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Biomedical subjects

K Swedberg

Publications and source records attributed to K Swedberg.

At least 181 records · Page 10Linked to original sources

Variability, prediction and prognostic significance of chest pain in acute myocardial infarction.

The variability of chest pain is described in 389 patients with acute myocardial infarction. Whereas 17% were free from severe pain after arrival in hospital, 11% required more than 10 analgesic injections. In 27% of the series analgesics were given more than 24 h after arrival in hospital. Predictors for the severity of chest pain were the rate-pressure product and degree of chest pain soon after arrival in hospital as well as electrocardiographic signs of myocardial infarction at entry. Patients with more severe chest pain had a higher 2-year mortality rate and a higher incidence of ventricular fibrillation and congestive heart failure during hospitalization.

Analgesia↗

Hemodynamic effects of metoprolol in acute myocardial infarction. A randomized, placebo-controlled multicenter study.

The central hemodynamic effects of metoprolol in acute myocardial infarction have been studied in a multicenter, double-blind, randomized trial. One hundred and ninety patients with acute myocardial infarction not previously on beta blockers with heart rate greater than 65 beats/min and blood pressure greater than 105 mm Hg and without clinical signs of serious heart failure were included. After insertion of a pulmonary artery catheter, patients were randomized to metoprolol, 15 mg intravenously, and 50 mg 4 times a day orally (n = 95) or placebo (n = 95) with a mean delay of 7.2 hours. Hemodynamic measurements were made at baseline and repeatedly during 24 hours. Heart rate, systolic blood pressure and cardiac index were all immediately reduced by 10 to 20% in the metoprolol group and the difference compared with placebo was maintained throughout the 24 hours (p less than 0.001). Pulmonary capillary wedge pressure (PCWP) in the metoprolol group increased from 13.7 +/- 6.7 to a peak of 15.5 +/- 5.5 mm Hg 30 minutes after injection. The difference compared with placebo was maintained for 8 hours (p less than 0.01). This increase was seen only in the patient group with initial PCWP below the median of 13 mm Hg. In patients with initial PCWP above the median a continuous decrease was observed in both the placebo and metoprolol groups. Thus high initial PCWP was not associated with intolerance to metoprolol. Based on hemodynamic measurements tolerance to metoprolol was good.

Aged↗

Myocardial catecholamine balance during angina: effects of calcium entry blockers, verapamil and nifedipine.

To evaluate the effects of calcium entry blocking agents on cardiac sympathetic tone during angina pectoris, arterial and coronary sinus (CS) norepinephrine (NE) and epinephrine (E) concentrations and CS blood flow were determined at rest and during pacing-induced angina, both before and after verapamil in nine patients and after nifedipine in nine patients, all of whom had fixed obstructive coronary artery disease. Resting arterial NE and E concentrations and myocardial NE release and E uptake remained unchanged during angina before verapamil and nifedipine, suggesting unaltered systemic and cardiac sympathetic tone and myocardial E handling. Following verapamil and nifedipine, arterial NE and E concentrations remained unchanged. After verapamil, net myocardial NE release increased from 16,072 +/- 18,881 to 35,520 +/- 30,595 at preverapamil angina rate (p less than 0.01) and to 39,643 +/- 29,728 pg/min at postverapamil angina rate (p less than 0.01). NE release after nifedipine increased from -4207 +/- 8898 to 10,988 +/- 30,711 (p less than 0.05) at prenifedipine angina rate and to 19,942 +/- 26,644 pg/min (p less than 0.05) at postnifedipine angina rate. NE release was independent of changes in CS flow after verapamil or nifedipine. E uptake after verapamil and nifedipine remained unchanged. Although the precise mechanism is not known, myocardial alpha-adrenergic receptor blockage with verapamil and nifedipine remains a possible explanation for increased myocardial NE release.

Aged↗

Endogenous catecholamine levels in chronic heart failure. Relation to the severity of hemodynamic abnormalities.

