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Biomedical subjects

D Hunt

Publications and source records attributed to D Hunt.

At least 109 records · Page 6Linked to original sources
PubMed1989

Early and late results of balloon valvuloplasty for severe aortic stenosis.

Balloon aortic valvuloplasty has been used as treatment for selected patients with severe aortic stenosis. We report our experience of 11 procedures, performed on ten patients between October 1987 and June 1988. The peak aortic systolic gradient was reduced by 53% from 77 +/- 22 to 37 +/- 14 mmHg (p less than 0.0001) whilst cardiac output did not change significantly (4.1 +/- 1.7 to 3.8 +/- 1.6 (p less than 0.0001) whilst cardiac output did not change significantly (4.1 +/- 1.7 to 3.8 +/- 1.6 L/min). Aortic valve area was increased by 50%, from 0.4 +/- 0.2 to 0.6 +/- 0.2 cm2 (p less than 0.0001). Initial symptomatic improvement was achieved in eight patients. Echocardiographically demonstrated aortic regurgitation did not increase after valvuloplasty. There were no deaths during the procedure, no embolic events and no femoral artery complications. The mean follow-up for survivors was 9 +/- 3 months. Five patients died and three had symptom recurrence at an average of 13 weeks (six-24 weeks). Only two patients reported a continued improvement in symptoms. Balloon aortic valvuloplasty produced a small increase in aortic valve area and a satisfactory initial clinical response, but there was a high incidence of symptom recurrence. The procedure may have a role in the short-term palliation of severely symptomatic patients who are unable to have aortic valve replacement.

Acute Disease↗
PubMed1989

Social-psychological environments and cognitive achievement.

Differences in social-psychological environments between parochial and public schools, and between mathematics and English courses, were investigated for 317 boys and girls in Grade 10. Multivariate and univariate analyses of variance produced significant main effects and an interaction of school x subject. Differential validities of environmental variables in predicting achievement using multiple regression suggested that perception of the learning environment for course content substantially predicted achievement in that course content. Incremental validity of the learning environment with achievement when IQ was partialled out was also substantial. Implications for instructional effectiveness and school organization are discussed.

Achievement↗
PubMed1989

The effects of anti-hypertensive drugs on sexual function in men and women: a report from the DHSS Hypertension Care Computing Project (DHCCP).

One thousand, two hundred and eighty-five men and 1,080 women being followed in the DHSS Hypertension Care Computing Project answered the questions on sexual activity included in a self-administered questionnaire. In men, both impotence and sexual inactivity were increased in patients receiving hydralazine. No gross excess of these complaints could be determined in patients receiving either beta-adrenoceptor blocking drugs or methyldopa, nor was failure of ejaculation increased with these drugs. The survey could not exclude any deterioration in sexual function occurring uniformly across all treatment groups. However, the rates of complaint were similar in men taking a diuretic alone, a beta-adrenoceptor blocking drug alone and those taking the combination of these two drug groups. In women with hypertension, frequency of sexual intercourse and the achievement of orgasm was not associated with the giving of hydralazine, beta-adrenoceptor blocking drugs or methyldopa.

Adult↗
PubMed1988

Prevalence of ischaemic ECG abnormalities according to the diabetes status in the population of Fiji and their associations with other risk factors.

The prevalence of ECG abnormalities indicating the presence of coronary heart disease was examined in the Melanesian (444 men and 457 women) and Asian Indian (408 men and 435 women) population living in Fiji. The aim of the present analysis was to determine the levels of coronary risk factors in people with diabetes, impaired glucose tolerance (IGT) or normal glucose tolerance. The prevalence of ECG abnormalities suggesting coronary heart disease (Q-waves, ST-depression or T-wave changes) was higher among women than men and among Asian Indians than Melanesians. The prevalence of ECG abnormalities was highest in diabetic subjects, intermediate in people with IGT and lowest in people who had normal glucose tolerance. People with IGT were more likely than others to have high risk factor levels. In people with IGT the increased levels of other coronary risk factors might explain a great deal of the increased prevalence of the ECG abnormalities as compared with the prevalence in those with normal glucose tolerance. Also in diabetic subjects, the levels of other coronary risk factors were increased in those who had ECG abnormalities, but not more than was the case with IGT, so that diabetes itself seemed to remain as the major identified risk factor for ECG abnormalities. The prevalence of diabetes in our study populations, especially in Asian Indians, was very high. This suggests that diabetes is the major risk factor for coronary heart disease in such populations.

