Biomedical subjects

B O Olofsson

Publications and source records attributed to B O Olofsson.

At least 19 recordsLinked to original sources

PubMed1999

Ischemic stroke. Impact of a recent myocardial infarction.

BACKGROUND AND PURPOSE: The risk of ischemic stroke is increased after a myocardial infarction. We quantified the stroke risk and evaluated ischemic stroke characteristics after an acute myocardial infarction. METHODS: A case-control study including patients with first-ever stroke was undertaken. Cases (n=103) were recorded prospectively in the population-based Northern Sweden World Health Organization Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) study. Two controls per case with a stroke but without a recent myocardial infarction were matched for age, sex, and year of stroke onset. RESULTS: The sudden onset of neurological symptoms (76.7% versus 54.9%, P<0.001), impairment of consciousness (35.0% versus 18.4%, P<0.01), and a progression in neurological deficits (19.4% versus 8.7%, P<0.01) were more common in cases, while the onset of stroke during sleep was rarer in cases (6.8% versus 21.4%, P<0.01). In cases and controls, the clinical subclasses of stroke were as follows: total anterior circulation infarcts, 51.5% versus 37.9% (P<0.05); partial anterior circulation infarcts, 28.2% versus 26.7% (P=NS); lacunar infarcts, 4.8% versus 27.2% (P<0.001); and posterior circulation infarcts, 15.5% versus 8.2% (P=0.051). During the first 28 days after myocardial infarction, the daily rate of stroke declined rapidly from approximately 9 to 1 stroke per 10 000 myocardial infarction patients compared with an age-adjusted average daily stroke rate of 0.14 per 10 000 in the MONICA population. CONCLUSIONS: We conclude that the clinical characteristics of the stroke differ between patients with and without a recent myocardial infarction. The risk of a first-ever ischemic stroke is highest during the first few days after a myocardial infarction, but it then declines rapidly, and the absolute number of stroke events is low.

Acute Disease↗

PubMed1998

Spectral analysis of heart rate variability in patients with irritable bowel syndrome.

BACKGROUND: Autonomic dysfunction, both adrenergic and cholinergic, has been associated with the irritable bowel syndrome (IBS). The accuracy of the methods in use, however, has been limited by the need for active co-operation by the patients, with consequent difficulties in standardization. The aim of this study was to investigate the function of the autonomic nervous system in patients with IBS by using spectral analysis of the heart rate variability, an accurate method depending very little on patient cooperation. METHODS: Eighteen patients with IBS were compared with 36 sex- and age-matched controls. Spectral analysis of heart rate variability was performed to quantify sympathetic and parasympathetic nerve activity. RESULTS: The patients with IBS had significantly higher sympathetic activity than controls (P = 0.005). There was no significant (P = 0.308) increase in parasympathetic activity. There were no significant differences in heart rate or blood pressure between the patients and controls. CONCLUSION: Spectral analysis of heart rate variability has been used to assess the function of the autonomic nervous system in patients with IBS. IBS patients have significantly increased symphathetic activity, whereas parasympathetic activity does not differ from that of controls.

Adult↗

PubMed1997

Impact of autonomic neuropathy on circulatory instability during liver transplantation for familial amyloidotic polyneuropathy.

BACKGROUND: Circulatory instability with severe hypotension frequently complicates liver transplantation in patients with familial amyloidotic polyneuropathy. Autonomic dysfunction is found early in the course of the disease by analysis of beat-to-beat heart rate variability (HRV). The aim of the present study was to investigate the impact of autonomic neuropathy on intraoperative circulatory instability during liver transplantation for familial amyloidotic polyneuropathy. METHODS: Twenty-two patients were evaluated at the Department of Medicine, Umea University Hospital, by spectral analysis of HRV and later received liver transplants at Huddinge University Hospital. The low-and high-frequency bands obtained by spectral analysis of HRV in the supine and upright positions, respectively, were used as representative of sympathetic and parasympathetic activity. Circulatory instability during transplantation was defined as a fall in systolic arterial blood pressure below 70 mmHg for more than 5 min during the preanhepatic phase. RESULTS: Both arrhythmia preventing spectral analysis of HRV and a sympathetic variability peak below 2.5 mHz2 were significantly more common among patients with intraoperative circulatory instability (P=0.03 and 0. 004, respectively). A diminished increase in pulse rate when tilting the patients from the supine to the upright position was also more pronounced among patients with circulatory instability (P<0.05). CONCLUSIONS: The majority of patients who will develop circulatory instability with a pronounced fall in arterial blood pressure can be identified by Poincare plots of R-R intervals and spectral analysis of HRV. A low sympathetic peak or arrhythmia precluding spectral analysis of HRV is significantly related to operative circulatory instability.

