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Biomedical subjects

N G Dewhurst

Publications and source records attributed to N G Dewhurst.

At least 19 recordsLinked to original sources
PubMed2003

Continuous PC6 wristband acupressure for relief of nausea and vomiting associated with acute myocardial infarction: a partially randomised, placebo-controlled trial.

OBJECTIVES: To assess the effectiveness of continuous PC6 acupressure as an adjunct to antiemetic drug therapy in the prevention and control of nausea and vomiting in the first 24h after myocardial infarction (MI). DESIGN: Partially randomised, partially blinded placebo-controlled, exploratory clinical study. SETTING: Coronary Care Unit, Torbay Hospital, Torquay, Devon. PARTICIPANTS: A total of 301 consecutive patients (205 males, 96 females) admitted following acute MI. INTERVENTION: The first 125 patients recruited received no additional intervention. Subsequent patients were randomised to receive either continuous PC6 acupressure or placebo acupressure. OUTCOME MEASURES: (1) Incidence of post-MI nausea and/or vomiting, (2) severity of symptoms, (3) use of antiemetic drugs, over 24h. RESULTS: There were no significant differences between the groups for the whole 24-h treatment period. However, the PC6 acupressure group experienced significantly lower incidence of nausea and/or vomiting during the last 20h (18%), compared with the placebo (32%) or control (43%) groups (P<0.05). The severity of symptoms and the need for antiemetic drugs were also reduced in the acupressure group, but these differences were not statistically significant. CONCLUSIONS: Continuous 24-h PC6 acupressure therapy as an adjunct to standard antiemetic medication for post-MI nausea and vomiting is feasible and is well accepted and tolerated by patients. In view of its benefits, further studies are worthwhile using earlier onset of treatment.

Acupressure↗
PubMed2002

An unusual cause of chest pain.

Pericardial cysts are rare mediastinal cysts, which are commonly asymptomatic. We report the case of a middle-aged lady, with a previous short history of chest pain, who was found to have a focal pericardial density, felt to have been a consequence of haemorrhage into such a cyst.

Chest Pain↗
PubMed2000

Results of a survey of cardiovascular risk factor prevalence amongst health care workers. The Executive Committee of SHARP--(Scottish Heart and Arterial Risk Prevention).

Summary analyses of screening data were used to ascertain the cardiovascular risk profile in a sample of health care workers in Scotland. A sample of NHS staff (298 women and 78 men) were screened during visits to Perth Royal Infirmary (PRI) in 1996 and 1997. Comparisons were made within subsets and with previous screening studies. Health care workers have been a neglected component of the workforce for receiving education about risk factors. The high prevalence of smokers found in this sample should be a cause for concern.

Adult↗
PubMed1996

The concept of cardioreparation: Part 2. Medical implications of cardioreparation.

PURPOSE: Left ventricular hypertrophy (LVH) caused by systemic hypertension, myocardial infarction and congestive heart failure is associated with pathological changes in the structure of the heart, collectively described as remodelling (see part 1 of this review). The reversal of remodelling, termed cardioreparation, might restore cardiac structure and function towards normal, thereby improving the prognosis of these conditions. We aimed to explore the medical implications of this concept. DATA EXTRACTION: Clinical trials of angiotensin converting enzyme (ACE) inhibitors and other drugs in patients with hypertension, myocardial infarction and congestive heart failure were reviewed. The results showed that ACE inhibitors induce regression of LVH in hypertensive patients, reduce mortality in acute myocardial infarction, and reduce morbidity and mortality in patients with congestive heart failure or left ventricular dysfunction subsequent to myocardial infarction. These observations are consistent with cardioreparation by ACE inhibitors. CONCLUSIONS: ACE inhibitors reduce morbidity and mortality in patients with myocardial infarction or congestive heart failure. Theoretical considerations and some clinical observations suggest that these benefits might result from cardioreparation.

Antihypertensive Agents↗
PubMed1987

Heart failure.

