Detecting severe silent mitral regurgitation.
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Echocardiography↗
Biomedical subjects
P Mills
Publications and source records attributed to P Mills.
Does reactivity testing in the laboratory reflect blood pressure changes elsewhere?
This study examines whether reactivity testing in a laboratory setting might identify individuals whose blood pressure (BP) fluctuates excessively outside of the laboratory. Eighty-eight normotensive and untreated hypertensive patients were studied. Patients' BPs were obtained repeatedly on two separate screening occasions. They were subsequently admitted to a research ward, and 4 days later their BPs were measured at resting baseline and in response to a series of stressful tasks. Blood pressure declined by 14/11 mm Hg +/- 1.2/1.1 mm Hg (SE) from screening to the in-patient resting baseline. The four stressful tasks all led to increases in BP over the in-patient resting baseline level. Individuals with increased amounts of task-induced reactivity in the laboratory were also more likely to be those whose BP declined the most from out-patient screening to hospitalized baseline. The average correlation between the drop in BP associated with hospitalization and the BP reactivity to each stressor task was r = 0.33 for systolic BP (p < 0.01) and r = 0.24 for diastolic BP (p < 0.05). Reactivity responses in a laboratory setting may convey information about blood pressure fluctuation in the real world.
Adult↗
Chromogranin A correlates with norepinephrine release rate.
Chromogranin A (CgA) is an acidic protein co-released with catecholamines during exocytosis from sympathetic nerve terminals and chromaffin cells. Previous work has demonstrated that large scale perturbations in sympathetic nervous system (SNS) functioning result in corresponding changes in CgA levels in plasma. Little is known about the physiologic significance of CgA. We hypothesized that, since CgA and catecholamines are co-released from the same storage vesicles, and since CgA is not subject to reuptake or enzymatic metabolism, plasma CgA should reflect norepinephrine release from sympathetic terminals. We therefore measured venous CgA, norepinephrine levels, and norepinephrine release rate in 30 unmedicated subjects. Although the correlation of CgA with plasma norepinephrine was only modest (r = 0.37, p less than 0.05), its correlation with norepinephrine release rate was highly significant (r = 0.58, p less than 0.001). Thus, CgA may offer a novel perspective on peripheral sympathetic activity.
Adult↗
Young infarct patients with single-vessel occlusion do not have an underlying prothrombotic state to explain their coronary occlusion.
To determine the importance of a prothrombotic state in the pathogenesis of coronary occlusion in young infarct patients, assessment of risk factor profile and thrombotic tendency was undertaken in 25 young male patients (age less than 45 yr) who were shown at angiography, following myocardial infarction, to have occlusion of a single coronary. Comparison was made with a control group of symptomatic males aged greater than 55 yr, who at angiography had significant disease in two or more coronary arteries (multi-vessel disease control group). At the time of the study more patients in the single-vessel disease study group smoked cigarettes (n = 12) compared to the control group (n = 5) (p less than 0.01). Serum cholesterol and triglycerides were higher, and high density lipoprotein-cholesterol lower, in the single-vessel disease group but the difference reached significance only with the high density lipoprotein-cholesterol. Quantitative platelet aggregability was similar in the two groups. Although the level of beta-thromboglobulin, was higher in the single-vessel disease study group the difference was not significant. There were also no significant differences between these groups in levels of fibrinogen, Factor XII and alpha-2 antiplasmin. Patients in the multi-vessel disease group, however, had increased Factor VII levels (p less than 0.01). There were no significant differences between the two groups in fibrinolytic potential or in levels of antithrombin III. Coronary occlusion in the young appears likely to be due primarily to an arterial (plaque) related event as opposed to an abnormal coagulation response to minor arterial plaque damage.
Adult↗
Influence of pressure supports on joint range of motion.
