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Biomedical subjects

E B Raftery

Publications and source records attributed to E B Raftery.

At least 19 recordsLinked to original sources

Right atrial thrombus migration during echocardiography: a case for urgent intervention.

A 65-year-old woman presented with increasing shortness of breath, chest pain and ST-T wave abnormalities on the electrocardiogram suggestive of unstable angina. Cross-sectional echocardiography performed to assess wall-motion abnormality and left ventricular function revealed a pedunculated right atrial thrombus prolapsing into the right ventricle which suddenly dislodged and migrated into the pulmonary circulation during the examination. A diagnosis of recurrent pulmonary thromboembolism was made, necessitating urgent pulmonary angiography with infusion of streptokinase. The patient made an uneventful recovery.

Aged

Improvement in left ventricular function after rapid weight loss in obesity.

The effect of rapid weight reduction on left ventricular function and blood pressure was studied in 34 obese subjects, who all weighed more than 30% above their ideal body weight. Subjects with co-existing hypertension (N = 15) and proven coronary artery disease (N = 9) were included to assess contributions from these factors. Blood pressure (BP) was measured both indirectly and by direct ambulatory intra-arterial methods. Radionuclide ventriculography was performed at rest and at exercise, before and after dieting, which was supervised in hospital (daily intake 330 kCal day-1 for 4 weeks). Dieting induced a weight loss of (mean +/- SD) 9.6 +/- 3.5 kg (P less than 0.0001) in the whole group. The mean daytime intra-arterial blood pressure fell from 157 +/- 23/90 +/- 15 to 144 +/- 21/85 +/- 13 mmHg (P less than 0.0001). The fall in ambulatory intra-arterial diastolic blood pressure did not reach significance in the normotensive and ischaemic groups. The mean resting left ventricular ejection fraction (LVEF) in the whole group showed a significant reduction after weight loss from 61 +/- 10% to 56 +/- 6% (P less than 0.005). Although the individual groups showed a fall in LVEF, the effect was most marked in the hypertensive group, from 65 +/- 9% to 57 +/- 5% (P less than 0.002). Before dieting none of the groups achieved a 'normal' 5% rise in LVEF above basal in response to exercise, the hypertensive and the ischaemic groups both showing non-significant falls. This phenomenon was, however, reversed after weight loss.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Blood pressure changes during the game of squash.

The extent and pattern of the blood pressure response to the playing of squash was studied in five healthy volunteers using intra-arterial blood pressure recordings. Systolic pressure increased more than diastolic, but by only 18% of basal, peaking 5.2 +/- 2.3 min into the game (mean game duration 49 +/- 4 min). Thereafter there was a progressive decline, with reducing pulse pressure towards basal. There was a marked and significant increase in beat-by-beat blood pressure variability (P less than 0.01) and systolic peaks of up to 200 mmHg were recorded. A peak heart rate of 171 +/- 25 beats min-1 occurred at 20 min. These findings do not support the concept of a disproportionate and prolonged pressor response induced by playing squash. The possibility of high single-beat systolic peaks still justifies some caution in subjects at risk of arterial rupture.

Adolescent

Spontaneous variability of left ventricular ejection fraction assessed with the Cardioscint.

A miniature, non-imaging caesium iodide nuclear probe optically coupled to a photodiode (the 'Cardioscint') has been developed which, in conjunction with a modified personal computer, is capable of continuous on-line monitoring of left ventricular function and ST-segment level at the bedside. The purpose of this study was to assess the variability in ejection fraction over periods of time and to compare this variability with that of equilibrium gamma camera radionuclide ventriculography. Ten normal volunteers (nine male) of mean (S.D.) age 49 (10) years underwent semisupine radionuclide ventriculography using both gamma camera and Cardioscint in randomized order. The gamma camera recorded four consecutive acquisitions (mean of 7.2 min each) and the Cardioscint, using a 20 s acquisition time, recorded left ventricular function over 35 min per subject. The mean ejection fraction of the group by gamma camera was 52 (7)% and by Cardioscint was 54 (5)%. When the variability in ejection fraction by gamma camera was compared with the Cardioscint averaged over corresponding time periods (i.e. an average of 7.2 min), the mean coefficient of variation of the camera was 5.0% versus 2.9% for the probe system. Individual 20-s probe acquisitions over the total study duration (reflecting the short-term variability of the system) had a coefficient of variation of 5.1%. Thus the Cardioscint provides a stable continuous recording of ejection fraction. These volunteer data provide a basis for interpretation of data acquired in the clinical situation.

Adult

Intra-arterial monitoring of the antihypertensive effects of once-daily amlodipine.