Explore the source record for details and available documents.

Adult↗
PubMed1987

Severe pulmonary hypertension and multiple left coronary arterial fistulas in association with congenital hepatic fibrosis.

Multiple fistulous communications between the left anterior descending coronary artery and the left ventricle were found in a 55 year old woman with congenital hepatic fibrosis presenting with breathlessness. At cardiac catheterisation severe pulmonary hypertension was also found. In view of the persistent hypoprothrombinaemia, severe thrombocytopenia, and the multiple fistulas the risk of operation was thought to be unacceptable and she continues on medical treatment.

Coronary Vessel Anomalies↗
PubMed1986

Diagnosis and prognosis of right ventricular infarction.

The values of several non-invasive methods for the diagnosis of right ventricular necrosis in inferior myocardial infarction were compared in 51 consecutive patients who underwent serial radionuclide ventriculography, pyrophosphate scintigraphy, and cross sectional echocardiography. In addition a unipolar electrocardiographic lead V4R was recorded on admission, daily, and during episodes of further pain. Profound right ventricular dysfunction was evident in 50% of patients studied by radionuclide methods after inferior myocardial infarction but recognition on clinical groups alone was poor. Functionally important right ventricular infarction was best detected and followed serially by radionuclide ventriculography. Echocardiographic methods for evaluating right ventricular ejection fraction correlated poorly with radionuclide methods. Increased uptake of radioactivity by the right ventricle on pyrophosphate scintigraphy usually indicated poor right ventricular function, but a scan that was negative in the right ventricular territory did not exclude dysfunction. ST segment elevation in V4R was not specific for right ventricular infarction and its routine use may lead to overdiagnosis of this condition. Serial measurements suggest that profound right ventricular dysfunction persists after acute inferior infarction and is associated with considerable morbidity and mortality. Of 25 patients with severe right ventricular dysfunction, six died in the late hospital period. In the remaining 19 patients mean right ventricular ejection fraction over a two month period did not improve; six patients had persistent right ventricular dyskinesia and features of chronic right ventricular failure developed in three survivors.

Adult↗
PubMed1985

Clinical significance of "reciprocal" S-T segment depression in acute myocardial infarction. Relative contributions of infarct size and ischemia at a distance.

The early electrocardiographic results in 100 patients surviving their first myocardial infarction who thereafter underwent serial radionuclide ventriculography were reviewed. Site of infarction was anterior in 46 and inferior in 54, with lateral extension in two patients. Those with "reciprocal" S-T segment depression of more than 1 mm in the acute phase (n = 53) sustained larger infarcts on the basis of enzyme criteria (mean peak serum creatine kinase, +/- SD, 2,203 +/- 1,271 versus 1,544 +/- 1,197 IU/liter, p less than 0.02), with a higher incidence of ventricular akinesis and dyskinesis. Reciprocal change was more common during inferior infarction (n = 33) than anterior infarction (n = 20). Despite equivalent peak enzyme levels following anterior and inferior infarction with reciprocal S-T depression (mean peak creatine kinase 2,330 versus 2,128, NS), there was marked sparing of left ventricular function in the latter group (mean left ventricular ejection fraction 0.31 +/- 0.14 versus 0.42 +/- 0.09, p less than 0.01). Of 17 patients who died within two years of infarction, 14 had reciprocal changes. Patients who died after anterior infarction with reciprocal changes (n = 5) had poor left ventricular function compared with those who died after inferior infarction (n = 9; left ventricular ejection fraction, +/- SD, 0.21 +/- 0.05 versus 0.38 +/- 0.11, p less than 0.01). One third of those recovering from inferior infarction with reciprocal changes subsequently had positive results on exercise testing, and of the nine patients who died, five had good left ventricular function (left ventricular ejection fraction 0.44 to 0.50). Infarct size and ventricular wall motion abnormality proved to be of major importance in the production of inferior reciprocal S-T change during anterior infarction, and subsequent mortality was related to poor left ventricular function. The proximity of the precordial leads to left ventricular myocardium may increase the detection of concomitant anterior ischemia during inferior infarction, and those who exhibit reciprocal change are presumably at risk from left main stem or anterior descending lesions but with reasonably good ventricular function represent a more attractive population for invasive investigation.