Burn patients often complain of restricted mobility following application of elasticized nylon anti-burn-scar supports. This study was designed to analyse the influence of this type of pressure garment on joint range of motion (ROM). Data were compiled from 80 burn-affected joints of 17 burn patients placed in a support for the first time. Joint ROM was measured directly prior to, and again immediately following, the donning of the pressure support. ROM was measured using standard goniometric techniques. Range of motion increased in 26 joints (32.5 per cent), decreased in 26 joints (32.5 per cent) and showed no change in 28 joints (35 per cent) after application of the pressure garment. There were no correlations between ROM results and age, time postburn and per cent TBSA in this population. Patients were also asked if movement felt any different after the support was applied. Their varied comments, such as movement felt easier or more difficult, were consistent with the actual ROM data. It appears that there is no predictably detrimental change in joint ROM due to the application of pressure garments.
Adult↗
Analysis of set screw and side-lock connector reliability.
A retrospective review of complications with connectors and lead-to-header interfaces was performed following 649 pacing procedures between 1980 and 1990. There were 88 lead revisions (13.6%), 81 device replacements or modifications (12.5%), and 480 new implants (74%) using devices of five manufacturers. Two basic connector types were studied, one utilizing a set screw and the other using a side-lock compression fitting. The set screw makes electrical contact and mechanically secures the lead connector pin with a set screw insulated by a self-sealing grommet or an integral or separate set screw cover. The side-lock makes electrical contact with an automatic spring mechanism while the plastic lead terminal is secured in the connector block of the pacemaker by a Delrin side-lock compression fitting. Four hundred fifty-nine set screw connector devices were followed for up to 12 years with 14 complications (3.1%) whereas 82 side-lock connector devices were followed for up to 5 years with one complication (1.2%). The set screw and side-lock connectors were reliable over the period of follow-up. Although the complication rate appeared lower with the side-lock, follow-up was shorter and the number of implants smaller. With the leads used in this study, the side-lock proved to be a desirable feature due to simplicity, speed, safety, and ease of use. One limitation is the requirement for a precise IS-1 connector terminal diameter.
Electrodes, Implanted↗
Diagnostic techniques in suspected thoracic aortic dissection.
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Aortic Dissection↗
Converting enzyme inhibition and blood pressure reactivity to psychological stressors.
There is considerable interest in blood pressure reactivity to psychological stressors. Because the sympathetic nervous system and the renin-angiotensin system are so responsive to stressors and are themselves the targets of many antihypertensive medications, many investigators have wondered if such medications decrease the blood pressure response to stressful stimuli. We studied 25 normotensive and 21 hypertensive men in a double-blind crossover study during which they received either placebo for 4 days or captopril (25 mg b.i.d.) for 4 days while they were hospitalized in a clinical research center. Patients were studied at resting baseline, while performing a mathematics task, and while reading out loud a disturbing newspaper article. Although captopril lowered the resting blood pressure levels, it had no effect on the amplitude of reactivity to stressors.
Angiotensin-Converting Enzyme Inhibitors↗
Psychosocial correlates of reactivity in black and white men.
This study sought to clarify the relationship between cardiovascular reactivity, hostility, depression and ethnicity. Blood pressure and heart rate responses to a standard arithmetic stressor were analyzed in 97 unmedicated hypertensive and normotensive men. Hypertensives and normotensives showed similar increases from baseline on systolic and diastolic blood pressure and on heart rate. Among whites (N = 44), systolic and diastolic reactivity were related to lower scores on the Verbal subscale items of the Buss-Durkee Hostility Inventory (p less than 0.05, for both). Among blacks (N = 53), no such relationship was found. Heart rate reactivity was related to greater depression scores among whites (p less than 0.01), but not among blacks. Among black subjects, heart rate increases were related to higher scores on the Indirect Anger subscale items of the Buss-Durkee (p less than 0.05). These results suggest that the expression of emotion and reactivity to a psychosocial stressor may be socioculturally mediated.
Adolescent↗
Technical report: percutaneous treatment of a pancreatic duct fistula facilitated by an hydrophilic guide wire.
A case in which a pancreatico-cutaneous fistula was successfully treated percutaneously is presented. The use of an hydrophilic guide wire enabled a catheter to be negotiated across an irregular abscess cavity and into the occluded main pancreatic duct. The low friction and good flexibility of hydrophilic guide wires can greatly facilitate difficult procedures.