Amlodipine is a dihydropyridine calcium antagonist with a long elimination half life making it suitable for once-daily dosing. This study used sphygmomanometric and intra-arterial ambulatory blood pressure (BP) monitoring to confirm the antihypertensive effect of a once-daily dose of amlodipine over the dosing interval. After a 2-week single-blind placebo run in, amlodipine was administered to 11 patients at a starting dose of 5 mg daily for 2 weeks increasing to 10 mg daily for a further 4 weeks if diastolic blood pressure (DBP) measured sphygmomanometrically was not < 90 mmHg or decreased by > 10 mmHg from baseline values. Intra-arterial blood pressure recordings for 24-hour periods were made at the end of the placebo run in and on completion of the active treatment phase. The effects of isometric and dynamic exercise and head-up tilting (60 degrees) on BP and heart rate were measured during ambulatory monitoring. Mean supine cuff BP was 169/104 mmHg (n = 11) at the end of the placebo treatment period and was reduced to 153/95 mmHg (n = 11) after 2 weeks of amlodipine treatment and 146/92 mmHg (n = 11) after 6 weeks of amlodipine treatment. There was no significant change in heart rate. Intra-arterial ambulatory monitoring showed that BP was controlled for the whole dosing interval with once-daily doses of amlodipine. The normal circadian pattern of BP changes was not altered. BP was reduced by amlodipine during exercise and physiological tests, but there was no postural hypotension and the BP and heart rate responses to exercise were not blunted.(ABSTRACT TRUNCATED AT 250 WORDS)

Amlodipine

Myocardial infarction associated with exercise in young men.

Three male patients age 17, 23 and 27 years developed chest pain during, or in one case, immediately after competitive sport. In all cases myocardial infarction was diagnosed by standard criteria or the diagnosis was made on the basis of indium-111 antimyosin imaging, contrast ventriculogram and thallium scan. Coronary arteriography was normal in two and a blocked right coronary artery was found in one. Exercise-related myocardial infarction can occur in young men and chest pain during exercise in this age-group may not always be innocent.

Adolescent

Prolonged hypotensive effect of OPC-13340: a new, once-daily calcium channel blocking drug.

The duration and magnitude of the hypotensive effect of a new, once daily dihydropyridine calcium channel blocking drug, OPC-13340, was assessed in 14 patients with essential hypertension during normal daily activities and programmed exercise testing. Intra-arterial ambulatory blood pressure (BP) monitoring was performed before and after one month's treatment. Mean reduction in day-time BP was 27/14 mmHg and night-time BP 18/11 mmHg (P less than 0.001 and 0.05 respectively). There was no change in heart rate throughout the 24 h. Satisfactory day-time control of systolic and diastolic BP using the drug as monotherapy was achieved in 58% and 88% of patients respectively, although adequate control of nocturnal systolic and diastolic BP occurred in only 54% and 50% of patients respectively. No postural hypotension occurred during tilt testing, and there was a significant reduction in the peak BP observed during both dynamic and isometric exercise. Side effects were mild and transient. Thus OPC-13340, given once daily, is an effective and well tolerated anti-hypertensive drug, with a prolonged 24-h action.

Adult

Circadian variation and blood pressure: response to rapid weight loss by hypocaloric hyponatraemic diet in obesity.

Ambulatory intra-arterial blood pressure was monitored in 15 obese hypertensive and 10 obese normotensive subjects weighing more than 30% of their ideal body weight. Measurements were taken before and after 1 month in hospital on a diet of 330kCal/day designed to ensure 34 g protein and 65 mmol sodium. Mean +/- s.d. body mass index in the whole group fell from 40.8 +/- 7.6 to 37.2 +/- 7.4 kg/m2 (P less than 0.0001). Daytime intra-arterial blood pressure fell from 176 +/- 19/102 +/- 14 to 162 +/- 16/95 +/- 14 mmHg (P less than 0.0005 and P less than 0.002) in the hypertensive group and from 141 +/- 15/82 +/- 5 to 131 +/- 13/79 +/- 4 mmHg (P less than 0.005 for systolic pressure) in the normotensive group. Circadian variation of systolic intra-arterial blood pressure comparing the mean daytime with the mean night-time blood pressure recordings showed a day-night difference of 27 +/- 10 mmHg in the normotensive group compared with 12 +/- 13 mmHg in the hypertensive group (P less than 0.01). This trend was reversed after weight loss, when the normotensive group showed a day-night difference of 20 +/- 13 mmHg compared with 18 +/- 17 mmHg in the hypertensive group. Thus, circadian variation of systolic intra-arterial blood pressure in the hypertensive group was significantly (P less than 0.01) reduced compared with the normotensive group prior to, but not after, weight loss. These data show that, in obese subjects, weight loss produced a significant reduction in ambulatory intra-arterial blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Twenty-four-hour blood pressure control: an intraarterial review.

