Search PubMed⌕ Search

Biomedical subjects

M Hartford

Publications and source records attributed to M Hartford.

At least 73 records · Page 4Linked to original sources
PubMed1992

Withdrawal of antihypertensive drug treatment: time-course for redevelopment of hypertension and effects upon left ventricular mass.

OBJECTIVES: To examine: (1) in how many treated hypertensive patients it was possible to discontinue drug treatment; (2) the time-course for redevelopment of hypertension after discontinuation of therapy; and (3) whether drug withdrawal was associated with an increase in left ventricular mass (LVM). DESIGN: Fifty-four men with primary hypertension treated for a mean period of 6 years (primarily beta 1-selective beta-blockade) were evaluated for withdrawal of treatment. Exclusion criteria were signs of organ damage, severe hypertension, other serious disease and unwillingness. Treatment was reinstituted if blood pressure increased above a safety level or if symptoms occurred. Echocardiographic estimations of LVM were obtained before withdrawal and 1, 4 and 8 weeks after withdrawal or before return to treatment. SETTING: Outpatient clinic in a city hospital. PATIENTS: A random sample of 56-year-old hypertensive men. INTERVENTION: Gradual discontinuation of treatment with close follow-up of blood pressure. MAIN OUTCOME MEASURES: Number of patients who could withdraw from treatment and who had to return to pharmacological therapy; time-courses for development of hypertension; absolute changes in LVM. RESULTS: Thirty-two patients withdrew from treatment for 1-1000 days. Therapy was reinstituted in all owing to hypertension or symptoms. Serial echocardiograms were obtained in 22 patients. During the drug-free period, relative wall thickness increased, but LVM did not. Patients with rapid redevelopment of hypertension had larger prewithdrawal LVM than patients whose blood pressure increased more slowly. CONCLUSION: It was possible to withdraw treatment and obtain readable echocardiograms in a minority of the patients. After drug-withdrawal, relative wall thickness increased, but not LVM. We suggest that previously treated patients should be avoided in studies examining reversal of left ventricular hypertrophy.

Antihypertensive Agents↗
PubMed1991

Effect of a media campaign to reduce delay times for acute myocardial infarction on the burden of chest pain patients in the emergency department.

We evaluated the effect of a media campaign aimed at reducing delay times in suspected acute myocardial infarction (AMI) on the volume of chest pain patients seen in the emergency department. During the 1st week of the campaign, the mean number of chest pain patients increased from 10.5 per day prior to the start to 25.4. However, the number declined rapidly in subsequent months. The greatest increase was observed in patients with chest pain in whom AMI was not suspected on examination. During the campaign, 4,805 patients with chest pain appeared in the emergency department as compared with 4,407 patients during the same time period prior to its start, an increase of 9%. The number of patients with confirmed AMI increased from 595 to 629 (6%).

Chest Pain↗
PubMed1991

Effect of early intravenous rt-PA on infarct size estimated from serum enzyme activity: results from the TEAHAT Study.

In 319 patients who participated in a double-blind trial to evaluate the effect of early rt-PA administration compared to placebo in suspected acute myocardial infarction, infarct size was assessed from analyses of serum activity of lactate dehydrogenase isoenzyme 1 (LD 1). Treatment was always started less than 3 h after the onset of symptoms, with one-third of the patients' treatment being initiated outside the hospital. The maximum activity of LD 1 was reduced by 32%, from 13.3 mu kat l-1 in placebo to 9.0 mu kat l-1 in rt-PA treated patients (P = 0.001). A reduction in LD-1 activity after rt-PA treatment was restricted to patients with ST-elevation in the initial electrocardiogram, and was more pronounced in patients with previous ischaemic heart disease, above median age, and in those with a shorter delay in initiation of treatment. We conclude that very early intravenous treatment with rt-PA limits indirect signs of infarct size. The effect appears to be restricted to patients with ST-segment elevation in their initial electrocardiogram.

Ambulatory Care↗
PubMed1991

Early thrombolytic therapy in suspected acute myocardial infarction--role of the electrocardiogram: results from the TEAHAT Study.