Catheterization↗
Hypertensives' pressor response to norepinephrine. Analysis by infusion rate and plasma levels.
After 5 days of a 10 mEq sodium diet or 4 days of a 200 mEq sodium diet, 15 hypertensives and 11 normotensive control subjects received pressor doses of intravenous norepinephrine (NE). Analysis of pressor responses to the rate of NE infusion showed that the high salt diet sensitized subjects so that they needed less NE to raise systolic blood pressure (SBP) 20 mm Hg (P = .005). There was a complex interaction of salt intake, black race, and hypertension on NE pressor sensitivity (P = .03). Hypertensives attained lower plasma NE levels during the stepwise NE infusion, so we reanalyzed NE sensitivity in terms of the changes in plasma NE levels. This analysis also showed that during the high salt diet, subjects initiated a pressor response at lower plasma NE levels (P = .017) and raised SBP 20 mm Hg at lower NE levels (P = .007). The reanalysis showed that hypertensives initiated a pressor response at lower plasma NE levels (P = .03) and raised SBP 20 mm Hg at lower NE levels (P = .002). Plasma NE levels should provide a better guide to the concentration of NE at cardiovascular receptors than the rate of NE infusion. Analysis of pressor responses to plasma NE levels demonstrated that the hypertensives had an exaggerated pressor response to NE.
Black People↗
Influence of altered phospholipid composition of the membrane outer layer on red blood cell aggregation: relation to shape changes and glycocalyx structure.
Reversible aggregation of erythrocytes was investigated after alteration of the phospholipid content in the membrane outer leaflet either by disturbance of endogenous transmembrane lipid asymmetry through changes in cellular free calcium, or by incorporation of exogenous lyso-derivatives. It was found that both calcium loading and lyso-phosphatidylcholine (LPC) addition induce a strong increase in red cell-red cell adhesive energy, whereas lyso-phosphatidylserine (LPS), added in the same amount as LPC, does not. Red cell morphological studies show differences in the shape change efficiency of LPS, LPC and calcium loading. However, it was further demonstrated that shape change is not directly responsible for the observed adhesive energy increase, since neuraminidase or trypsin treatment abolish this increase, even though the shape changes induced by alteration of phospholipid organization are not affected. The latter experiment strongly suggests that the red cell adhesive energy increase results from an alteration of the glycocalyx structure, which could be in turn a consequence of the shape change.
Calcium↗
Ultrasound in the diagnosis of granulomatous liver disease.
Ultrasound is a widely used method of assessing the liver for space occupying lesions and, more recently, parenchymal liver disease. We have reviewed the ultrasound scans and reports of 11 patients with biopsy proven granulomatous liver disease. Multiple echogenic lesions 3-5 mm in diameter, each surrounded by an hypoechoic halo, were seen in the liver of all the patients and in the spleens of three patients. A specific diagnosis of granulomatous hepatitis was suggested at the time of scanning in seven patients. An abnormal liver was noted in the other four patients but no specific diagnosis was suggested. We believe that granulomata in the liver can be detected using ultrasound and, if the above appearances are seen during an ultrasound scan, a diagnosis of granulomatous hepatitis should be considered.
Adult↗
Prediction of salt sensitivity.
The overall prevalence of salt sensitivity was studied in 75 men stratified by diagnosis (hypertensive v normotensive) and race (black v white). All were studied in a crossover design employing a 200 mEq and 10 mEq Na/day. High salt led to a decrease in diastolic pressure for all groups (P less than .002). For systolic pressure, there was no salt effect on blood pressure across the whole group; however amongst the hypertensives, particularly the black hypertensives, high salt led to increases in systolic pressure (P less than .022). Obese patients were more likely to increase their systolic pressure in response to salt loading (P less than .05). The patients whose pressure increased on high salt were those who manifested less of a decrease in plasma levels of norepinephrine and renin in response to salt loading (both P less than .05). Systolic salt sensitivity was predicted with high statistical power (R = 0.689, P less than .00001) by a multiple regression equation employing: race; diagnosis; the change in renin and norepinephrine levels with diet; and the change in BP sensitivity to infused norepinephrine across the two diets. In view of the findings of increased norepinephrine, renin and diastolic pressure on low salt and in view of the particular physiological and epidemiological setting associated with systolic salt sensitivity, one wonders about the advisability of across-the-board recommendations of low salt diets for all hypertensive patients.
