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Biomedical subjects

L Rydén

Publications and source records attributed to L Rydén.

At least 19 recordsLinked to original sources
PubMed1992

Effects of the early administration of enalapril on mortality in patients with acute myocardial infarction. Results of the Cooperative New Scandinavian Enalapril Survival Study II (CONSENSUS II)

BACKGROUND: Long-term administration of angiotensin-converting--enzyme (ACE) inhibitors has been shown to improve survival in patients with symptomatic left ventricular failure and to attenuate left ventricular dilatation in patients with myocardial infarction. We studied whether mortality could be reduced during the 6 months after an acute myocardial infarction with use of the ACE inhibitor enalapril. METHODS: At 103 Scandinavian centers patients with acute myocardial infarctions and blood pressure above 100/60 mm Hg were randomly assigned to treatment with either enalapril or placebo, in addition to conventional therapy. Therapy was initiated with an intravenous infusion of enalapril (enalaprilat) within 24 hours after the onset of chest pain, followed by administration of oral enalapril. RESULTS: Of the 6090 patients enrolled, 3046 were assigned to placebo and 3044 to enalapril. The life-table mortality rates in the two groups at one and six months were not significantly different (6.3 and 10.2 percent in the placebo group vs. 7.2 and 11.0 percent in the enalapril group, P = 0.26). The relative risk of death in the enalapril group was 1.10 (95 percent confidence interval, 0.93 to 1.29). Death due to progressive heart failure occurred in 104 patients (3.4 percent) in the placebo group and 132 (4.3 percent) in the enalapril group (P = 0.06). Therapy had to be changed because of worsening heart failure in 30 percent of the placebo group and 27 percent of the enalapril group (P less than 0.006). Early hypotension (systolic pressure less than 90 mm Hg or diastolic pressure less than 50 mm Hg) occurred in 12 percent of the enalapril group and 3 percent of the placebo group (P less than 0.001). CONCLUSIONS: Enalapril therapy started within 24 hours of the onset of acute myocardial infarction does not improve survival during the 180 days after infarction.

Administration, Oral↗
PubMed1992

Selective adsorption of immunoglobulins and glucosylated proteins on phenylboronate-agarose.

Aminophenylboronate-substituted agarose in 20 mM N-2-hydroxyethylpiperazine-N'-2-ethanesulphonic acid, pH 8.5, selectively adsorbs immunoglobulins and complement factors C3 and C4 from human serum. The selectivity of binding is strongly influenced by the presence of magnesium chloride in the sample buffer. Adsorbed immunoglobulins are quantitatively eluted by sorbitol, but only partially by ethylene glycol or methylcellosolve. Aniline-agarose of a similar degree of substitution shows only weak adsorption of serum proteins under similar experimental conditions, thus indicating the important contribution of the boronate moiety to this interaction. Immunoglobulin adsorption seems not to be due to the cis-diol complexation used extensively for the chromatographic determination of non-enzymatically glucosylated proteins. Hydrophobic and pi-pi interactions with the aromatic structure of the ligand seem also to contribute to protein binding. The behaviour of aminophenylboronate-liganded agarose is, in some respects, rather similar to that of the so-called "thiophilic adsorbents".

Adsorption↗
PubMed1992

Twenty-four hour blood pressure profiles in hypertensive patients following various formulations and dosage regimens of felodipine.

The blood pressure lowering capacity of felodipine administered either as extended release tablets once or twice daily or as plain tablets twice daily has been compared in a double-blind, three-way cross-over study in 16 hypertensive patients. All the patients were on long-term treatment with 10 or 20 mg felodipine daily and other antihypertensive therapy (mainly beta-blockers) was allowed if it was kept unchanged. Non-invasive blood pressure and heart rate recordings were obtained throughout 24 hour periods using an Accutracker ambulatory system. The 24 h mean systolic and diastolic blood pressures after extended release tablets o.m. did not differ significantly from those after extended release tablets b.d. or plain tablets b.d. There was a tendency for the extended release tablets given o.m. to reduce blood pressure somewhat more in the morning, and for the extended release tablets b.d. to reduce blood pressure more during the night than the other treatments. Mean 24 h heart rate after all treatments was comparable. Manual recordings confirmed these results. Blood pressure was well-controlled throughout the 24 h period by all three treatments. The extended release tablets tended to give less extreme plasma concentrations of felodipine. This may be of value for patients with adverse vasodilator effects. For a majority of hypertensive patients the adequacy of blood pressure control and the simplicity of once daily dosing will favour the extended release tablet given once daily.

Aged↗
PubMed1992

Differential effects of xamoterol and verapamil on ventricular rate regulation in patients with chronic atrial fibrillation.