Plasma free epinephrine, norepinephrine, and dopamine concentrations were determined in 48, 63, and 45 patients, respectively, with overt congestive heart failure, and compared with those in 26 patients with stable angina but without heart failure. Systemic hemodynamic values were determined to assess the severity of heart failure. Arterial epinephrine levels were not different between patients with heart failure (73 +/- 92 pg/ml) and patients without heart failure (55 +/- 73 pg/ml). In patients with congestive heart failure, norepinephrine (665 +/- 510 pg/ml, mean +/- SD) and dopamine (407 +/- 405 pg/ml) levels were significantly higher than in patients with stable angina without heart failure (norepinephrine 184 +/- 136 pg/ml, p less than 0.001, and dopamine 197 +/- 259 pg/ml, p less than 0.02). However, in patients with congestive heart failure, the plasma norepinephrine levels did not correlate with cardiac index (r = 0.21, p = NS), pulmonary capillary wedge pressure (r = 0.11, p = NS), mean arterial pressure (r = 0.11, p = NS), or systemic vascular resistance (r = 0.18, p = NS). Similarly, there was no correlation between dopamine levels and the hemodynamic abnormalities in patients with congestive heart failure. These findings suggest that although endogenous norepinephrine and dopamine levels are frequently elevated in patients with heart failure, reflecting enhanced sympathetic activity, catecholamine levels do not reflect the severity of heart failure.

Adult↗

ADP-induced platelet aggregation and metoprolol treatment of myocardial infarction patients. A controlled study.

The effect of metoprolol on platelet aggregation was investigated in a group of postmyocardial infarction (MI) patients. The study was double-blind and included 63 subjects; 30 patients were maintained on metoprolol and 33 received placebo treatment. Adenosine diphosphate (ADP)-induced platelet aggregation was carried out in each subject close to 4 weeks after the acute MI. It was demonstrated that metoprolol as compared to placebo did not influence ADP-induced platelet aggregation in the present clinical setting.

Adenosine Diphosphate↗

Tolerability to treatment with metoprolol in acute myocardial infarction in relation to age.

A double-blind trial with the beta 1-selective blocker metoprolol in suspected acute myocardial infarction and during 3 months' follow-up included 1395 patients, aged 40-74 years, 698 on metoprolol and 697 on placebo. In order to further evaluate the tolerability to beta-blockade in the elderly, the total series was divided into 2 groups according to median age (61 years) and into quartiles, the lowest quartile (40-57 years) being compared with the highest (67-74 years). The decrease in heart rate and systolic blood pressure after intravenous metoprolol in the acute phase was similar in the elderly and the younger patients. Hypotension was observed more often in the metoprolol-treated than in the placebo-treated younger patients, while no difference was observed in the elderly. Bradycardia was observed more often in the metoprolol group in both age groups, while there was no difference regarding the incidence of congestive heart failure in either the younger or in the elderly patients. The effect on mortality, serious ventricular arrhythmias and chest pain seemed to be similar in different age groups. From the present series we conclude that hemodynamic reactions and tolerability to beta-blockade can be expected to be similar in elderly and younger patients.

Adult↗

Rupture of the myocardium. Occurrence and risk factors.

The occurrence of myocardial rupture was studied in a well defined unselected population of patients with acute myocardial infarction, and the group of patients who died of rupture of the heart were compared with two control groups. Of a total of 3960 patients, 1746 (44%) fulfilled the diagnostic criteria for acute myocardial infarction. Rupture was defined solely on the basis of the presence of a pathological passage through part of the myocardium, either the free wall of the left ventricle or the septum, found at necropsy or during operation. Two controls were selected for each patient and matched for age and sex, one (control group A) with acute myocardial infarction having died in hospital but not of rupture (non-rupture cardiac death) and one (control group B) with acute myocardial infarction having survived the hospital stay. Necropsy was performed in 75% of all fatal cases with acute myocardial infarction. The total hospital mortality was 19%, the highest mortality being among women over 70 years (29%). Ruptures (n = 56) were found in 17% of the hospital deaths, or 3.2% of all cases of acute myocardial infarction. Women aged less than 70 had the highest incidence of rupture, 42% of deaths being due to rupture. The mean age for patients with rupture and controls was 70.5 years. The median time after admission to death was approximately 50 hours for patients and control group A. Thirty per cent of the patients with rupture occurred within 24 hours of the initial symptoms occurring. Angina and previous acute myocardial infarction were more common among control group A. Patients with rupture and control group B were mostly relatively free of previous cardiovascular or other diseases (chronic angina pectoris ( > 2 months) and previous myocardial infarction). Sustained hypertension during admission to the coronary care unit was more common in patients than in control group A. Hypotension and shock were more common among control group A. Most (79%) of the patients who subsequently ruptured did not receive any corticosteroids at all during the hospital stay. Severe heart failure and antiarrhythmic treatment were more uncommon among patients than among control group A. Patients with rupture received analgesics approximately three times a day throughout their stay. Control group B received analgesics mostly during the first 24 hours. Thus female patients, patients with first infarcts, and patients with sustained chest pain should be investigated for the possibility of rupture. As many as one third (32%) of ruptures may be subacute, and therefore time is available for diagnosis and surgery.