In a placebo-controlled trial in which rt-PA was administered to patients within 2 h and 45 min after the onset of symptoms indicative of acute myocardial infarction (AMI), 352 patients were randomized. Standard 12-lead electrocardiograms (ECGs) were recorded at inclusion and repeatedly during admission and at follow-up after 1 month and 1 year. In patients who presented with ST-segment elevation, the infarction rate was high (88%), whereas in patients without ST-elevation the infarction rate was low (21%), and infarct size, as assessed by serum enzyme activities, was small in this group. There were only minor differences between rt-PA- and placebo-treated patients with regard to ST-segment changes and Q-wave development, whereas the R-wave amplitude was higher after 1 month in patients who were given rt-PA. The infarction rate was not altered by rt-PA, but there was a shift towards a reduction in Q-wave infarction in patients who were treated with rt-PA. When a score system, as suggested by Palmeri et al., intended to reflect the ultimate infarct size, was applied, a significantly lower score was found in infarction patients who were treated with rt-PA as compared to placebo (3.95 +/- 0.35 vs. 2.95 +/- 0.29, P = 0.03), indicating limitation of infarct size. In summary, early treatment with rt-PA resulted in less frequent Q-wave infarction and a reduction in the electrocardiographically estimated infarct size.

Aged↗
PubMed1991

Effects on chest pain of early thrombolytic treatment in suspected acute myocardial infarction: results from the TEAHAT Study.

In a randomized, double-blind study, in which recombinant tissue plasminogen activator (rt-PA) administered at an early stage was compared with placebo in patients with suspected acute myocardial infarction (AMI), the effects on pain were studied in 312 patients. Inclusion criteria were as follows: (a) chest pain of duration less than 2 h and 45 min; and (b) age less than 75 years. Chest pain was estimated subjectively by the patients, using a 10-point numerical rating scale, at hourly intervals for the first 24 h, and by the requirement for narcotic analgesics. Compared with placebo, rt-PA treatment resulted in a 43% reduction in mean total pain score (P less than 0.0001), a 26% reduction in pain duration (P less than 0.01), and a 33% reduction in morphine requirement (P = 0.01). Fifty-seven per cent of all patients developed a confirmed AMI. In these subjects rt-PA reduced the pain score by 46% (P less than 0.001). Among patients without confirmed AMI, a 37% reduction in pain score was observed (P = 0.05). The effect on pain was most marked in patients with ST-elevation on the initial ECG. We conclude that early treatment with rt-PA in suspected AMI reduces chest pain considerably. The effect is most marked in patients with ST-elevation on the initial ECG.

Aged↗
PubMed1991

Prehospital thrombolysis in suspected acute myocardial infarction: results from the TEAHAT Study.

In a randomized, double-blind study, rt-PA vs. placebo treatment in early suspected acute myocardial infarction (AMI) was evaluated in patients both in hospital and prehospitally. The inclusion criteria were as follows: (a) age less than 75 years; and (b) chest pain indicative of AMI, of no longer than 2.75 h duration before first examination. In the prehospital setting a mobile coronary-care unit, accompanied by a cardiologist, was sent out by the ambulance services to 350 patients, of whom 205 (59%) were classified as non-eligible when examined by the cardiologist. Of the 145 patients who fulfilled the inclusion criteria, 44 were excluded due to contraindications to thrombolytic treatment. Thus 101 patients were randomized to blinded treatment outside hospital. The median time interval between onset of pain and treatment was 75 min, 45 min less than for those subjects who were randomized in hospital. The prevalence of confirmed AMI was 42% in the prehospital group, compared to 66% in the hospital group. Bleeding and cardiac complications for prehospital treatment were few, and similar to those for hospital treatment. In conclusion, prehospital thrombolysis was feasible, and delay times prior to treatment were significantly reduced. However, the specificity and diagnostic accuracy were lower than those achieved with in-hospital therapy.

Aged↗
PubMed1991

Mortality and morbidity 1 year after early thrombolysis in suspected AMI: results from the TEAHAT Study.

We randomized 352 patients with suspected acute myocardial infarction (AMI) to treatment with rt-PA (n = 177) or placebo (n = 175). Patients were eligible if evaluated within 2 h and 45 min from onset of chest pain, and if aged less than 75 years. There were no ECG criteria for inclusion. A mobile coronary-care unit with a cardiologist present was used to initiate treatment at home in 29% of cases. During 1 year of follow-up the mortality in patients treated with rt-PA was 10.2%, as compared with 14.3% in patients the initial ECG, the mortality during the first year was 8% in the rt-PA group vs. 18% in the placebo group (P less than 0.05). Among patients without ST-elevation the mortality was 9% for the rt-PA group vs. 12% for the placebo group (NS). Requirement for rehospitalization, symptoms of angina pectoris and congestive heart failure, time of return to work and requirement for various medications did not differ significantly between the two groups, regardless of the initial ECG pattern.