In a placebo-controlled study the effects on ventricular rate regulation and exercise performance of xamoterol, 100 mg two times a day and 200 mg two times a day, and slow-release verapamil, 240 mg once a day, were assessed in 21 patients with chronic atrial fibrillation. The mean ventricular rate from noon to 6:00 PM was 101 +/- 20 beats/min with placebo, 95 +/- 17 beats/min with xamoterol 100 mg two times a day (not significant), 90 +/- 16 beats/min with xamoterol 200 mg two times a day (p less than 0.001 vs placebo) and 78 +/- 19 beats/min with verapamil (p less than 0.001 vs each other treatment). The mean ventricular rate from midnight to 6:00 AM was 69 +/- 16 beats/min with placebo, increased with xamoterol 100 mg two times a day and 200 mg two times a day to 75 +/- 15 beats/min and 74 +/- 16 beats/min, respectively (p less than 0.001 vs placebo), but decreased with verapamil to 62 +/- 15 beats/min (p less than 0.001 vs each other treatment). The number of ventricular pauses greater than 2.0 seconds was increased by verapamil (p less than 0.05). All active treatments reduced exercise ventricular rates (p less than 0.001), but the decrease was more pronounced with verapamil. The anaerobic threshold was reached significantly earlier with verapamil than with placebo (72 +/- 32 W vs 79 +/- 37 W; p less than 0.01). Xamoterol is preferable to verapamil for treatment of patients with chronic atrial fibrillation who exhibit both bradycardia at rest and excessive tachycardia during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗
PubMed1992

Aortic valve replacement in octogenarians with aortic stenosis: a case-control study.

OBJECTIVES: This study was designed to compare the results of aortic valve replacement in patients greater than or equal to 80 years old with those in patients 65 to 75 years old. BACKGROUND: Aortic valve replacement may be potentially more complicated and require the use of more resources when performed in octogenarians rather than in younger patients. Few hard data on this possibility are available. METHODS: The study group comprises all 44 patients greater than or equal to 80 years old (mean age 82 years) who underwent aortic valve replacement at our institution between January 1981 and July 1989. A control group of 83 patients with a mean age of 70 years was matched with the study group for gender and approximate date of valve replacement. Before operation, 86% of the older patients versus 36% of the younger patients were in New York Heart Association functional class III or IV (p less than 0.001). Data were retrospectively collected from hospital records and a self-assessment telephone interview was conducted. RESULTS: The early mortality rate was 14% in the older group versus 4% in the younger group (p = 0.045). The duration of respirator support, intensive care and the total duration of the hospital stay did not differ significantly between groups. The incidence of postoperative low cardiac output syndrome was higher in the older group (p = 0.049), but the incidence of late valve-related complications was similar in the two groups. The 2-year survival rate (including data on patients who died early) was 73% in the older group and 90% in the younger group (p = NS). Six months postoperatively all patients but one were in functional class I or II. CONCLUSIONS: Although the patients greater than or equal to 80 years old had a poorer preoperative status than that of younger patients, aortic valve replacement in this group did not require more use of hospital resources and resulted in a clinical improvement comparable to that of younger patients.

Age Factors↗
PubMed1992

Effects of recombinant human extracellular-superoxide dismutase type C on myocardial infarct size in pigs.

The efficacy of human extracellular-superoxide dismutase type C (EC-SOD C) to limit infarct size after ischemia and reperfusion was explored and compared to that of EC-SOD C combined with catalase (CAT) and to that of CAT alone. EC-SOD C binds to heparan sulphate proteoglycan on the cell surfaces. Thirty-two pigs were subjected to 45 min of myocardial ischemia followed by 4 h of reperfusion. Control pigs (group A; n = 8) received 300 mL of saline into the great cardiac vein during a 30-min period started 5 min prior to reperfusion; pigs in group B (EC-SOD C; n = 8) got 16.6 mg of EC-SOD C; pigs in group C (EC-SOD C + CAT; n = 8) got 16.6 mg of EC-SOD C together with 150 mg of CAT. Pigs in group D (CAT; n = 8) received 150 mg of CAT. In groups B, C, and D, the drug was dissolved in saline and infused into the great cardiac. Infarct size expressed as percent of area at risk was smaller in groups B (14.5 +/- 16.7%) and C (40.8 +/- 13.3%) than in groups A (78.8 +/- 8.6%) and D (67.2 +/- 18.6%; p less than .05). Creatine kinase (CK) activity in ischemic myocardium was higher in groups B (1740 +/- 548 U/g) and C (1729 +/- 358 U/g) than in groups A (1184 +/- 237 U/g) and D (1251 +/- 434 U/g; p less than .05). There was an inverse relation (r = -.83) between infarct size and CK content. The EC-SOD C infusions resulted in only minimal increases in plasma SOD activities. In conclusion, the presence of SOD on the cell surfaces is of importance in the prevention of reperfusion injury rather than circulating SOD.

