Abundances of ethylene oxide and acetaldehyde in hot molecular cloud cores

We have searched for millimetre-wave line emission from ethylene oxide (c-C2H4O) and its structural isomer acetaldehyde (CH3CHO) in 11 molecular clouds using SEST. Ethylene oxide and acetaldehyde were detected through multiple lines in the hot cores NGC 6334F, G327.3-0.6, G31.41+0.31, and G34.3+0.2. Acetaldehyde was also detected towards G10.47+0.03, G322.2+0.6, and Orion 3'N, and one ethylene oxide line was tentatively detected in G10.47+0.03. Column densities and rotational excitation temperatures were derived using a procedure which fits the observed line intensifies by finding the minimum chi 2-value. The resulting rotational excitation temperatures of ethylene oxide and acetaldehyde are in the range 16-38 K, indicating that these species are excited in the outer, cooler parts of the hot cores or that the excitation is significantly subthermal. For an assumed source size of 20", the deduced column densities are (0.6-1)x10(14) cm-2 for ethylene oxide and (2-5)x10(14) cm-2 for acetaldehyde. The fractional abundances with respect to H2 are X[c-C2H4O]=(2-6)xl0(-10), and X[CH3CHO]=(0.8-3)x10(-9). The ratio X[CH3CHO]/X[c-C2H4O] varies between 2.6 (NGC 6334F) and 8.5 (G327.3-0.6). We also detected and analysed multiple transitions of CH3OH, CH3OCH3, C2H5OH, and HCOOH. The chemical, and possibly evolutionary, states of NGC 6334F, G327.3-0.6, G31.41+0.31, and G34.3+0.2 seem to be very similar.

Are clouds collapsing at the 2' north position of Sagittarius B2?

The 3 mm lines of HCO2+ and HNCO have been observed toward Sgr B2. Besides the well-known "principal cloud" and an extended envelope, we find another gas cloud 2' north of Sgr B2(M). This 2' north (2' N) cloud which may be located behind the principal cloud, has a total mass of approximately 10(5) Msolar and a diameter of approximately 7 pc. HCO2+ and HNCO exist mainly at 2' north, and their column densities are about 2.2 x 10(14) and 2.3 x 10(15) cm-2, respectively. The fractional abundances of these species relative to molecular hydrogen appear to be enhanced by at least a factor of 10 compared to the principal cloud. We have also identified redshifted and blueshifted high-velocity components which move toward the 2' N position with projected velocities of +/- 30 km s-1. These components are located symmetrically around 2' N, along the Galactic plane, and have diameters of about 4-5 pc and masses of approximately 1 x 10(4) Msolar. The flow energies are large enough to initiate new star formation in the 2' N region on the free-fall timescale of 10(5) yr. This large-scale collapsing motion may cause a strong shock in the 2' N cloud and result in the enhancement of HCO2+ and HNCO.

Immunochemical and functional characterization of an agonist-like monoclonal antibody against the M2 acetylcholine receptor

Monoclonal antibodies were raised against a peptide corresponding to the second extracellular loop of the M2 acetylcholine receptor. One of the monoclonal antibodies, B8E5, was selected for further characterization on the basis of its high yield, its isotype (IgG2a), its dissociation kinetics and its agonist-like activity. The epitope recognized by B8E5 corresponded to the N-terminal part of the second extracellular loop of the receptor (V-R-T-V-E-) as determined by competition immunoassays and epitope scanning. The KA of B8E5 for the target peptide was assessed by surface plasmon resonance (SPR) to be 6.5x10(7) M(-1) by equilibrium and 3.7x10(7) M(-1) by kinetic analysis. B8E5 recognized the M2 acetylcholine receptor on rat cardiac tissue. It only recognized the non-reduced receptor in immunoblots. The antibody had no effect on antagonist binding but decreased the affinity for the agonist carbachol. B8E5 decreased the beating frequency of neonatal rat cardiomyocytes. The effect was specific since it was blocked by the target peptide and the antagonist atropine. The EC50 of the antibody corresponded to the KA measured by surface plasmon resonance. The physiological effect of the antibody did not lead to desensitization. The Fab fragments had no physiological effect; subsequent addition of anti-mouse IgG however restored the physiological effect. These results confirm that the N-terminus of the second extracellular loop is a functional target for antibodies against the M2 acetylcholine receptor. They suggest that the functional epitope is only accessible in the non-reduced receptor. The antibodies act through a functional dimerization of the receptor.