Aged↗

Comparison of myocardial catecholamine balance in chronic congestive heart failure and in angina pectoris without failure.

To evaluate myocardial catecholamine balance in heart failure, systemic hemodynamics, coronary sinus blood flow, and arterial and coronary sinus venous norepinephrine (NE) and epinephrine (E) concentrations were determined in 30 patients with chronic left ventricular failure (CHF), and in 25 patients with angina pectoris (AP) but without heart failure. In the group with CHF, stroke work index was lower (CHF 20 +/- 9, AP 53 +/- 13 g-m/m2, p less than 0.001) and pulmonary capillary wedge pressure higher (CHF 28 +/- 8, AP 11 +/- 4 mm Hg, p less than 0.001), indicating depressed left ventricular function. Coronary sinus blood flow was similar in 2 groups (CHF 97 +/- 70, AP 73 +/- 32 ml/min, difference not significant). In the group with CHF, arterial (634 +/- 582 pg/ml) and coronary sinus venous (1,038 +/- 1,014 pg/ml) NE concentrations were significantly higher than in the group with AP (arterial 185 +/- 135, coronary sinus 231 +/- 167 pg/ml, p less than 0.001). The net myocardial NE release in patients with CHF was approximately 20 times higher than that in patients with AP (CHF 38,548 +/- 48,622, AP 2,245 +/- 10,242 pg/min, p less than 0.001). Arterial E and myocardial E uptake was similar in both groups. Although mechanisms for increased myocardial net NE release remains unknown, it probably represents enhanced cardiac sympathetic tone in response to heart failure.

Adult↗

Göteborg Metoprolol Trial: enzyme-estimated infarct size.

In 1,375 patients serum activity of heat-stable lactate dehydrogenase (LD; E.C.1.1.1.27.) was analyzed every twelfth hour for 48 to 108 hours. The mean maximum LD activity was 11.1 +/- 0.4 mu kat X 1(-1) in the metoprolol group vs 12.4 +/- 0.5 mu kat X 1(-1) in the placebo group (p = 0.054). In patients in whom treatment was started 12 hours or less after the onset of pain, a 17% reduction in LD activity was observed (p = 0.009) and similar results were found in patients randomized 8 hours or less. Groups in which the effect after metoprolol treatment was more pronounced were those with an initially higher heart rate and also those with anterior myocardial infarction.

Aged↗

Göteborg Metoprolol Trial: electrocardiographically estimated infarct size.

In 236 patients with anterior myocardial infarction (MI), infarct size was estimated by analyzing the R- and Q-wave amplitude in 24 precordial leads 4 days after randomization. In 254 patients with inferior MI, the final R- and Q-wave amplitude was evaluated in leads II, III and aVF. Electrocardiographic signs of a smaller MI were observed in anterior MI in the metoprolol group compared with the placebo group when treatment was started 12 hours or less after the onset of pain, but no difference was found when treatment was started later. There was no sign of an effect of metoprolol in inferior MI. An immediate reduction in ST-segment elevation was observed after metoprolol treatment regardless of infarct localization or delay between the onset of pain and treatment.

Clinical Trials as Topic↗

Göteborg Metoprolol Trial: effects on arrhythmias.

During the initial hospitalization, ventricular fibrillation (VF) developed in 6 metoprolol-treated patients (0.9%) vs 17 placebo-treated patients (2.4%) after inclusion in the study (p = 0.035). There were 6 episodes of VF in the metoprolol group compared with 41 episodes in the placebo group (p less than 0.001). During the same period, 14 metoprolol-treated patients had treated ventricular tachycardia vs 26 placebo-treated patients (p = 0.076). Similar favorable results were found when the incidence of severe ventricular arrhythmias during the first rehospitalization within the 3-month double-blind treatment period was analyzed.

Adult↗

Göteborg Metoprolol Trial: design, patient characteristics and conduct.