Amyloid Neuropathies↗

PubMed1997

Impact of liver transplantation on autonomic neuropathy in familial amyloidotic polyneuropathy: an evaluation by spectral analysis of heart rate variability.

OBJECTIVES: To evaluate the impact of liver transplantation on familial amyloidotic polyneuropathy type I (FAP) patients' autonomic neuropathy. DESIGN: An open study. SETTING: A tertiary referral centre. SUBJECTS: Twelve liver-transplanted FAP patients evaluated before and one year or longer after liver transplantation. INTERVENTIONS: Spectral analysis of heart rate variability. The low-frequency band after tilting (sympathetic), and the high-frequency band in supine position (parasympathetic) were analysed, as were the pulse and blood pressure reaction to tilting. Clinical symptoms related to autonomic disturbances were recorded. MAIN OUTCOME MEASURES: Spectral band power for sympathetic and parasympathetic activity. RESULTS: No statistically significant improvements in sympathetic or parasympathetic band power after liver transplantation was found (sympathetic band power: 2.7 (2.2-3.2) before, 2.9 (2.2-3.6) after; parasympathetic 2.0 (1.6-2.4) before and 2.0 (1.7-2.3) after. A significant correlation was noted between orthostatic blood pressure reaction and sympathetic activity before transplantation, but not after the operation. A trend was noted for improved orthostatic blood pressure reaction. Symptomatic improvements in bowel function and orthostatic symptoms were reported by several patients. CONCLUSIONS: Although improvements in autonomic symptoms are reported after liver transplantation, no significant improvement is noted in sympathetic or parasympathetic spectral band power of heart rate variability. However, the follow-up period of 17 months may be too short. Further evaluation after an additional two and four years is needed.

Adult↗

PubMed1996

Assessment of autonomic nerve function in acute intermittent porphyria; a study based on spectral analysis of heart rate variability.

OBJECTIVES: To assess the function of the autonomic nervous system in patients with acute intermittent porphyria by spectral analysis of the heart rate variability. DESIGN: A cross-sectional case-control study. SETTING: Patients were examined at the Primary Health Care Centre, Arjeplog and at Umeå University Hospital, where the controls were also examined. SUBJECTS: Twenty-three patients with acute intermittent porphyria verified by DNA analysis and 92 healthy controls were included. MAIN OUTCOME MEASURES: The mid-frequency band power after tilting was used to evaluate sympathetic function, and the high frequency band power during controlled breathing at 12 breaths min-1 and the mid-frequency band power during controlled deep breathing at 6 breaths min-1 were used to evaluate parasympathetic function. RESULTS: There was no evidence of sympathetic dysfunction in the patients. The mid-frequency band power during controlled deep breathing at 6 breaths min-1 was significantly (P = 0.02) lower in the patient group. CONCLUSIONS: Our findings indicate a parasympathetic dysfunction in patients with acute intermittent porphyria. This may be causally related to sudden cardiac death and the life-threatening arrhythmias which have been observed in this disorder.

Adult↗

PubMed1993

Heart-rate variation: what are we measuring?