Risk indicators for cerebrovascular complications after coronary artery bypass grafting

All patients from western Sweden were retrospectively studied in whom CABG was performed between June 1, 1988 and June 1, 1991 without simultaneous valve surgery. The aim was to detect clinical factors prior to and at the time of coronary artery bypass grafting (CABG) which were associated with the risk of neurological complications during the postoperative hospital stay. A neurological complication during the hospital stay was registered if a neurological consultation was made and if this consultation diagnosed a neurological deficit. In all, there were 2121 patients in the study, of whom 81 (3.8%) had a neurological complication. 23 of the latter (28%) died before discharge. Among preoperative factors the following appeared as significant independent predictors of a neurological complication: a history of cerebrovascular disease (p < 0.001), diabetes mellitus (p < 0.01), hypertension (p < 0.05), degree of urgency of the operation (p < 0.01), and age (p < 0.01). Among pre- and post-operative events the following predicted a neurological complication: intensive care unit treatment for more than two days (p < 0.001) and respirator required for more than 24 hours (p < 0.001).

Effects of beta blockade on sudden cardiac death during acute myocardial infarction and the postinfarction period

About half of all deaths after myocardial infarction (MI) are sudden cardiac deaths. Most of these are thought to be due to ventricular fibrillation (VF). A number of interventions and many different antiarrhythmic agents have been investigated, but so far only beta-blocker therapy has been found to produce significant reductions in the risk of sudden cardiac death after MI. Reductions in total mortality and sudden cardiac death were first reported in 1981 in 3 placebo-controlled studies, the Norwegian Timolol Study, the American Beta-Blocker Heart Attack Trial (BHAT), and the Göteborg Metoprolol Trial. A few years later, two very large trials, the Metoprolol in Acute Myocardial Infarction (MIAMI) study and the First International Study of Infarct Survival (ISIS-1), which included 6,000 and 16,000 patients, respectively, showed that beta-blocker therapy could reduce mortality within the first 2 weeks after onset of MI. Data from 24 postinfarction studies with long-term follow-up show an average 20% mortality reduction over 2 years. Pooled results of 28 short-term, randomized, placebo-controlled trials in which beta blockers were given intravenously shortly after onset of MI indicate an average 13% mortality reduction within 2 weeks. In the 16 studies in which the sudden cardiac death rate was reported, the beneficial effect of beta blockade was even more marked: a 34% average reduction of risk. Not all studies with beta blockers, however, have demonstrated a significant reduction in the incidence of sudden cardiac death. Such an effect has been clearly demonstrated only for the more lipophilic beta blockers (timolol, metoprolol, and propranolol). Two of these lipophilic beta blockers, metoprolol and propranolol, have also been shown to prevent VF after MI in clinical studies. Based on observations from animal experiments, it has been proposed that beta blockers with a high degree of lipophilicity penetrate the brain and thereby maintain high vagal tone during stress. A combination of direct anti-ischemic effects due to beta1 blockade and preservation of vagal tone appears to prevent VF in these animal models. Further clinical studies are needed to explore this hypothesis.

Effect of metoprolol on the prognosis for patients with suspected acute myocardial infarction and indirect signs of congestive heart failure (a subgroup analysis of the Göteborg Metoprolol Trial)

The aim of this study is to describe the impact of early treatment with metoprolol on prognosis during 1 year of follow-up in patients with suspected acute myocardial infarction (AMI) and indirect signs of congestive heart failure (CHF). Patients aged 40-74 years who presented within 48 hours of onset of symptoms raising suspicion of AMI were assessed for inclusion. All patients participated in the Göteborg Metoprolol Trial and had indirect indices of CHF according to various clinical criteria. As soon as possible after hospital admission, patients received either placebo or metoprolol (15 mg) divided into 3 intravenous injections, then oral treatment, 200 mg daily for 3 months. Thereafter, most patients in both treatment groups received metoprolol in an open manner. Among the 1,395 randomized patients, 262 (19%) had signs of mild-to-moderate CHF before randomization. Of these, 131 were randomized to metoprolol and 131 to placebo. During the first 3 months, mortality was 10% among patients randomized to metoprolol versus 19% among patients randomized to placebo (p = 0.036). The corresponding figures for the first year were 14% and 27%, respectively (p = 0.0099). Patients randomized to placebo who showed signs of CHF had a 1-year mortality rate of 28% compared with 10% among patients without such signs (p <0.001). The results suggest that early treatment with metoprolol markedly reduces mortality in patients having suspected AMI and signs of CHF.