Black People↗
PubMed1988

Short- and long-term results of transvenous catheter ablation of the atrioventricular conduction system.

Twenty-two patients with refractory supraventricular arrhythmias were treated by catheter-delivered high-energy shocks to the atrioventricular conduction system. All patients had a minimum follow-up period of six months (mean +/- SD, 15 +/- 9 months), at which time 21 of the 22 patients were free of symptoms and required no antiarrhythmic therapy. Permanent pacemakers were implanted in all patients. These results show that transvenous ablation or modification of atrioventricular conduction is a safe and effective technique to treat a wide range of supraventricular arrhythmias, and obviates the need for open-heart surgery for the interruption of atrioventricular nodal conduction.

Adolescent↗
PubMed1988

Electrocardiographic abnormalities amongst Melanesian and Indian men of Fiji: prevalence and associated factors.

Electrocardiograms were performed on 427 Melanesian and 391 Indian males aged 30-69 years surveyed in 1980. The age-adjusted prevalence of abnormalities in Minnesota coding suggesting coronary arterial disease was: Indians - 17.1%, Melanesians - 9.1%. This difference was significant at P less than 0.001. For the Melanesians body mass index, plasma uric acid, cholesterol and triglyceride and systolic blood pressure showed significant positive associations with electrocardiographic abnormalities in a univariate analysis, but only the plasma uric acid level was independently associated with such abnormalities following adjustment for these other factors in a multivariate analysis (P less than 0.001). For the Indians body mass index, systolic blood pressure, the presence of diabetes, urban residence and physical inactivity were positively associated with electrocardiographic abnormalities in the univariate analysis, but only body mass index (P less than 0.01), systolic blood pressure (P less than 0.01), and the 2-hour glucose level (P less than 0.01) were independently associated with such abnormalities when adjustment was made for the levels of the other factors.

Adult↗
PubMed1988

Treated blood pressure, rather than pretreatment, predicts survival in hypertensive patients. A report from the DHSS Hypertension Care Computing Project (DHCCP).

A group of hypertensive patients (n = 2855) with an untreated diastolic blood pressure greater than or equal to 90 mmHg were followed in the Department of Health and Social Security (DHSS) Hypertension Care Computing Project (DHCCP) for periods of up to 10 years. During this period 191 of these patients died. Survival was assessed in relation to pretreatment blood pressure levels and blood pressure achieved during treatment. The blood pressure during treatment was a useful predictor of mortality, but the pretreatment pressure was not. After adjusting for age, mortality was particularly related to the height of the systolic and diastolic blood pressure during the second and third years of treatment. In men, age-standardized 5-year mortality was greater than 10% in those with a first year treated systolic pressure greater than 150 mmHg or a diastolic pressure greater than 95 mmHg. In women, age standardized 5-year mortality was greater than 5% with the same levels of treated blood pressure. The longest survival occurred with the lowest bands of treated pressure, i.e. systolic pressure less than 140 and diastolic pressure less than 90 mmHg; the 5-year mortality being less than 7% in men and less than 3% in women. Treated systolic and diastolic pressures were useful in predicting death from ischaemic heart disease (IHD).

Blood Pressure↗
PubMed1988

Assessment of aortocoronary bypass graft patency by intra-arterial digital subtraction angiography compared to selective graft angiography.