Animals↗
PubMed1992

Effects of recombinant human extracellular-superoxide dismutase type C on myocardial reperfusion injury in isolated cold-arrested rat hearts.

The efficacy of recombinant human extracellular-superoxide dismutase type C (EC-SOD C) on myocardial reperfusion injury was explored in hypothermically arrested rat hearts, as was its site of action. Forty isolated working rat hearts were subjected to 30 min of global ischemia followed by 30 min of reperfusion. The hearts were arrested by the administration of 10 mL of cold perfusate at the onset of ischemia. At the same time, they were randomly assigned to one of five groups; A: cold perfusate only; B: cold perfusate + EC-SOD C 10.4 mg/L (30,000 U/L); C: cold perfusate+bovine CuZn-SOD 7.5 mg/L (30,000 U/L); D: cold perfusate + EC-SOD C 10.4 mg/L + heparin 50,000U/L; E: cold perfusate + heparin 50,000 U/L. Heparin was given to prevent binding of EC-SOD C to endothelial cell surfaces. Left ventricular function was studied before ischemia and at the end of reperfusion. Percent recovery of maximal left ventricular dP/dt after reperfusion was more pronounced in group B (109 +/- 24%; p less than .05) than in groups A (42 +/- 40%), C (47 +/- 36%), D (44 +/- 33%) and E (58 +/- 25%). Likewise, percent recovery of the double product (heart rate x systolic left ventricular pressure) was better in group B (104 +/- 18%; p less than .05) than in the other groups (A: 47 +/- 37%, C: 49 +/- 36%, D: 50 +/- 35%, E: 69 +/- 31%). Compared to the preischemic level, creatine kinase increased significantly in the coronary effluent after reperfusion in groups A, C, D, and E, but not in group B. The results suggest that EC-SOD C, which attaches to the endothelial cell surfaces, might be particularly effective as protection against myocardial reperfusion injury when given together with cardioplegic solution.

Animals↗
PubMed1992

Efficacy of epanolol versus metoprolol in angina pectoris: report from a Swedish multicentre study of exercise tolerance.

The efficacy of epanolol vs. metoprolol in stable angina pectoris was compared in 114 patients recruited to a randomized double-blind cross-over study, consisting of a 4-week period on each drug. Epanolol (200 mg) or metoprolol (200 mg) was administered daily. Bicycle ergometry was performed at the end of each treatment period. The maximum workload was 134 +/- 18 W on epanolol and 133 +/- 37 W on metoprolol (NS). Values for resting heart rate (epanolol, 72 +/- 11 beats min-1; metoprolol, 64 +/- 12 beats min-1; P less than 0.001), systolic blood pressure (epanolol, 143 +/- 21 mmHg; metoprolol, 137 +/- 21 mmHg; P less than 0.05) and diastolic blood pressure (epanolol, 88 +/- 10 mmHg; metoprolol, 84 +/- 11 mmHg; P less than 0.01) were all higher on epanolol treatment. During exercise, the increase in heart rate and blood pressure was of similar magnitude during the two treatment periods, and these parameters did not differ significantly at the last identical workload. The rating of chest pain, fatigue and dyspnoea did not differ between the two drugs during submaximal or maximal exercise. In conclusion, 200 mg of epanolol and metoprolol have similar efficacy with regard to exercise tolerance. As expected from the partial agonist activity present in epanolol but not in metoprolol, the former drug resulted in a higher heart rate and blood pressure at rest. The observed increase in these parameters during exercise was similar for both drugs.

Adrenergic beta-Antagonists↗
PubMed1992

Quality-of-life in patients treated with atrioventricular synchronous pacing compared to rate modulated ventricular pacing: a long-term, double-blind, crossover study.

To investigate whether the preservation of atrioventricular (AV) synchronization matters for quality-of-life during pacemaker treatment we assessed 17 consecutive patients with high degree AV block and preserved sinus node function in a double-blind, long-term crossover study. A questionnaire with regard to cardiovascular symptoms, sleep disturbances, cognitive functioning, physical ability, social interaction, emotional functioning, and self-perceived health was completed after 2 months of atrial synchronous (DDD) and rate modulated ventricular pacing (VVI,R), respectively. A significant improvement in shortness of breath, dizziness and palpitations as well as an improvement of cognitive functioning was observed during DDD pacing. Nine patients preferred the DDD mode and three the VVI,R mode. The remaining five patients did not express any preference. The preference for the DDD mode was explained by a significant reduction of cardiovascular symptoms and an improved self-perceived health, physical ability, and psychological well-being during DDD pacing. All differences in quality-of-life parameters between the two modes of pacing favored the DDD mode and no adverse effects of this mode were found. Thus, the maintenance of AV synchrony adds further symptomatic relief compared to rate increase alone. The results indicate that DDD pacing is the preferred mode of pacing in patients with high degree AV block and preserved sinus node function.