Detection of interstellar ethylene oxide (c-C2H4O)

We report the identification of 10 transitions that support the detection of the small cyclic molecule ethylene oxide (c-C2H4O) in Sgr B2N. Although one of these transitions is severely blended, so that an accurate intensity and line width could not be determined, and two other lines are only marginally detected, we have done Gaussian fits to the remaining seven lines and have performed a rotation diagram analysis. Our results indicate a rotation temperature T(rot) = 18 K and a molecular column density N(c-C2H4O) = 3.3 x 10(14) cm-2, corresponding to a fractional abundance relative to molecular hydrogen of order 6 x 10(-11). This is a factor of more than 200 higher than the abundance for this molecule suggested by the "new standard" chemistry model of Lee, Bettens, & Herbst. This result suggests that grain chemistry might play an effective role in the production of c-C2H4O. No transitions of this molecule were detected in either Sgr B2M or Sgr B2NW.

The role of beta-blockers in left ventricular dysfunction and heart failure

It was first reported by our group in 1975 that heart failure due to idiopathic dilated cardiomyopathy (IDC) could be improved by long term treatment with a beta-blocker, starting at a low dose and continuing with a stepwise up-titration. Since then, many studies have been performed in patients with heart failure of various aetiologies and the beneficial effects of long term beta-blockade have been confirmed. About 3000 patients have been included in randomised studies in which beta-blockade, given for more than 2 months, mostly elicited significant improvements in functional class, exercise capacity, cardiac function, quality of life and/or morbidity. When started at a very low dose (one-tenth to one-twentieth of the doses generally used in angina or hypertension), the treatment is well tolerated in most patients. In these studies, various types of beta-blockers were used, including beta1-selective blockers and nonselective blockers with additional properties (vasodilator and antioxidative) such as metoprolol, bisoprolol, bucindolol and carvedilol. Several large studies have also reported benefits on mortality and morbidity. In the Metoprolol in Dilated Cardiomyopathy (MDC) trial, metoprolol treatment in patients with IDC resulted in a 34% reduction of the primary combined endpoint, total number of deaths and need for cardiac transplantation. In the Cardiac Insufficiency Bisoprolol Study (CIBIS), in patients with idiopathic as well as ischaemic cardiomyopathy, there was a nonsignificant 20% reduction in mortality. In the US carvedilol studies (n = 1094), also in patients with ischaemic and idiopathic cardiomyopathy, carvedilol reduced mortality by 65%, which was highly significant. A nonsignificant reduction in mortality was observed in the Australia-New Zealand (ANZ) Heart Failure Study with carvedilol. In all these studies there was a reduction in hospitalisations, with all drugs being generally well tolerated. It can thus be concluded that the beneficial effects of beta-blockers on cardiac function and morbidity have been documented in a large number of studies in selected groups of patients. The treatment has been accepted in some countries by the regulatory authorities. Larger, placebo-controlled studies are needed to convincingly demonstrate a reduction in total mortality as observed in the pooling of the 4 US carvedilol studies. Such studies are in progress for various beta-blockers, which may lead to acceptance of their routine clinical use in patients with congestive heart failure.