The value of digital subtraction angiography (DSA), in assessing aortocoronary bypass graft patency, was evaluated by studying 22 consecutive patients with 54 aortocoronary saphenous vein bypass grafts, who had postoperative angina pectoris. Each patient underwent selective graft angiography and non-gated DSA. The DSA consisted of a run of 15 to 20 frames, taken at 2.3 frames per second during injection of diluted contrast in the ascending aorta, performed after a test exposure was made. Thirty-two of the 54 grafts (59%) were patent. Thirty of the 32 grafts were seen to be patent by both selective graft angiography and DSA. In addition, a further two grafts were found to be patent on DSA, but were not able to be selectively catheterised and were not seen on the conventional aortogram. Selective graft angiography revealed four tight proximal graft stenoses, of which one only was seen on DSA; and poor distal run-off in five grafts, two of which showed up as late filling grafts on DSA. In summary, the accuracy of intra-arterial DSA in assessment of bypass graft patency was excellent. All grafts seen to be patent on selective graft angiography were also seen by DSA alone and in addition two grafts which could not be selectively catheterised were found to be patent. However, in patients with postoperative chest pain, selective graft angiography is probably required as non-gated intra-arterial DSA does not provide sufficient information to assess graft stenoses, distal flow and the native coronary vessels.

Adult↗
PubMed1988

The role of permanent pacing after anterior myocardial infarction complicated by transient complete atrioventricular block.

A randomised study was performed to assess the influence of prophylactic permanent pacing on the incidence of late sudden death in patients surviving transient complete atrioventricular block with acute anterior myocardial infarction. Fourteen patients were studied, of whom ten died within two years, confirming the high overall late mortality in this group. The deaths included eight of the nine paced patients, of whom seven died suddenly. We conclude that prophylactic permanent pacing is not warranted in patients surviving transient complete atrioventricular block with acute anterior myocardial infarction.

Adult↗
PubMed1988

Long-term clinical and angiographic results following percutaneous transluminal coronary angioplasty.

The long-term results of percutaneous transluminal coronary angioplasty were evaluated in our first 42 patients, who had initial successful angioplasty and no restenosis on angiogram performed four months after angioplasty. Evaluation included repeat follow-up angiogram performed approximately two years after angioplasty in 22 of the 42 patients. All 42 patients had single vessel disease with severe angina pectoris refractory to medical treatment before angioplasty; at a mean follow-up of 28 months after angioplasty, 37 (88%) were asymptomatic. No patient died or underwent coronary artery bypass graft surgery during the follow-up period, although three patients (7%) suffered a myocardial infarction due to occlusion of a nondilated artery. In the 22 cases studied at a mean of 28 months after angioplasty, angiogram showed that successful coronary artery dilatation remained in all cases, with no deterioration of a dilated lesion between the four and 28 month angiograms. Progression of atherosclerosis, however, did occur in five of the 22 patients (23%), with development of either stenosis or occlusion of a non-dilated vessel. This study suggests that the development of restonsis between four and 28 months after percutaneous transluminal coronary angioplasty is unlikely. The results suggest an excellent long-term prognosis after angioplasty, in patients who have no evidence of restenosis at four months after an initially successful dilatation.

Adult↗
PubMed1988

The porous titanium steroid eluting electrode: a double blind study assessing the stimulation threshold effects of steroid.

A transvenous pacing lead with a porous electrode which slowly elutes the steroid, dexamethasone sodium phosphate, has been developed. Previous investigations show low and constant stimulation thresholds persisting over at least the first two years post-implantation. As it is not known whether this low threshold results from the steroid or electrode configuration, a double blind study was designed to compare the same electrode configuration with and without steroid over a 2-year follow-up period. There were ten patients in each group with similar age, sex, indications for pacing and implantation data. Regular measurements of postoperative pulse duration thresholds were performed using a customized VVIM pulse generator programmed to 1.5 V output. For the first two days post-implantation, there were no statistical differences in the pulse duration thresholds between the two pacing leads. From 2 weeks to 2 years the pulse duration thresholds for the steroid leads remained almost constant, whereas the leads without steroid showed a typical rise. The difference in pulse duration thresholds between the two groups of leads from two weeks onwards confirmed that it was the steroid rather than the electrode configuration which prevented the rise in chronic stimulation threshold.

Aged↗
PubMed1988

Rate responsive pacing using a minute ventilation sensor.