Creatine Kinase↗
PubMed1984

Ventricular performance and prognosis after primary ventricular fibrillation complicating acute myocardial infarction.

To examine the relationship between early arrhythmias, infarct size and prognosis, we compared 22 consecutive patients surviving acute myocardial infarction (AMI) and primary ventricular fibrillation (VF) with a control population after AMI uncomplicated by primary VF. Left ventricular ejection fraction (EF) was measured by radionuclide ventriculography before discharge from hospital. Mean EF was significantly reduced below normal following AMI with or without primary VF (normal 0.57 +/- 0.05, mean +/- SD; P less than 0.01). Mean EF was lower among patients who survived primary VF than among those with infarction uncomplicated by primary arrhythmia (0.33 +/- 0.12 v. 0.46 +/- 0.07; P less than 0.01). There were striking differences in EF between those patients with anterior and those with inferior infarction. Mean EF for those surviving primary VF after transmural anterior infarction (0.23 +/- 0.06) was lower than those who had primary VF after transmural inferior infarction (0.43 +/- 0.06; P less than 0.01). Normal left ventricular function was seen in four individuals who developed no further complications. Recurrent primary ventricular arrhythmia was seen only in those individuals subsequently shown to have reduced EF. Low EF (less than 0.35) was seen in 12 patients with primary VF in the context of anterior infarction, five developed breakthrough ventricular arrhythmias despite therapy and in a limited follow-up period, three have died.

Adult↗
PubMed1981

An index of valvular regurgitation from a radionuclide bolus.

Mitral and aortic regurgitation was assessed from analysis of activity-time curves from right and left ventricles following the intravenous bolus injection of 99Tcm-labelled human serum albumin. The differences in the initial arrival times and the mean transit times for the ventricles were combined to provide an index of regurgitation. The mean index for 18 patients with good ventricular function and no regurgitation was -0.07 +/- 0.55 (SD) seconds. This was not significantly different from the mean value of 0.39 +/- 1.22 s obtained for 9 patients with left ventricular failure but no regurgitation. The indices for 16 patients with mitral or aortic regurgitation agreed well with the severity as assessed by contrast angiography. The mean indices for the mild, moderate and severe regurgitation groups were 2.62 +/- 1.13 s, 5.30 +/- 3.05 s and 10.15 +/- 3.62 s respectively.

Aortic Valve Insufficiency↗
PubMed1981

The effects of intravenous prenalterol on ventricular performance, as assessed by radionuclide ventriculography, in patients with ischaemic heart disease.

1 We have observed the effects of intravenous prenalterol (1 mg and 2 mg) on ventricular performance, assessed by radionuclide ventriculography, in nine patients with ischaemic heart disease with varying degrees of impairment of ventricular performance. In seven of these patients the effects of prenalterol were compared with those of isoprenaline infused at 1 microgram/min. 2 Prenalterol caused no significant increase in heart rate, but systolic blood pressure increased by 26% (P less than 0.002). In contrast, isoprenaline caused heart rate to increase by 22% (P less than 0.02) and diastolic blood pressure to fall by 9% (P less than 0.01). 3 Left ventricular ejection fraction (LVEF) increased with both drugs, but the increase was greater with isoprenaline, as was the fall in the ratio mean ejection time: left ventricular ejection time, which is an index of improved ventricular performance. 4 Because of the increased heart rate and stroke volume produced by isoprenaline, cardiac output increased 45% above control values (P less than 0.001), but the increase in cardiac output after prenalterol did not reach statistical significance. 5 In three patients with very poor ventricular function (LVEF less than 0.30) prenalterol had little effect on ejection fraction, and caused increased regional ventricular dyskinesia. 6 The increase in systolic blood pressure, and therefore cardiac afterload brought about by prenalterol may limit ventricular response. The response might be enhanced by the addition of vasodilator therapy.