Anti-M2 muscarinic receptor antibodies inhibit beta-adrenoceptor-mediated inotropic response in rat myocardium

The modulation of the inotropic effect by affinity-purified antibodies against a synthetic peptide corresponding to the second extracellular loop of the human muscarinic M2 receptors was studied in adult rat ventricular myocardium. These anti-muscarinic M2 receptor antibodies shifted the dose-response relationship of the beta-adrenoceptor agonist isoproterenol to higher concentrations whereas preimmune rabbit immunoglobulin G (IgG) or antibodies against the N-terminus of the beta 1-adrenoceptor had no effect. This effect of anti-muscarinic M2 receptor antibodies was fully blocked after preincubation with the antigenic peptide. No significant change of maximal inotropic response to isoproterenol was observed in the presence of anti-muscarinic M2 receptor antibodies. The anti-muscarinic M2 receptor antibodies did apparently not hamper the access of the muscarinic receptor agonist carbachol. The muscarinic receptor antagonist atropine attenuated the effect of the anti-muscarinic M2 receptor antibodies. The present study demonstrates for the first time in intact adult ventricular myocardium a specific stimulatory muscarinic activity of antibodies raised against a part of the muscarinic M2 receptor protein.

The nicotine inhaler in smoking cessation

BACKGROUND

Nicotine replacement therapy has been shown to improve success rates in smoking cessation treatment. However, the available products cause adverse effects, which prevent some smokers from using them. A new method of delivering nicotine via inhaler supplies nicotine orally through inhalation from a plastic tube. This mode of delivering nicotine resembles smoking, as it includes handling and active inhalation.

OBJECTIVES

To assess the efficacy and safety of the nicotine inhaler as an aid in smoking cessation.

METHODS

A 1-year, randomized, double-blind, placebo-controlled study was conducted in a smoking cessation clinic. Two hundred forty-seven smokers who smoked at least 10 cigarettes per day and who had previously made a serious attempt to stop smoking using nicotine chewing gum were recruited through advertisements. Randomization to treatment or control conditions were made at the first group session, with 123 participants receiving nicotine inhalers and 124 receiving placebo inhalers. The inhalers were distributed at the second session and participants were allowed to use the inhalers for 6 months.

MAIN OUTCOME MEASURE

Biochemically verified continuous abstinence from smoking after 2 and 6 weeks and at 3, 6, and 12 months.

RESULTS

Significantly more participants who had used the nicotine inhalers were continuously abstinent compared with those who had used the placebo inhalers. The respective success rates after 12 months were 28% and 18% (P = .046). At 6 months, 20 participants (16%) in the nicotine group were still using the inhaler, compared with 4 (3%) in the control group (P < .001).

CONCLUSION

The nicotine inhaler was an effective smoking cessation aid that produced a few mild and transient adverse effects.

Heart rate variability after acute myocardial infarction in patients treated with atenolol and metoprolol

Heart rate variability (HRV) reflects autonomous activity that influences the heart. It has been shown that HRV is depressed during acute myocardial infarction (AMI) and that it recovers with time. Beta-blockers reduce mortality after AMI and changes in sympathico-vagal activity have been suggested to be of importance. Under certain animal experimental conditions, metoprolol has been reported to increase vagal tone more than atenolol, which could have clinical implications. The purpose of the present study was to compare the effects of atenolol and metoprolol treatments on HRV during 6 weeks after AMI and to follow the post MI changes in HRV in patients on betablockers.

METHODS

In an open, randomised cross-over study, 28 patients were randomised to 3+3 weeks' treatment with atenolol or metoprolol starting 2-5 days after AMI. Twenty-four hour Holter recordings were made before randomisation and after 3 and 6 weeks. HRV was analysed as HR, SDRR, SDANN, SD, rMSSD and pNN50 in the time domain and as coefficient of component variance (CCV) of HF and LF, and as LF/HF ratio in the frequency domain.

RESULTS

The average daily dose in our study population was 106 mg of metoprolol and 54 mg of atenolol. There were trends toward lower heart rates daytime, lower LF/HF ratio daytime and higher rMSSD on atenolol compared to metoprolol. In the total group of 28 patients we found during the first 3 weeks, a significant increase of SDNN, SDANN (p<0.0001) and LF/HF ratio daytime and CCV-HF night-time (p<0.01). All differences and trends were unchanged between 3 and 6 weeks.

CONCLUSIONS

There was no evidence of more increased vagal tone with metoprolol compared to atenolol as has been suggested from animal models. In patients also on chronic treatment with beta blockers, an increase of HRV was seen during the first weeks post MI.