Many methods have been proposed during the last two decades for the assessment of autonomic nervous system function by quantification of the heart-rate variation (HRV). Relatively little has been written about the HRV in relation to physiological models of the heart-rate regulation. The integral pulse frequency model (IPFM) is a simple model that describes the genesis of heartbeats under the influence of the autonomic nervous system. By comparing simulated HRV data generated with the IPFM model with data from healthy volunteers we found similarities indicating that the model accurately reflects real data. Furthermore, we found a considerable difference between HRV measurements based on beat-by-beat heart-rate and measurements based on the heartbeat interval. Our results suggest that the commonly used electrocardiographic RR interval representation of heart-rate variation might possess an inherent nonlinear, mean heart-rate-dependent property indicating that analysis directly based on RR intervals can give biased results with respect to the underlying autonomic activity. The conclusions embrace all measurements of variation that are directly based on RR intervals including simple indices as well as higher-level quantification such as spectral analysis.

Adult↗

PubMed1993

Predictive value of tissue plasminogen activator mass concentration on long-term mortality in patients with coronary artery disease. A 7-year follow-up.

BACKGROUND: The fibrinolytic system is part of the defense against thrombotic and cardiovascular events, but so far no study has shown that clinical measurements of fibrinolytic key components such as tissue plasminogen activator (t-PA) or plasminogen activator inhibitor type 1 (PAI-1) have any predictive value beyond 3 years. METHODS AND RESULTS: In 1983 through 1985, 213 consecutive patients with angina pectoris and angiographically verified coronary artery disease were sampled, and the mass concentration of t-PA and the activity of PAI-1 were measured in citrated plasma samples. At a mean follow-up time of 7 years, the all-cause mortality was checked. No patient was lost to follow-up. The data were analyzed by Cox regression, and t-PA mass concentration was found to be the only laboratory risk factor significantly related to mortality in all patients (P < .022) and also in the major subgroup (78% of all patients) subjected to coronary bypass surgery (P < .027). In the latter subgroup, body mass index was also related to mortality. CONCLUSIONS: An increased mass concentration of t-PA is a new risk factor of long-term mortality in patients with angina pectoris and coronary artery stenosis. This paradoxical effect probably reflects increased t-PA levels attributable to enzyme inhibitor complex formation in subjects with increased plasma levels of t-PA inhibitors.

Aged↗

PubMed1991

Tissue plasminogen activator and other risk factors as predictors of cardiovascular events in patients with severe angina pectoris.

The value of measurements of the fibrinolytic factors, tissue plasminogen activator and plasminogen activator inhibitor, for predicting death and non-fatal cardiovascular events was studied in 213 consecutive patients with angiographically documented coronary artery disease. In the course of 4-year follow-up, 47 patients (22.1%) had at least one cardiovascular event. We found the incidence of cardiovascular events to be positively associated with high tissue plasminogen activator antigen concentration, in addition to previous myocardial infarction, low ejection fraction, hypertension, high body mass index and high triglyceride levels. Cholesterol was not found to be associated with cardiovascular events. A high concentration of tissue plasminogen activator antigen thus implies an increased risk of cardiovascular events in patients with severe angina pectoris.

Adult↗

PubMed1991

Assessment of hypothalamic-pituitary function in patients with familial amyloidotic polyneuropathy.

This study was performed to evaluate hypothalamic-pituitary hormone regulation in patients with familial amyloidotic polyneuropathy. Twenty-two patients without clinically overt endocrinological dysfunction were studied. A thyrotropin-releasing hormone test revealed abnormal growth hormone regulation in 9 of 17 (53%) patients, and abnormal prolactin regulation in 9 of 18 (50%) patients. Abnormalities in either growth hormone or prolactin regulation were found in 12 of 17 (71%) patients. Serum somatomedin C levels were normal in all 22 patients. In 3 of 18 (17%) patients the plasma arginine vasopressin levels were low relative to the serum osmolality levels. Thus abnormalities in hypothalamic-pituitary hormone regulation may be common in familial amyloidotic polyneuropathy.

Amyloidosis↗

PubMed1990

Assessment of autonomic nerve function in myotonic dystrophy.