Blood Pressure↗
PubMed1981

Radionuclide determined pulmonary blood volume in ischaemic heart disease.

Most measurements of pulmonary blood volume have been based on the Stewart-Hamilton dye dilution principle and have required direct catheterisation of the cardiac chambers. Alternatively a precordial counter may be used to detect the composite right and left heart curves after an intravenous injection of radionuclide. We investigated the use of a gamma camera/computer system to determine the radionuclide dilution curves from individual cardiac chambers. Pulmonary transit time and pulmonary blood volume were measured in nine normal subjects, eight patients with angina pectoris but without heart failure, and 13 patients with ischaemic heart disease and left ventricular failure. Patients with heart failure had significantly greater (p less than 0.001) pulmonary blood volumes and pulmonary transit times than normal subjects or patients without heart failure. Reproducibility measurements of pulmonary blood volume, determined in 12 subjects, gave a coefficient of variation of 2.6%. The effect of posture on pulmonary blood volume was determined in six subjects lying supine and tilted at a 45 degree angle. A reduction in pulmonary blood volume in the tilted position was observed in each subject (p less than 0.005). This simple non-invasive measurement should allow more detailed assessment of physiological or pharmacological changes of the pulmonary vascular bed.

Blood Volume↗
PubMed1980

The influence of ectopic heart beats in gated ventricular blood-pool studies.

Direct data collection from ventricular blood-pool studies were stored in frame mode in a computer and by means of a modified tape recorder, the blood-pool image and ECG were recorded on tape. At the end of the study the tape data were replayed into the computer. The ECG signal was passed through a trigger circuit that detected the R wave which was sampled by the computer once every msec. Contractions outside of the desired range could be rejected along with the subsequent contraction. Of seven patients whose calculated ejection fractions were changed by more than 0.03, all had frequent (one in 20) ectopic contractions. The distorted ventricular volume curves were effectively restructured by the constraining procedure, changing the end-systolic volume and EF. Computer modeling showed a linear relationship between the percent of ectopic contractions and the underestimate of ejection fraction. One ectopic beat in ten led to a 5% underestimate of EF.

Cardiac Complexes, Premature↗
PubMed1980

Prognostic value of radionuclide ventriculography after myocardial infarction.

We have studied 50 consecutive patients who had sustained their first myocardial infarction. Using the noninvasive technique of radionuclide ventriculography, ventricular performance, as assessed by left ventricular ejection fraction (EF), was measured at rest just before discharge from hospital when patients were well and free from cardiac failure and then at one and four months after infarction, at rest and during submaximal supine exercise. Left ventricular ejection fraction was below normal in 42 patients (normal range 0.43-0.71). Mean EF for those patients recovering from inferior infarction was 0.43 +/- 0.09 (mean +/- 1 S.D.), whereas for those who had sustained anterior infarction mean EF was significantly lower, 0.33 +/- 0.13 (p less than 0.01). EF was significantly reduced (p less than 0.01) in those patients whose early progress was complicated either by serious arrhythmia or left ventricular failure. There was only poor correlation between EF and radiographically determined heart size but global left ventricular performance correlated well with the presence of abnormalities of regional wall movement. Over the first four months low EF failed to improve in seven patients with areas of dyskinesis (EF less tha 0.30) and despite diuretic therapy five suffered further episodes of cardiac failure. Excluding those with dyskinesis there were 18 patients who were unable to increase EF on exercise on month after infarction. Of these four already had symptoms of angina but a further 10 patients developed angina in the subsequent three months. Poor left ventricular performance is common after anterior myocardial infarction, complicated in the acute phase by serious arrhythmia or left ventricular failure. Patients with persistently low EF had an increased risk of further episodes of cardiac failure, whereas a fall in EF on exercise was associated with subsequent angina.

Adult↗