Growth hormone improves cardiac function in rats with experimental myocardial infarction

Accumulating evidence suggests from experimental and clinical studies beneficial effects of growth hormone (GH) on contractility, although concomitant cardiac hypertrophy, generally considered to be a cardiovascular risk factor, has also been reported. In the present study, we combine a rat model with impaired cardiac performance after myocardial infarction (MI) with echocardiographic evaluation of GH effects on cardiac structure and function. We have used a rat model with ligation of the left coronary artery in normal, growing male rats resulting in subsequent impaired cardiac performance. After 6 weeks' recovery, blind transthoracic echocardiography was performed to determine infarction size, cardiac geometry and performance. Rats with no signs of myocardial infarction were excluded from the study. After randomization, the rats were treated with daily s.c. injections of saline (n = 8) or recombinant human growth hormone (rhGH) (n = 6) at a dose of approximately 1 mg kg-1 body weight for 1 week. A new blind echocardiography examination was performed after treatment demonstrating a 13% increase in ejection fraction (EF) and a 50% increase in cardiac index in GH-treated rats compared with control rats (P < 0.01). Moreover, GH caused a significant decrease in end-systolic volume. There were no significant changes in left ventricular (LV) or interventricular wall thickness, LV dimensions, heart rate or diastolic function. No effects were seen on LV weight, cardiac insulin-like growth factor (IGF) I, IGF-I receptor and GH receptor mRNA content. GH in a physiological dose improves systolic function in an experimental model of heart failure without signs of hypertrophy, suggesting a potential role as a therapeutic agent in the treatment of heart failure and merits further investigation.

Predictors of hospital readmission two years after coronary artery bypass grafting

OBJECTIVE

To determine the clinical factors before, and in association with, coronary artery bypass grafting (CABG) that increase the risk of readmission to hospital in the first two years after surgery.

PATIENTS

All patients in western Sweden who had CABG without simultaneous valve surgery between 1 June 1988 and 1 June 1991.

METHODS

All patients who were readmitted to hospital were evaluated by postal inquiry and hospital records.

RESULTS

A total of 2121 patients were operated on, of whom 2037 were discharged from hospital. Information regarding readmission was missing in four patients, leaving 2033 patients; 44% were readmitted to hospital. The most common reasons for readmission were angina pectoris and congestive heart failure. There were 12 independent significant predictors for readmission: clinical history (a previous history of either congestive heart failure or myocardial infarction, or CABG); acute operation; postoperative complications (time in intensive care unit greater than two days, neurological complications); clinical findings four to seven days after the operation (arrhythmia, systolic murmur equivalent to mitral regurgitation); medication four to seven days after the operation (antidiabetics, diuretics for heart failure, other antiarrhythmics (other than beta blockers, calcium antagonists, and digitalis), and lack of treatment with aspirin).

CONCLUSION

44% of patients were readmitted to hospital two years after CABG. The most common reasons for readmission were angina pectoris and congestive heart failure. Four clinical markers predicted readmission: clinical history; acute operation status; postoperative complications; and clinical findings and medication four to seven days after operation.

Peptides derived from cardiovascular G-protein-coupled receptors induce morphological cardiomyopathic changes in immunized rabbits

An experimental model of early-stage cardiomyopathy was created by immunizing rabbits for 1 year with synthetic peptides corresponding to the sequence of the second extracellular loop of either beta-adrenoceptors or M2-muscarinic receptors. Thirty male rabbits were used and divided into three groups: a control group (n = 10), a group immunized with the peptide corresponding to the beta-adrenoceptor (beta 1 group) (n = 10) and a group immunized with the peptide corresponding to the M2-muscarinic receptor (M2 group) (n = 10). If the sera from both groups of immunized rabbits high-titres of anti-peptide antibodies were found throughout the study period but not in the sera from control rabbits or in the preimmune sera of immunized rabbits. No significant cross-reaction with peptides other than those used for immunization was found. The myocardial receptor density of both immunized groups displayed a strong trend toward receptor up-regulation. This was significant in the beta 1 group but not in the M2 group. Both groups of immunized rabbits displayed significantly enlarged ventricles and thinner walls, as compared with the control group. However, in contrast to the beta 1 group, which showed enlarged cavities in both left and right ventricles, the M2 group was mainly affected in the right ventricles. Moreover, morphological examinations of the hearts of rabbits from both immunized groups demonstrated focal myofibrillar lysis, loss of myofilament, mitochondrial swelling and condensation, sarcoplasmic vacuolation, deposition of dense granules in the sarcoplasm and the myofibrils. One of the sex control rabbit hearts which were examined showed mild degenerative changes in the myocardium and scant mononuclear cell infiltration. However, when all the control rabbit hearts were examined by electron microscopy, no significant alterations were found. These results suggest that immunization by peptides, corresponding to the target sequences for anti-receptor autoantibodies in idiopathic dilated cardiomyopathy, induces morphological changes in the heart similar to those found in the human disease.