Cardiac Pacing, Artificial↗
PubMed1992

A double-blind study of submaximal exercise tolerance and variation in paced rate in atrial synchronous compared to activity sensor modulated ventricular pacing.

To assess the variation in paced rate during everyday activity and the importance of atrioventricular synchronization (AV synchrony) for submaximal exercise tolerance, atrial synchronous (DDD) and activity rate modulated ventricular (VVI,R) pacing were compared in 17 patients with high degree AV block. The patients were randomly assigned to either mode and evaluated by treadmill exercise to moderate exertion and by 24-hour Holter monitoring after 2 months in the DDD and VVI,R modes, respectively. At the end of the study, the patients were programmed to the pacing mode corresponding to the preferred study period. During the treadmill test, the mean exercise time to submaximal exertion (Borg 5/10), exertion ratings and respiratory rate did not differ between pacing modes despite a significantly lower ventricular rate in the VVI,R mode. The atrial rate during VVI,R pacing was significantly higher than the ventricular rate, but did not differ from the ventricular rate during DDD pacing. There was a diurnal variation in paced rate in both pacing modes. Paced ventricular rate was, however, higher and variation in paced rate greater in DDD compared to VVI,R pacing. Nine patients preferred the DDD mode, three patients preferred the VVI,R mode, while five subjects did not express any preference. The results from this study indicate that the variation in paced rate during activity sensor-driven VVI,R pacing does not match that during DDD pacing neither during everyday activities nor during submaximal treadmill exercise. Nevertheless, no differences in exercise time, Borg ratings, and respiratory rate during submaximal exercise were found. Thus, for most patients with high degree AV block, DDD and VVI,R pacing seem equally satisfactory for submaximal exercise.

Cardiac Pacing, Artificial↗
PubMed1992

Holter documented sudden death in a patient with an implanted defibrillator.

A 68-year-old man with recurrent attacks of monomorphic ventricular tachycardia (VT) received a pacer cardioverter defibrillator featuring antitachycardia pacing and cardioversion/defibrillation. Over 300 episodes of VT were successfully terminated by antitachycardia pacing. During Holter monitoring the patient experienced supraventricular tachycardia with delivery of multiple antitachycardia pacing, cardioversion, and defibrillation therapies ending with the death of the patient. The following factors played a role in the unfortunate outcome of this patient: 1. triggering of VT therapy by an unexpected high sinus rate; 2. atrial fibrillation induced by cardioversion therapy; 3. a gradual and continuous increase in rate during atrial fibrillation possibly caused by repeated VT and ventricular fibrillation therapies and/or by a thrombus, found at autopsy, in a bypass graft; and 4. the limited ability of presently available defibrillators to distinguish between ventricular and supraventricular arrhythmias.

Aged↗
PubMed1992

Longevity in patients with high degree atrioventricular block paced in the atrial synchronous or the fixed rate ventricular inhibited mode.

Survival in patients paced for high degree AV block has been demonstrated to be influenced by underlying cardiac disease in particular congestive heart failure. One previous study has suggested that dual chamber pacing may improve the vital prognosis for such patients. To investigate this, 74 patients treated with rate adaptive atrial synchronous (VDD) and 74 patients treated with VVI pacemakers for high degree AV block, were retrospectively studied for a mean of 5.4 years by life-table analysis. The two groups had an equal distribution of age, sex, date of pacemaker implantation, and concomitant cardiovascular diseases. Total mortality and estimated survival did not differ between the two groups. The estimated survival in the VDD group at 1, 3, and 5 years for patients without and with congestive heart failure was 94%, 86% and 78%, and 92%, 83% and 72%, respectively. In the VVI group the corresponding values were 95%, 90%, and 83% for patients without congestive heart failure and 82%, 64%, and 47% for those with congestive heart failure (P = 0.008). Compared to the expected survival rate of the general Swedish population, only the VVI group with congestive heart failure, had an excess mortality (P = 0.007). Patients with high degree AV block have a fairly normal vital prognosis irrespective of pacing mode. The prognosis for patients with congestive heart failure was negatively affected by VVI pacing. Thus, for patients with congestive heart failure the choice of pacing mode is of vital importance, whereas for patients without congestive heart failure, other factors such as feeling of well-being and exercise capacity should decide the final choice of pacing mode.

Aged↗