Aged↗
PubMed1991

Reaction to a media campaign focusing on delay in acute myocardial infarction.

A media campaign conducted to reduce delay time and to increase the use of ambulance transport in acute myocardial infarction was performed in an urban area with about half a million inhabitants during 1 year. The main message was that chest pain lasting more than 15 minutes might indicate acute myocardial infarction; dial 90,000 immediately for ambulance transport to the hospital. The target population was the general public. After 6 and 12 months 400 and 610 randomly chosen persons, respectively, were contacted by telephone to evaluate the reaction of the general public to the campaign. Of these, 60% and 71%, respectively, had heard of the campaign, and all parts of the message were spontaneously remembered by 15% and 19%, respectively. The reaction to the campaign was generally positive. Among all patients admitted to the coronary care unit of one of the two city hospitals, 65% were aware of the campaign and 31% of them were of the opinion that they came to the hospital faster because of the campaign. In conclusion, a media campaign aimed at reducing patient delay time in acute myocardial infarction was shown to reach a majority of people in the community and patients with ischemic heart disease. The reaction was positive and about one fifth of interviewed people spontaneously remembered the total message.

Adult↗
PubMed1990

Components of delay time in suspected acute myocardial infarction with particular emphasis on patient delay.

Two hundred and thirty-four patients admitted to a coronary care unit (CCU) were interviewed a few days after arrival in hospital to determine reasons for patient delay and the various components of total delay time from onset of symptoms to arrival in CCU. Of the three major components of delay, decision time (time from onset of symptoms to decision to go to hospital), and hospital procedure time (time from arrival in hospital to arrival in the CCU), were of the same magnitude, 1 h 15 min and 1 h 30 min (median), whereas the median time for preparation and transportation to hospital was somewhat shorter, being 45 min. Decision time appeared to be similar in patients with confirmed and non-confirmed acute myocardial infarction (AMI) and was not associated with intensity of pain or infarct size. Half of the patients hesitated to go to hospital, which resulted in a prolonged decision delay (3 h). It is concluded that patient indecision to seek medical help is the most important reason for delay in hospital arrival in patients with suspected AMI.

Aged↗
PubMed1989

Delay time in suspected acute myocardial infarction and the importance of its modification.

This paper summarizes the present knowledge of delay time in suspected acute myocardial infarction. More than 50% of deaths in acute myocardial infarction occur outside of the hospital setting. Recent experiences indicate that early and even late mortality can be dramatically reduced by intervention in the early phase. This points up the importance of bringing patients with suspected acute myocardial infarction to the hospital as early in the course of MI as possible. The predominating cause of delay is the time it takes for the patient to decide to go to hospital regardless of a previous history of cardiovascular disease. Patients arriving in hospital in later stages of MI are at a very high risk of mortality. Therefore one of the most important problems to be resolved is how to reduce delay time in suspected acute myocardial infarction. Such efforts have been surprisingly few. Limited experiences indicate that public education can reduce delay time dramatically.

Asia↗
PubMed1989

Radiological heart enlargement in treated hypertensive men: a comparative study of chest X-ray examination and M-mode echocardiography.

Twenty-five hypertensives with no history of myocardial infarction and with a radiologically determined heart enlargement were examined with M-mode echocardiography and compared with a normotensive control group (n = 41). All except two of the hypertensive patients were on a beta-blocker based antihypertensive treatment regime. The relative heart volume on X-ray was significantly larger in the hypertensives, 562 ml m-2 body surface area (BSA), compared to the normotensives, 408 ml m-2 BSA (P less than 0.001). Both left ventricular diameter (LVD) in end-diastole and end-systole and left arterial (LA) diameter were significantly larger in the hypertensives (56 vs. 51 mm, P less than 0.01; 35 vs. 31 mm, P less than 0.01; 46 vs. 42 mm, P less than 0.01, respectively) as was the LV mass (296 vs. 203 g, P less than 0.001). The end-systolic wall stress (ESWS) was significantly greater in the hypertensives. Despite these findings resting left ventricular fractional shortening was the same and showed a similar correlation with ESWS (r = 0.79 and r = 0.77, respectively) in both groups. Hence, left ventricular systolic performance was not impaired in the hypertensives compared to the normotensives. These results show that an enlarged cardiac silhouette on the chest X-ray in hypertensive subjects with beta-blocker based drug therapy must be interpreted with caution and must not, a priori, be judged as a sign of an impaired systolic cardiac function.