Adult↗
Should coronary angiography be performed in district hospitals?
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Cardiac Catheterization↗
Identification of a high risk subgroup of patients with silent ischaemia after myocardial infarction: a group for early therapeutic revascularisation?
Asymptomatic ("silent") ischaemia has been shown to be of prognostic significance in patients with stable and unstable angina and more recently in patients recovering after myocardial infarction. No therapeutic regimen has yet been shown to improve the prognosis of patients with silent ischaemia after infarction, which can be found in as many as a third of these patients. Attempts to achieve therapeutic revascularisation in all these patients may be undesirable, but early revascularisation could be especially beneficial in some selected high risk patients. Two hundred and fifty consecutive clinically stable survivors of myocardial infarction who had predischarge submaximal exercise tests were followed up for a year. Silent ischaemia was found in 27% of these patients; 15% had symptomatic ischaemia. Patients with a positive exercise test were prescribed a beta blocker before discharge. Mortality in patients with silent (9.4%) and symptomatic (5.4%) ischaemia in the first year after infarction was not significantly different. Patients with symptomatic ischaemia were more likely to have undergone coronary artery bypass grafting in the first year. Patients with silent ischaemia were, however, significantly more likely to die than patients with a negative exercise test (relative odds 12:1). Patients with silent ischaemia and an abnormal blood pressure response or who could not complete a submaximal exercise protocol were at particularly high risk, being 32 times more likely to die than those with a negative test (95% confidence interval from 3.3 to 307 times more likely). First year mortality in this group was 22%. The benefits of therapeutic revascularisation in this high risk group need to be studied.
Coronary Angiography↗
Effects of salt, race, and hypertension on reactivity to stressors.
Blood pressure and heart rate reactivity to a psychological stressor and to a cold pressor test were examined in a group of 51 normotensive and 37 unmedicated hypertensive men. All were studied twice, once while the participants were maintained on a moderately high salt (200 meq sodium/day) diet and once while the participants were maintained on an extremely low salt (10 meq sodium/day) diet. Dietary salt had no effect on blood pressure or heart rate responses to the two stressors. The systolic and diastolic responses of the white participants to the psychological stressor were greater than those of the black participants (both p less than 0.05); however, there was no difference between blacks and whites in reactivity to the cold pressor challenge. As compared with the normotensive group, the hypertensive group reacted to the psychological stressor with increased responses in systolic blood pressure, diastolic blood pressure, and heart rate (all p less than 0.05). The hypertensive group also hyperresponded in terms of the systolic pressure response to the cold pressor task (p less than 0.05). Plasma norepinephrine and epinephrine responses were not significantly different across the two diets, races, or diagnoses.
Adult↗
Beta-adrenergic receptor sensitivity during sodium restriction and converting enzyme inhibition.
Adding converting-enzyme inhibitors to the salt depleted state is marked by a reduction in blood pressure despite compensatory increases in heart rate and plasma norepinephrine. This study investigated whether this increase in sympathetic function is also accompanied by an increase in beta-adrenergic receptor function. Ten subjects were studied following two separate five day hospitalizations on 10 mEq sodium diets while receiving either placebo or captopril. During low sodium with captopril, blood pressure and angiotensin II decreased, while heart rate, renin, norepinephrine and isoproterenol-stimulated cyclic AMP accumulation in lymphocytes increased. The results indicate that enhanced beta-adrenergic receptor function does accompany sympathetic activation during sodium restriction and converting enzyme inhibition and further support studies showing that the renin-angiotensin system plays the dominant role in blood pressure regulation in the sodium depleted state.
Adult↗