Intraarterial blood pressure monitoring has shown the circadian rhythm of blood pressure control. Blood pressures tend to be highest in the morning before falling gradually during the day to a nadir at 3:00 a.m. There is a slight rise in the late afternoon that may correspond to patients' attendance at hospital for calibration of the equipment. There is a small rise in the blood pressure before awakening, and after arousal there is a rise in blood pressure to the peak level of the morning. In this article, we examine the effect of a variety of antihypertensive agents on this rhythm. In general, beta-adrenoceptor blockers appear to have less effect on nocturnal blood pressure and surge in pressure after arousal, while vasodilators, particularly alpha-adrenoceptor blockers, have a pronounced effect. These findings indicate that the rise in blood pressure before awakening and the rapid rise upon arousal appear to be due to increased alpha-adrenoceptor activity.

Antihypertensive Agents

Lacidipine and circadian variation in blood pressure: considerations for therapy.

The circadian rhythm of blood pressure has been shown to be an accurate and repeatable method of characterizing blood pressure over each 24-h period, and probably provides the best index of cardiovascular risk. Many studies have confirmed that these curves can be used to define accurately the duration and degree of antihypertensive effect of drugs, and are not influenced by the administration of placebo. Furthermore, these curves represent an ideal method for testing the efficacy of once-daily drugs. Lacidipine has been tested against these curves in 12 hypertensive patients, and has been shown to be an effective antihypertensive agent throughout the day, with a 24-h duration of action after a single oral dose and without reflex tachycardia.

Blood Pressure

Direct versus indirect measurement of blood pressure.

The indirect method of blood pressure measurement is known to be potentially inaccurate, slow-moving and incapable of recognizing artefacts such as the 'alerting reaction'. This situation can be improved by repeated measurements, with, for example, ambulatory non-invasive measurement. Nevertheless, these clinic blood pressure measurements are known to supply very good prognostic information, at least in large populations, and it has yet to be established that ambulatory monitoring can supply better prognostic data. The direct technique, in contrast, is of known and measurable accuracy, records every pressure pulse and can recognize all artefacts. Unfortunately, the direct technique has no general clinical application because of its invasive nature, and there is a need to break with conventional thinking and develop a new technique that can match the direct technique without the need for physiological invasion.

Artifacts

Circadian variation in blood pressure: considerations for therapy.

Accurate measurement of blood pressure is a primary requirement of studies in hypertension and its treatment. However, this is not an easy objective to achieve with sphygmomanometric methods of measurement. Intra-arterial monitoring is an objective method of blood pressure measurement that has become popular in studies of hypertension since its introduction in the 1960s. Since that time the technique has been used to characterize the now well-accepted physiological variability in blood pressure. The clinical significance of such observations is still the subject of active debate. However, it seems clear that, as blood pressure rises sharply in the morning and this occurs at around the same time as the peak incidence of serious cardiovascular events, antihypertensive therapy should control blood pressure effectively at this time. This article summarizes results from some studies, using intra-arterial blood pressure monitoring to indicate the importance of blood pressure variation, 24-h blood pressure control and experience with antihypertensive drugs of various pharmacological classes.

Amlodipine

Effectiveness of the once-daily calcium antagonist, lacidipine, in controlling 24-hour ambulatory blood pressure.

The efficacy of the new once-daily dihydropyridine calcium antagonist, lacidipine, in reducing ambulatory intraarterial blood pressure (BP) was examined in 12 untreated hypertensive patients. The intraarterial recording was commenced 24 hours before the first 4-mg dose and was continued for a further 24 hours thereafter. After dose titration and chronic therapy, a second 24-hour ambulatory BP recording was made. There was a steady onset of drug action, maximal at 2 hours, but with reflex tachycardia after the first dose. Chronic administration reduced BP throughout the 24-hour period, without tachycardia. Mean daytime reduction in BP was 20 mm Hg systolic (p less than 0.005) and 12 mm Hg diastolic (p less than 0.02). Mean nighttime reduction was 8-mm Hg systolic (p less than 0.05) and 6-mm Hg diastolic (difference not significant). There was no postural decrease in BP on 60 degrees head-up tilting and hypotensive action was maintained during isometric exercise (reduction at peak of 32/18 mm Hg, p less than 0.05) and throughout dynamic exercise (reduction at peak of 23/14 mm Hg, p less than 0.05). Lacidipine is an effective once-daily antihypertensive agent, with good control of stress response.

Blood Pressure

Value of carvedilol in congestive heart failure secondary to coronary artery disease.