Adrenergic beta-Antagonists↗
PubMed1989

Atrial natriuretic peptide (ANP) in relation to blood pressure: a study in middle-aged men with normal and elevated blood pressure.

In order to investigate the potential role of atrial natriuretic peptide (ANP) in mild to moderate essential hypertension, a study was conducted in groups of normotensive and hypertensive middle-aged men born in 1926 and 1927. Venous plasma concentrations of immunoreactive ANP (irANP) were studied in relation to measurements of cardiac structure and function, urinary electrolytes as well as some cardiovascular hormones. Plasma irANP did not differ between normotensive controls (31 +/- 14 pmol l-1) and borderline or untreated hypertensive patients. However, irANP concentrations were slightly but significantly (P less than 0.05) lower in the borderline (26 +/- 8 pmol l-1) compared to the untreated established hypertensives (35 +/- 14 pmol l-1). No relationships were found between irANP and blood pressure, indices of left ventricular structure and function or hormone parameters in subgroups or the whole study group. Our data do not support the view that plasma irANP is increased in uncomplicated essential hypertension, since our groups of borderline or established hypertensive middle-aged men without major cardiac involvement did not differ in irANP concentrations compared to normotensive controls. Thus, during the development or in the early stages of essential hypertension, ANP secretion does not seem to be abnormal.

Antihypertensive Agents↗
PubMed1988

Cardiovascular and renal effects of long-term antihypertensive treatment.

To study whether restoration of a normal circulatory system could be achieved with antihypertensive treatment, 13 hypertensive men with structural cardiovascular changes and 37 normotensive control subjects were investigated by echocardiography, apexcardiography, plethysmography, inulin and p-amino-hippurate clearance, and determination of 24-hour urinary excretion of albumin, first at age 49 years and again seven years later. All men were untreated at the first investigation. Immediately thereafter, therapy with the cardioselective beta-adrenoceptor blocker metoprolol tartrate was initiated in the hypertensive men. Seven years of antihypertensive treatment resulted in (1) normalization of central and peripheral hemodynamic variables, (2) reversal of left ventricular hypertrophy in proportion to achieved blood pressure control, (3) normalization of systolic wall stress and a well-preserved systolic left ventricular function, (4) normalization of diastolic left ventricular function, and (5) normalization of increased microalbuminuria and a decrease in renal vascular resistance, with no change in glomerular filtration rate compared with control subjects. In conclusion, the findings strongly indicate that regression of cardiovascular structural changes can be achieved with long-term antihypertensive treatment.

Drug Therapy, Combination↗
PubMed1988

Different patterns of cellular sodium turnover in essential hypertension.

Erythrocyte sodium turnover was studied in 22 men aged 56 years who had been treated for hypertension for 7 years. Investigations were performed during treatment, and 1 and 4 weeks after withdrawal of therapy, and when hypertension had returned (blood pressure greater than or equal to 170/105 mmHg). Hypertension returned early in 11 patients (group A) and late in 11 patients (group B). There was no difference in blood pressure, therapy, body weight or peripheral resistance between the groups, but group A had a greater left ventricular mass. Intra-erythrocyte sodium was determined by flame photometry. Sodium influx and the rate constant of sodium efflux were calculated from uptake values of 22Na. In group B the return of hypertension was accompanied by a tendency for an increase in intra-erythrocyte sodium and a decrease in sodium efflux. In group A opposing changes were seen, so that significant differences occurred in sodium efflux and intra-erythrocyte sodium between the groups occurred at the reappearance of hypertension. The results are compatible with the appearance of a membrane abnormality in patients with a slow return of hypertension, whereas other mechanisms, e.g. increased sympathetic activity, may be associated with the more rapid rise in blood pressure in the other group.

Antihypertensive Agents↗