress overall.
Human morality may be thought of as a negative feedback control system in which moral rules are reference values, and moral disapproval, blame, and punishment are forms of negative feedback given for violations of the moral rules. In such a system, if moral agents held each other accountable, moral norms would be enforced effectively. However, even a properly functioning social negative feedback system could not explain acts in which individual agents uphold moral rules in the face of contrary social pressure. Dr. Frances Kelsey, who withheld FDA approval for thalidomide against intense social pressure, is an example of the degree of individual moral autonomy possible in a hostile environment. Such extreme moral autonomy is possible only if there is internal, psychological negative feedback, in addition to external, social feedback. Such a cybernetic model of morality and moral autonomy is consistent with certain aspects of classical ethical theories.
To compare the pressure drop/flow slope with peak and mean pressure drop, effective orifice area and aortic valve resistance for the prediction of symptom-onset we performed resting and dobutamine stress echocardiography in 49 asymptomatic patients with aortic stenosis (peak aortic velocity>2.5 m/s). The end-point was progression to symptoms requiring surgery and patients were followed for a mean 21.2 (5.2) months. A total of 23 (47%) patients progressed to symptoms requiring aortic valve replacement and 26 remained asymptomatic. There was no significant difference in age, gender, fractional shortening or the presence or absence of coronary artery disease between these groups. There were differences in peak aortic velocity (P<0.0001), peak and mean pressure drop (P<0.0001), effective orifice area (P=0.03), aortic valve resistance (P=0.001) and pressure drop/flow slope (P<0.0001). On Cox regression analysis, the pressure drop/flow slope (P<0.0001), peak aortic velocity (P=0.005) and peak pressure gradient (P=0.02) were independent predictors. Mean event-free survival at 2 years for peak velocity >4.0 m/s was 17% and for pressure drop/flow slope >0.10 mmHg/ms(-1) was 20%. Of 13 patients reporting symptoms during dobutamine stress, 10 (77%) developed spontaneous symptoms during follow-up compared with 13 of 36 (36%) with no symptoms (P=0.11). The pressure drop/flow slope is a better independent predictor of symptom onset than resistance, mean pressure difference and effective orifice area, but is similar to peak velocity.
OBJECTIVE: To evaluate changes in left ventricular mass and diastolic function during normal pregnancy. METHODS: This was a cross-sectional study of 125 pregnant women at 9-42 weeks of gestation and 19 non-pregnant female controls. Two-dimensional and M-mode echocardiography of the maternal left ventricle and left atrium was performed. RESULTS: During pregnancy left ventricular mass increased by 52%. There was an increase in left ventricular end-diastolic and end-systolic diameters (12% and 20%, respectively), left ventricular posterior wall diameter during diastole and systole (22% and 13%, respectively) and left intraventricular septum during diastole and systole (15% and 19%, respectively). Mitral valve A-wave maximum velocity increased during pregnancy by 19%, while mitral valve E-wave maximum velocity and the ratio of E-wave/A-wave velocities increased early in pregnancy by about 14% and 6%, respectively, with a subsequent decline to 4% and 10%, respectively, below non-pregnant levels. CONCLUSION: Left ventricular mass increases during pregnancy, while left ventricular diastolic function, as demonstrated by the changes in mitral valve flow velocities, increases in the first two trimesters but declines in the third trimester.
OBJECTIVES: Circumferential fiber shortening has been the dominant basis for conventional analysis by echocardiography of left ventricular systolic function during pregnancy. Results in the literature have been conflicting due mainly to the fact that geometric assumptions for the calculation of these indices are made that may not be valid due to changes in left ventricular shape during pregnancy. Left ventricular long-axis displacement is expected to be a useful index of systolic function, independent of the changes in left ventricular geometry. The aim of this study was to compare circumferential to long-axis shortening during left ventricular contraction in pregnant women. METHODS: This was a cross-sectional study of 125 pregnant women at 9-42 weeks of gestation and 19 non-pregnant female controls. Two-dimensional and M-mode echocardiography of the left ventricle was performed including measurement of left ventricular long-axis displacement and activation time on the lateral, septal, anterior and inferior sides of the mitral annulus. Activation time was assessed as the time from the start of the Q-wave of the electrocardiogram to the onset of left ventricular long-axis shortening. RESULTS: Mean arterial pressure and activation time decreased during pregnancy, reaching a nadir at about 19 weeks' gestational age of 4% and 13%, respectively, below non-pregnant values; they subsequently increased towards term. Left ventricular long-axis displacement mirrored the changes in mean arterial pressure and activation time and increased with gestational age at all four sites of the atrioventricular plane reaching a peak at about 23 weeks (+ 12% compared to non-pregnant levels). The ejection fraction and fractional shortening remained stable until 30 and 32 weeks, respectively, and then decreased towards term. CONCLUSION: Changes in left ventricular long-axis performance during pregnancy occur earlier than do measures of transverse function.