The Göteborg Metoprolol Trial was a double-blind, placebo-controlled, stratified trial aimed at evaluating the effect of the beta 1-selective blocker, metoprolol, in suspected acute myocardial infarction and during 2 years of follow-up. The primary end-point was 3-month mortality (blind treatment period). Secondary end-points were 2-year mortality, indirect signs of infarct size, chest pain, arrhythmias and tolerability. The entry criteria were fulfilled in 2,802 patients, 1,395 of whom were included in the trial. Treatment started as soon as possible after arrival in hospital with intravenous administration followed by oral treatment for 3 months. All patients were randomized 48 hours or less after estimated onset of infarction and 69% were randomized at 12 hours or less. The blind treatment had to be withdrawn in 19% of all randomized patients before the end of the 3-month follow-up.

Aged↗

Göteborg Metoprolol Trial: effects on chest pain.

The effect of metoprolol on chest pain was compared with that of placebo in all randomized patients. The pain score before and 15 minutes after the injection of trial medication was registered and a reduction in chest pain was observed in the metoprolol group. Increasing chest pain after blind injection was observed in only 16 and 9 patients from the placebo and metoprolol groups, respectively. Comparison with the placebo as well as detailed analysis of clinical data revealed that in these patients the increasing pain could not be explained by coronary spasm evoked by beta-blockade. Similarly, metoprolol did not exhibit any unfavorable effect on the 14 patients who were withdrawn (together with the 28 patients given placebo) from blind treatment due to angina pectoris. Either metoprolol does not induce coronary vasospasm or spasm does not play a role in these patients with definite and suspected acute myocardial infarction as well as unstable angina pectoris. Metoprolol reduced the need for analgesics during the first 4 days and shortened the duration of pain. The effects were similar in patients with early and late treatment, but may depend on initial heart rate, blood pressure and site of infarction.

Administration, Oral↗

Göteborg Metoprolol Trial: mortality and causes of death.

During the 3-month blind treatment period there were 40 deaths in the metoprolol group compared with 62 deaths in the placebo group (p = 0.024). During the first year (after 3 months the 2 groups were treated similarly) there were 64 deaths in the metoprolol group vs 93 in the placebo group (p = 0.017) and during 2 years 92 patients died in the metoprolol group vs 120 in the placebo group (p = 0.043). The relative incidence of different causes of death did not differ significantly between the 2 treatment groups, indicating that metoprolol reduced all causes of death to the same extent as its effect on overall mortality.

Aged↗

Audibility of an artificial third heart sound in relation to its frequency, amplitude, delay from the second heart sound and the experience of the observer.

The possibility of detecting synthetic third heart sounds was studied. A special unit was used that added a sound to a previously recorded phonocardiogram. The sound could be changed in frequency, amplitude and delay from the second heart sound. Four groups of observers--cardiologists, residents, nurses and students--listened to 32 random examples. Detection rate increased with experience of the observer (p less than 0.0001) as well as with amplitude (p less than 0.0001), frequency (p less than 0.0001) and delay of the sound (p less than 0.05). The sensitivity was highest among the cardiologists, but the specificity was not different between the groups. Data from this study indicate that the audibility of the third heart sound depends on several important factors. The sound should usually be audible, but variability of results were considerable even among experienced cardiologists. A quantified phonocardiographic recording should be used for validation.

Cardiology↗

Intravenous and oral prenalterol in congestive heart failure. Effects on systemic and coronary hemodynamics and myocardial catecholamine balance.

Systemic and coronary hemodynamic effects of prenalterol, a beta-1 receptor agonist, were determined in patients with chronic congestive heart failure, initially after intravenous administration (10 patients) and then after oral administration (eight patients). Cardiac index increased by 33 percent and 30 percent after intravenous and oral prenalterol, respectively. The increase in stroke volume index and stroke work index and decrease in pulmonary capillary wedge pressure and systemic vascular resistance were not significant. Myocardial oxygen consumption and coronary sinus blood flow increased in the majority of patients, although these changes were not statistically significant. There were no significant changes in transmyocardial norepinephrine or epinephrine balance. The systemic and coronary hemodynamic effects of both intravenous and oral prenalterol were similar. Major side effects included sudden death (two patients) and hypotension and bradycardia (three patients) during oral prenalterol treatment. It is concluded that improved left ventricular function following both intravenous and oral prenalterol may be associated with increased myocardial oxygen consumption, and serious adverse effects may occur during prenalterol therapy.

Administration, Oral↗