The function of the autonomic nervous system was studied in 23 patients with myotonic dystrophy, from a defined population in northern Sweden with an extremely high prevalence of this disease. Heart rate variability tests showed only minor signs of parasympathetic dysfunction. Blood pressure and plasma noradrenaline measurements in recumbent and upright positions showed no signs of sympathetic neuropathy. Increased plasma levels of noradrenaline was an unexpected finding. Our study does not support the hypothesis that cardiac arrhythmias, orthostatic hypotension, gastrointestinal motility disturbances and urinary bladder dysfunction in myotonic dystrophy are caused by autonomic neuropathy, and we believe that these symptoms should rather be ascribed to a defective function of the target organs.

Adolescent↗

PubMed1990

Cardiac involvement in congenital myotonic dystrophy.

Seven young patients (mean age 19 years 8 months) with congenital myotonic dystrophy and with defined symptoms at birth were investigated by electrocardiography and echocardiography. None had cardiovascular symptoms. Electrocardiograms or echocardiograms or both were abnormal in all patients. Atrioventricular and intraventricular conduction defects were the most common electrocardiographic abnormalities and were seen in five patients. The echocardiographic examinations showed impaired left ventricular systolic function in one patient. Other echocardiographic findings were a small left ventricle and atrium, minor valve defects, and mitral valve prolapse. This study shows that the heart is often affected in young patients with congenital myotonic dystrophy. The specialised conduction system is often affected and so too is the myocardium, causing impaired systolic function.

Adolescent↗

PubMed1990

Reduced levels of tissue plasminogen activator and plasminogen activator inhibitor in plasma of patients with familial amyloidotic polyneuropathy.

Tissue plasminogen activator (tPA) antigen levels and plasminogen activator inhibitor (PAI) activity were measured in the plasma from 23 patients with familial amyloidotic polyneuropathy. Both tPA levels and PAI activity were reduced to about half normal, even when the effects of patient age and body mass index were taken into account. There were higher mean tPA levels and PAI activity in patients with mild disability than in those with moderate or severe disability, but these differences were not statistically significant. There were normal tPA levels after venous occlusion of the upper arm, indicating a normal capacity of vascular endothelium to release tPA. This is the first reported disorder with reduced rather than increased basal tPA and PAI levels. The pathogenetic and clinical significances of these disturbances so far remain obscure.

Adult↗

PubMed1989

Evidence for increased levels of plasminogen activator inhibitor and tissue plasminogen activator in plasma of patients with angiographically verified coronary artery disease.

We studied 234 consecutive patients who underwent coronary angiography because of severe angina pectoris. Tissue plasminogen activator (tPA), plasminogen activator inhibitor (PAI), and lipoprotein Lp(a) were measured in citrated plasma samples. The 214 patients showing significant coronary artery stenosis (greater than 50% reduction of luminal area in any of the great coronary arteries) had higher mean levels of tPA (P less than 0.001) and PAI (P less than 0.01) than a random population sample of similar age. PAI and tPA levels were higher in smokers than in either non-smokers or ex-smokers, and in patients with hypertension tPA was increased. Subjects with blood group A had a higher mean Lp(a) level than subjects with blood group O. There were positive correlations of PAI and tPA levels with serum triglycerides and with body mass index; Lp(a) correlated weakly with plasma fibrinogen concentrations. The findings suggest an impairment of the fibrinolytic system in patients with coronary artery disease, which offers a link between established risk factors and a plausible pathophysiological mechanism, namely thrombus turnover.

Adult↗

PubMed1989

Assessment of thyroid and adrenal function in patients with familial amyloidotic polyneuropathy.

This study was performed to evaluate thyroid and adrenal function in patients with familial amyloidotic polyneuropathy. Twenty-four patients without any clinical overt endocrinological dysfunction were studied. None of the patients showed laboratory evidences of hypo- or hyperthyroidism. A short ACTH-stimulation test was performed in 17 of the patients. A low cortisol response to ACTH stimulation, suggesting adrenocortical insufficiency, was found in four (24%) of the patients, and an intermediate response interpreted as suspected hypofunction was found in three (18%) patients. Low serum dehydroepiandrosterone sulphate levels, suggesting adrenal hypofunction, were found in six (25%) of the patients. We believe that the possibility of glucocorticoid insufficiency should always be considered in patients with familial amyloidotic polyneuropathy.