Functional magnetic resonance imaging (fMRI) provides a noninvasive tool for observing correlates of neural activity in the brain while a subject listens to sound. However, intense acoustic noise is generated in the process of capturing MR images. This noise stimulates the auditory nervous system, limiting the dynamic range available for displaying stimulus-driven activity. The noise is potentially damaging to hearing and is distracting for the subject. In an active noise control (ANC) system, a reference sample of a noise is processed to form a sound which adds destructively with the noise at the listener's ear. We describe an implementation of ANC in the electromagnetically hostile and physically compact MRI scanning environment. First, a prototype system was evaluated psychoacoustically in the laboratory, using the electrical drive to a noise-generating loudspeaker as the reference. This system produced 10-20 dB of subjective noise-reduction between 250 Hz and 1 kHz, and smaller amounts at higher frequencies. The system was modified to operate in a real MR scanner where the reference was obtained by recording the acoustic scanner noise. Objective reduction by 30-40 dB of the most intense component in scanner noises was realized between 500 Hz and 3500 Hz, and subjective reduction of 12 dB and 5 dB in tests at frequencies of 600 Hz and at 1.9 kHz, respectively. Although the benefit of ANC is limited by transmission paths to the cochlea other than air-conduction routes from the auditory meatus, ANC achieves worthwhile attenuation even in the frequency range of maximum bone conduction (1.5-2 kHz). ANC should, therefore, be generally useful during auditory fMRI.
OBJECTIVES: To compare cardiac troponin T, myoglobin, CK, CKMB activity, CKMB mass and the initial electrocardiogram in the early diagnosis of myocardial infarction in the emergency department. Methods-Biochemical markers were measured at presentation in patients with a possible diagnosis of acute myocardial infarction. Based on the clinical notes, patients were grouped as "definite myocardial infarction" (n = 50), "definite no myocardial infarction" (n = 81) and "uncertain" (n = 96). Sensitivity and specificity and positive and negative predictive values were calculated using the 131 patients with definitely present or absent myocardial infarction. RESULTS: The initial electrocardiogram was more sensitive than any of the markers in the first six hours from symptom onset-sensitivity 74% (95%CI 61% to 88%). The positive predictive value of the initial electrocardiogram was 97% in the first six hours; the markers ranged from 47% to 67%. The negative predictive value of the initial electrocardiogram was 85% in the first six hours; the markers ranged from 61% to 70%. Four patients with non-diagnostic electrocardiograms presenting beyond six hours after pain onset had a myocardial infarct detected by at least three of the biochemical markers in each case. CONCLUSIONS: The electrocardiogram is of more diagnostic use than biochemical markers in the first six hours after the onset of pain, but biochemical markers give additional positive diagnostic information in patients presenting later than this. The negative predictive accuracy of biochemical markers is too low for a single sample to be useful for excluding myocardial infarction in the first six hours after onset of symptoms.
OBJECTIVES: To examine long axis excursion in patients with all grades of aortic stenosis and preserved transverse systolic function, and to compare long axis excursion in symptomatic with that in asymptomatic severe aortic stenosis. DESIGN: Prospective comparative study. SETTING: Regional cardiothoracic centre. PATIENTS: 78 patients with all grades of aortic stenosis and normal fractional shortening and ejection fraction were studied. There were two comparison groups, 10 age matched normal subjects and 14 patients with aortic stenosis and fractional shortening < 26%. METHODS: Aortic valve function and left ventricular mass were assessed echocardiographically. M mode measurements of long axis excursion at the septal and lateral sides of the mitral annulus were taken. RESULTS: There were significant differences between the groups in long axis excursion at both the septal (p < 0.0001) and lateral sides of the mitral annulus (p = 0.002 by analysis of variance). Long axis excursion was independently related to both left ventricular mass index (p = 0.001) and the grade of aortic stenosis (p = 0.002). Comparing patients with severe aortic stenosis with and without symptoms, there were significant differences in effective orifice area (p = 0.02 ) and long axis excursion at the lateral side of the mitral annulus (p = 0.04), but not in fractional shortening, ejection fraction, or peak or mean pressure difference. CONCLUSION: In patients with aortic stenosis, long axis excursion is reduced even in the presence of normal fractional shortening or ejection fraction. It is lower in patients with symptomatic compared with asymptomatic severe aortic stenosis and may be of use in predicting the onset of symptoms.
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