Minute ventilation, the product of respiratory rate and tidal volume, correlates directly with oxygen consumption, cardiac output, and heart rate. An implantable pacemaker has been developed which allows variation in pacing rate in response to measured changes in minute ventilation. This single chamber system measures transthoracic impedance between the tip electrode of a standard bipolar lead and the pulse generator case. Low amplitude current pulses (1 mA for 15 microseconds) are generated each 50 msec between the the ring electrode and the case. In the adaptive mode, the pulse generator calculates a rate response factor or slope after maximal exercise. This slope, which describes the relationship between pacing rate and minute ventilation together with the pacing rate limits are the only programmable rate responsive features. Minute ventilation rate responsive systems have been implanted in 12 patients (8 females, 4 males), of mean age 63 years. Indications were His bundle ablation (6), acquired complete heart block (4), and sick sinus syndrome (2). At post-implant exercise testing, pacing rate rose within the first minute. Peak rate and time to upper rate were dependent on workload. After exercise, pacing rate remained at peak for up to 2 minutes before a gradual fall to resting rate. Comparative studies of the minute ventilation and the activity sensor pacing systems in the same patients confirmed that the minute ventilation system more closely parallels normal sinus response to activity. The minute ventilation rate responsive pacing system is simple to programme, no special lead is required and the system is highly physiologic.

Aged↗
PubMed1988

Beta adrenoceptor blockade is associated with increased survival in male but not female hypertensive patients: a report from the DHSS Hypertension Care Computing Project (DHCCP).

The DHCCP is a multicentre observational study of patients being treated for hypertension in the United Kingdom. The influence of the type of anti-hypertensive therapy on survival was examined in 2,697 patients followed from 1971 with 206 deaths up to November 1981. Patients were classified by three types of treatment after one year in the project: betablockers (1,387), methyldopa (452) and others (667), (70% on diuretics only). The data were analysed both for all patients and for a subset excluding patients with previous ischaemic heart disease by all cause and IHD age-adjusted rates and life table analysis. Men on beta blockers had lower rates for total mortality, when compared with men on methyldopa (64% of the methyldopa rate, P less than 0.05) and when compared with men on other treatments (76% of the other treatment rate, P less than 0.1). The results for IHD mortality were similar. This improved survival of men in the beta blocker group was also found in the subset with no prior history of IHD. The benefit of beta blockers was not apparent in women: the lowest rates were observed for women on methyldopa, but the confidence limits for the ratios of relative rates were wide. Adjustment for blood pressure and cigarette smoking using the Cox proportional hazards model did not substantially modify the ratios of the mortality rates for the treatment groups. A sub-group analysis showed the reduction in all cause and IHD mortality associated with beta blockers was mainly due to the effect in non-smoking men.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1988

The relationship between a low treated blood pressure and IHD mortality: a report from the DHSS Hypertension Care Computing Project (DHCCP).

The suggestion that treating blood pressure to below a certain level may increase IHD mortality is controversial. We investigated the influence of treated blood pressure on mortality in the DHSS Hypertension Care Computer Project. Mortality was examined by quintiles of treated diastolic blood pressure (DBP) in 2,145 patients treated for a minimum period of one year and subsequently followed for an average of four years. One hundred and seventy five patients died; 71 from IHD. In men and women all cause mortality increased with level of treated DBP. In men IHD mortality showed a U-shaped distribution with an age-adjusted rate of 15.2 per 1,000 person years in the lowest fifth (DBP less than 86 mmHg) comparable to that of 15.6 per 1,000 in the upper (DBP greater than or equal to 103 mmHg). A similar pattern could not be established in women due to very few IHD deaths. IHD mortality was further examined separately for men by prior history of IHD. An increase in IHD deaths in the lowest fifth of treated blood pressure was found for men both with and without a history of IHD. No similar pattern of IHD mortality was obtained for untreated DBP or treated systolic pressure. However, we cannot exclude the possibility that the risk of low treated DBP is secondary to ischaemic heart disease.

Age Factors↗
PubMed1987

Benign congenital intracardiac thyroid and polycystic tumor causing right ventricular outflow tract obstruction and conduction disturbance.

A patient with a rare intracardiac tumor arising from the right side of the interventricular septum who developed conduction disturbances and symptoms of right ventricular outflow tract obstruction is reported. The patient was successfully treated with insertion of a permanent pacemaker and surgical removal of the tumor after two-dimensional echocardiography diagnosed the intracardiac mass. Pathologic examination confirmed the benign nature of the tumor and showed the unusual features of both ectopic thyroid and benign congenital polycystic tumor.

Choristoma↗