Adrenal Cortex↗

PubMed1989

Autonomic neuropathy in familial amyloidotic polyneuropathy. A clinical study based on heart rate variability.

Familial amyloidotic polyneuropathy (FAP) is characterized by both sensimotor and autonomic dysfunction. Autonomic disturbance involving the gastrointestinal tract, the urinary bladder, the cardiac conduction system, and the peripheral circulation has been described. In this study simple, non-invasive tests of autonomic function based on heart rate variability were applied to 12 patients with FAP and 12 healthy volunteers. The heart rate variation during normal breathing, deep breathing and during tilt from recumbent to standing position was measured. All tests showed significantly less heart rate variation in patients than in controls and the heart rate variation decreased with increasing severity of neurological disability, but the small number of patients in our study does not allow any further comparison between subgroups. Our study thus indicates impaired cardiovascular autonomic function in patients with FAP and we believe that these findings might also be of importance in other forms of systemic amyloidosis.

Adult↗

PubMed1988

Propafenone versus disopyramide for treatment of chronic symptomatic ventricular arrhythmias. A multicenter study.

The efficacy and safety of propafenone, 150 mg four times daily, were compared with those of disopyramide, 100 mg four times daily, in a randomized single-blind, cross-over study in 38 patients with symptomatic premature ventricular complexes (PVCs). The 24-hour ambulatory ECG, employed for assessing antiarrhythmic efficacy, was analyzed blindly. The median reduction in the number of PVCs was higher with propafenone than with disopyramide (91.4% vs. 63.5%, respectively, p less than 0.01). A reduction of at least 80% was achieved by propafenone in 22 (59%) and by disopyramide in 16 patients (43%) (NS). Ventricular tachycardias (VTs) were abolished by propafenone in eight out of 11, and by disopyramide in five out of nine patients with VTs (NS) a possible proarrhythmic effect was seen in three patients during disopyramide and in one patient during propafenone treatment. Micturition disturbances (p less than 0.001) and a dry mouth (p less than 0.01) were more commonly associated with disopyramide than with propafenone. In conclusion, in the given dosages, propafenone was superior to disopyramide in suppressing PVCs and had fewer side-effects.

Adult↗

PubMed1988

Electrocardiographic findings in myotonic dystrophy.

Sixty five patients with myotonic dystrophy, from a defined population in northern Sweden with an extremely high prevalence of this disease, were examined by electrocardiography. The patients were subdivided into three groups according to the severity of the disease. Abnormal electrocardiograms were found in 6 (35%) patients with mild disease, 12 (50%) patients with moderate disease, and 23 (96%) patients with severe disease. First degree atrioventricular block and left anterior hemiblock were the most commonly encountered abnormalities in patients with mild and moderate disease, whereas atrial fibrillation and flutter, abnormal Q waves, and repolarisation abnormalities were more common in patients with severe disease. This study shows that the heart is often affected by myotonic dystrophy. These effects can be detected by electrocardiography in early and mild forms of the disease. The effect on the heart is progressive and clinically important atrial arrhythmias and electrocardiographic abnormalities which are useful in differential diagnosis are common in severe forms of the disease.

Adolescent↗

PubMed1988

24-hour electrocardiographic study in myotonic dystrophy.

Thirty-eight consecutive adult patients with myotonic dystrophy were included in a study with electrocardiography at rest and 24-hour ambulatory electrocardiography. The patients were subdivided into three groups according to the severity of the disease. The prevalence of abnormal electrocardiograms at rest was 31, 50 and 100% in patients with mild, moderate and severe disease, respectively. The main characteristics observed at ambulatory electrocardiography were a high frequency of sinus bradycardia (58%) and intermittent atrioventricular block II (8%). These bradyarrhythmias were not correlated to the severity of the disease. Sustained atrial fibrillation or flutter was found in 3 patients (8%), all with the most severe form of the disease. Ambulatory electrocardiography should be used deliberately in the evaluation of patients with myotonic dystrophy and symptoms compatible with cardiac arrhythmias.

Adolescent↗