Improvement of ED prediction of cardiac mortality among patients with symptoms suggestive of acute myocardial infarction

A study was undertaken to evaluate the 1-year risk of cardiac death for patients with chest pain/suspected acute myocardial infarction in the emergency department (ED) and express the prognosis in a statistical model. Clinical variables and electrocardiogram were correlated to cardiac death during 1 year. Cox regression model was used to estimate the risk of death as a continuous function of a risk score and the time interval. From these, the prognosis for each patient can be calculated. There were 6,794 visits by 5,303 patients followed for 1 year, during which 604 patients died. The absolute risk of cardiac death can be calculated from the independent predictors for cardiac death: age; sex; histories of diabetes mellitus, hypertension, and congestive heart failure; and symptoms, electrocardiographic pattern, and degree of suspicion of acute myocardial infarction on admission. This model allows estimation of the prognosis for every patient with chest pain/suspected acute myocardial infarction from data easily available in the ED.

Complications prior to revascularization among patients waiting for coronary artery bypass grafting and percutaneous transluminal coronary angioplasty

AIM

To describe the occurrence of death, development of acute myocardial infarction and need for hospitalization among patients on the waiting list for coronary artery bypass grafting and percutaneous transluminal coronary angioplasty.

PATIENTS AND METHODS

All the patients on the waiting list for possible coronary revascularization in September 1990 in western Sweden.

RESULTS

Of 718 patients waiting for either coronary artery bypass grafting or percutaneous transluminal coronary angioplasty, 15 (2.1%) died between the actual week in September 1990 and prior to revascularization and 12 (1.7%) developed a non-fatal acute myocardial infarction during the same period. All 15 patients who died before undergoing revascularization died a cardiac death. Death and/or the development of an acute myocardial infarction was significantly more frequent among the elderly, among patients with a low ejection fraction and among patients with a history of diabetes mellitus. In all, 29% required hospitalization prior to the procedure. The most common reason was symptoms of angina pectoris requiring hospitalization in 23% of the patients.

CONCLUSION

Among patients on the waiting list before either coronary artery bypass grafting or percutaneous transluminal coronary angioplasty, 15 (2.1%) died prior to the procedure and 1.7% developed a non-fatal acute myocardial infarction. The risk of either death or developing an acute myocardial infarction was highest among patients in the older age groups, among patients with a history of diabetes mellitus and among patients with a lower ejection fraction.

Cardiovascular and psychosomatic symptoms among relatives of patients waiting for possible coronary revascularization

OBJECTIVE

To examine the consequences for close family members of patients on a waiting list for possible coronary revascularization.

BACKGROUND

An increasing number of patients with symptomatic ischemic heart disease require evaluation for possible revascularization. Many of these patients must wait a long time before receiving treatment. The negative consequences of this long wait for patients and their relatives have not been satisfactorily evaluated previously.

DESIGN

Cross-sectional descriptive study.

SETTING

All hospital in Southwestern Sweden.

STUDY POPULATION

One hundred relatives of patients referred for possible revascularization and a sex- and age-matched reference group. The convenience sample consisted of 85% (n = 76) women and 15% (n = 13) men.

OUTCOME MEASURES

Frequency of cardiovascular and psychosomatic symptoms.

EVALUATION

One hundred relatives and 100 members of the control group were sent a questionnaire to evaluate their clinical condition; working situation; use of tobacco, alcohol and sedatives; and cardiovascular and psychosomatic symptoms.

RESULTS

Family members had a significantly higher frequency of anxiety, depression, and irritability compared with the control group. Furthermore, family members reported sleeping disorders, including difficulty waking, tiredness due to lack of sleep, and restless sleep, more frequently than did the control group.