Despite considerable interest in the use of beta-blocking agents in congestive heart failure (CHF), their clinical application is limited because of their negative inotropic effects. Beta blockers with vasodilating properties may have the advantage of overcoming this, however. Carvedilol, a beta-blocking agent with vasodilating properties, was evaluated in 17 patients with chronic CHF secondary to ischemic heart disease with a resting left ventricular ejection fraction less than or equal to 45%, who were being maintained on diuretics. Exercise testing, radionuclide ventriculography, and right-sided cardiac catheterization were performed and intraarterial blood pressure measured before and after 8 weeks of carvedilol therapy in a dosage of 12.5 to 50.0 mg twice a day. Twelve patients completed the study and 5 withdrew. Symptomatic and hemodynamic improvement was demonstrated in 11 of the 12 patients. Heart rate and intraarterial blood pressure were both reduced by chronic therapy. Mean +/- standard deviation exercise time improved from 4.3 +/- 1.6 to 7.1 +/- 2.7 minutes (p less than 0.0001), as did resting left ventricular ejection fraction, from 27 +/- 9 to 31 +/- 11% (p less than 0.02). Pulmonary arterial wedge pressure fell from 19 +/- 7 mm Hg to 12 +/- 5 mm Hg (p less than 0.001) and total systemic vascular resistance from 1,752 +/- 403 to 1,497 +/- 310 dynes/s/cm-5/m2 (p less than 0.02). Stroke volume index improved also, from 31 +/- 6 ml to 40 +/- 6 ml (p less than 0.0005). These hemodynamic changes were mediated partly by vasodilation, diminished myocardial oxygen demand and reduction of sympathetic overactivity in the failing heart. These data suggest that carvedilol may have beneficial effects in patients with chronic CHF secondary to coronary artery disease.

Administration, Oral

Comparison of nicorandil and atenolol in stable angina pectoris.

The efficacy of nicorandil was compared with atenolol in 37 patients with chronic stable angina using a randomized, placebo-controlled, parallel study design. After a single-blind placebo phase, patients were randomized to receive nicorandil or atenolol using a double-dummy technique. Patients took nicorandil 10 mg twice daily or atenolol 50 mg once daily for the first 3 weeks, and if no adverse effects were encountered they took nicorandil 20 mg twice daily or atenolol 100 mg once daily, for the final 3-week phase. Treadmill exercise tests were performed at the end of each treatment phase immediately before and 2 hours after the morning dose of medication. Groups were demographically similar. Placebo exercise times were 7.06 (0.60) minutes (mean +/- standard error of the mean) in the nicorandil group and 6.81 (0.47) minutes in the atenolol group. After 6 weeks, improvements in exercise time were before dosing: +1.47 (0.40) minutes with nicorandil (p less than 0.005) and +1.33 (0.29) minutes with atenolol (p less than 0.001). Improvements after therapy was administered were +2.45 (0.41) minutes with nicorandil (p less than 0.001) and +2.37 (0.43) minutes with atenolol (p less than 0.0001). Whereas, the predose peak exercise double product (heart rate X systolic blood pressure mm Hg/100) was reduced with atenolol (-43.6 units; p less than 0.001), an increase (+7.56 units; difference not significant) was noted with nicorandil. One patient taking atenolol and 5 taking nicorandil developed persistent headaches. One subject with severe 3-vessel coronary artery disease had fatal myocardial infarction within 3 days of starting nicorandil, 10 mg twice daily.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris

Immunoscintigraphy for detecting acute myocardial infarction without electrocardiographic changes.

OBJECTIVE: To establish whether immunoscintigraphy with antibody to myosin may detect acute myocardial infarction without electrocardiographic changes. DESIGN: Prospective study of patients with suspected acute myocardial infarction or unstable angina with cardiac imaging with 111indium myosin antibody, estimation of cardiac enzyme concentrations, electrocardiography, 201thallium imaging, and radionuclide ventriculography. SETTING: Coronary care unit in a district general hospital. PATIENTS: 119 Consecutive patients with suspected acute myocardial infarction or unstable angina. Patients with cardiomyopathy, myocarditis, valvular heart disease, myocardial infarction or cardiac surgery in the previous two weeks or with left bundle branch block and women of childbearing age were excluded. RESULTS: Of 75 patients with suspected acute myocardial infarction, seven had no diagnostic electrocardiographic changes despite normal conduction patterns. Immunoscintigraphy with myosin antibody disclosed necrosis in all seven patients, which was localised in regions supplied by diseased coronary arteries in all but one. Six patients had abnormal images on 201thallium imaging, and all seven had abnormal wall motion at the site of antibody uptake. One patient with minimal left main stem and right coronary artery atheroma had uptake of antibody at two discrete sites. CONCLUSIONS: Immunoscintigraphy with antibody to myosin confirms myocardial infarction in the absence of electrocardiographic changes and discloses the site of infarction.

Adult