CONCLUSION

Close family members of patients waiting for coronary revascularization have particular difficulties, and these difficulties should receive more attention.

Death, mode of death, morbidity and requirement for rehospitalization during 2 years after coronary artery bypass grafting in relation to preoperative ejection fraction

OBJECTIVE

To describe the impact of ejection fraction on the prognosis during 2 years after coronary artery bypass grafting (CABG).

PATIENTS

All patients in western Sweden who underwent CABG without concomitant valve surgery between June 1988 and June 1991.

RESULTS

In all, 2121 patients were operated upon and information on ejection fraction was available for 1961 patients (92%). Of these patients, 178 (9%) had an ejection fraction < 40%, 517 (26%) an ejection fraction of 40-59% and 1266 (65%) an ejection fraction > or = 60%. In these groups the mortalities during the first 30 days after CABG were 5.1, 4.3 and 2.2%, respectively (P < 0.01). The corresponding values for mortalities between 30 days and 2 years were 7.7, 4.3 and 3.3%, respectively (P < 0.01). Patients with a lower ejection fraction were more frequently men and more frequently had a history of cardiovascular disease. In multivariate analysis the preoperative ejection fraction was an independent predictor for total 2-year mortality. Patients with a low ejection fraction died more frequently in association with ventricular fibrillation. Morbidity was, with the exception of that for rehospitalization due to heart failure and infection, not associated significantly with the preoperative ejection fraction.

CONCLUSION

During the 2 years after CABG a low preoperative ejection fraction was associated with a higher mortality, but the association with morbidity was more complex.

Effects of anti-peptide antibodies against the second extracellular loop of human M2 muscarinic acetylcholine receptors on transmembrane potentials and currents in guinea pig ventricular myocytes

The effects of anti-peptide antibodies against the second extracellular loop of human M2 muscarinic receptor on transmembrane potentials and currents in guinea pig single ventricular cells were analyzed using whole-cell patch clamp technique. These effects were compared with those of the muscarinic receptor agonists carbachol and acetylcholine. The antibodies shortened the action potential duration in a dose-dependent manner. By using a ramp or step rectangular pulse protocol, it was found that the antibodies increased the outward K+ current and decreased the inward basal ICa significantly. The reversal potential of both carbachol- and antibody-induced extra currents were close to -80 mV, being in proximity to the calculated Ek of -90 mV. A beta-adrenergic receptor agonist, isoprenaline, prolonged the action potential and increased the overshoot which could be inhibited by both antibody and carbachol. Isoprenaline increased inward ICa and outward Ik simultaneously. Both antibody and carbachol could significantly reduce the isoprenaline-stimulated ICa but not the isoprenaline-stimulated Ik. The antibody- or carbachol-induced outward K+ current and the depressant effects of antibody and carbachol on isoprenaline-stimulated ICa were partially antagonized by atropine. These results suggest that the anti-M2 muscarinic receptor antibodies display a stimulatory activity similar to muscarinic receptor agonist on the receptor-mediated electrophysiological events.

Female sex is associated with increased mortality and morbidity early, but not late, after coronary artery bypass grafting

OBJECTIVE

To describe mortality and morbidity during a period of 2 years after coronary artery bypass grafting in relation to gender.

DESIGN

Prospective follow-up study.

SETTING

Two regional cardiothoracic centres which performed all the coronary artery bypass operations in western Sweden at the time.

SUBJECTS

A total of 2129 (1727 (81%) men and 402 (19%) women) consecutive patients undergoing coronary artery bypass surgery between June 1988 and June 1991 without concomitant procedures.

RESULTS

Females were older and more frequently had a history of hypertension, diabetes mellitus, congestive heart failure, renal dysfunction and obesity. In a multivariate analysis, taking account of age, history of cardiovascular diseases and renal dysfunction, female sex appeared as a significant independent predictor of mortality during the 30 days after coronary artery bypass grafting (P < 0.05), but not thereafter. Various postoperative complications including neurological deficit, hydro- and pneumo-thorax, perioperative myocardial damage and the need for assist devices and prolonged reperfusion were more common in females than males.

CONCLUSION

Females run an increased risk of early death and the development of postoperative complications after coronary artery bypass surgery as compared with males. Late mortality does not appear to be influenced by gender and the long-term benefit of the coronary artery bypass graft operation is similar in men and women.

Changes in early and late diastolic filling patterns induced by long-term adrenergic beta-blockade in patients with idiopathic dilated cardiomyopathy

BACKGROUND

beta-Blockers have been used in patients with idiopathic dilated cardiomyopathy to improve cardiac performance and theoretically would be beneficial to diastolic function. However, there are few reports on changes in diastolic function during chronic pharmacological treatment of congestive heart failure.

METHODS AND RESULTS

The present study was a substudy in the international Metoprolol in Dilated Cardiomyopathy Trial. Transmitral Doppler echocardiography was used to evaluate diastolic function in 77 patients randomly assigned to placebo (n = 37) or metoprolol (n = 40). The patients were treated for 12 months. Changes in Doppler flow variables in the metoprolol group implied a less restrictive filling pattern, expressed as an increase in E-wave deceleration time (placebo, 185 +/- 126 to 181 +/- 64 ms; metoprolol, 152 +/- 63 to 216 +/- 78 ms; P = .01, placebo versus metoprolol). Maximal increase in deceleration time had occurred by 3 months, whereas systolic recovery was achieved gradually and maximal effect was seen by 12 months of treatment. Although deceleration time was correlated to heart rate at baseline, changes in deceleration time were not significantly correlated to changes in heart rate during treatment.

CONCLUSIONS

During the first 3 months of treatment, maximal effects on diastolic variables were reached, whereas the most prominent effect on systolic function was seen late in the study. It is suggested that effects on diastolic filling account for subsequent later myocardial systolic recovery. The E-wave deceleration time, which in recent studies has been shown to be a powerful predictor of survival, was significantly improved in the metoprolol-treated patients.

Beta 1-adrenoceptor autoimmunity in cardiomyopathy

A growing body of studies have confirmed that autoantibodies against beta 1-adrenoceptors are present in different types of cardiomyopathy. This suggests that they play a role in the pathophysiology of the disease. This article will review the data indicating the presence of anti-beta 1-adrenoceptor autoantibodies in cardiomyopathy. It will focus upon their structural and functional properties which could explain their possible role in the induction and development of cardiomyopathic diseases.

Mortality and morbidity during a period of 2 years after coronary artery bypass surgery in patients with and without a history of hypertension

OBJECTIVE

To describe mortality and morbidity during a period of 2 years after coronary artery bypass grafting (CABG) in relation to a history of hypertension.

PATIENTS

All patients in western Sweden in whom CABG was undertaken between June 1988 and June 1991 and in whom simultaneous valve surgery was not performed were included in the study.

DESIGN

A prospective 2-year follow-up study.

RESULTS

Patients with a history of hypertension (n = 777) differed from patients without such a history (n = 1348) in that the proportion of women was higher, they were older and more frequently had a history of congestive heart failure, diabetes mellitus, renal dysfunction, cerebro-vascular disease, intermittent claudication and obesity, and the number of smokers and patients with previous CABG was lower. They were also more likely to develop post-operative cerebrovascular complications and signs of myocardia damage. Patients with hypertension tended to have increased mortality during the first 30 days after CABG and the late mortality (between day 30 and 2 years) was significantly higher than in non-hypertensive participants. Whereas the development of myocardial infarction was similar in both groups, the hypertensive study participants more frequently developed stroke during 2 years of follow-up. In a multivariate analysis including age, sex, history of different cardiovascular diseases, smoking, ejection fraction, and the occurrence of three-vessel disease, hypertension did not emerge as an independent predictor of death in the early or late phase or during a total of 2 years of follow-up.

CONCLUSION

Among CABG patients, those with a history of hypertension have a different pattern of risk factors. They have a higher mean age, include a higher proportion of women and have a higher prevalence of congestive heart failure, diabetes mellitus, renal dysfunction, cerebro-vascular disease, intermittent claudication, and obesity. They also have an increased frequency of immediate post-operative complications and an increased 2-year mortality, even if a history of hypertension was not an independent predictor of death during 2 years of follow-up.