Conjugation to antifibrin Fab' enhances fibrinolytic potency of single-chain urokinase plasminogen activator

Single-chain urokinase plasminogen activator (scu-PA) that had been modified with N-succinimidyl-3-(2-pyridyldithio)propionate was covalently linked by disulfide bonds to the Fab' of a monoclonal antibody specific for the beta-chain of fibrin (antibody 59D8). scu-PA-59D8 Fab' conjugate was separated from free scu-PA and two-chain urokinase coupled to 59D8 Fab' by two-step affinity chromatography. First, the reaction mixture was chromatographed on a column containing Sepharose linked to the peptide that had been used as immunogen for antibody 59D8; scu-PA-59D8 Fab' conjugate and unconjugated 59D8 Fab' were retained but not unconjugated scu-PA. Then, the eluate from the peptide-Sepharose column was chromatographed on a column containing Sepharose linked to benzamidine, which acts as a ligand for two-chain urokinase. The molecular weight of the scu-PA-59D8 Fab' conjugate was approximately 100 kDa when electrophoresed on a nonreducing sodium dodecylsulfate-polyacrylamide gel. Enzymatic assay after purification revealed that more than 97% of the scu-PA present in the conjugate retained the single-chain form. The Fab' portion of the conjugate functioned in a manner indistinguishable from that of native antibody 59D8. In an in vitro assay for lysis of fibrin monomer, the fibrinolytic potency of scu-PA-59D8 Fab' was 33-fold more than that of tissue plasminogen activator (p less than 0.001), 230-fold more than that of unconjugated scu-PA (p less than 0.0001), and 420-fold more than that of urokinase (p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic value of ambulatory Holter monitoring for the detection of coronary artery disease in patients with variable threshold angina pectoris

Patients with chronic stable angina pectoris may present with either fixed or variable threshold symptoms. To evaluate the diagnostic value of ambulatory Holter monitoring for the detection of coronary artery disease (CAD) in patients with variable threshold angina, 216 consecutive candidates for coronary angiography were investigated prospectively. For comparison, a group of 55 consecutive patients with fixed threshold angina was studied under the same conditions. Patients with prior myocardial infarction or angiographically documented CAD were excluded. Within 4 months of Holter monitoring, the advised coronary angiography was performed in 77% of the patients with variable threshold angina and in 89% of the patients with fixed threshold angina (p less than 0.05). The prevalence of CAD was markedly lower in patients with variable threshold angina compared to patients with fixed threshold angina (54 vs 90%, p less than 0.001). CAD patients of both subgroups, however, did not differ significantly with respect to the number of obstructed vessels, the Gensini coronary score, the number with impaired left ventricular function (ejection fraction less than 50%) or the duration of ischemic episodes during Holter monitoring. Diagnostic accuracy of Holter monitoring did not differ between variable and fixed threshold angina groups (67 vs 78%). In 91% of the patients results obtained by Holter monitoring could be compared to the results of a bicycle stress test. In patients with fixed threshold angina the diagnostic accuracy was similar for both tests (80 vs 80%). In patients with variable threshold angina, the diagnostic accuracy of Holter monitoring exceeded that of the exercise stress test (68 vs 55%, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Haemodynamic changes caused by alteration of autonomic activity in patients with heart failure

In 14 patients with heart failure (New York Heart Association class 2-3) and sinus rhythm the carotid sinus baroreceptors were stimulated to induce a reflex mediated decrease of sympathetic efferent activity and a simultaneous increase in vagal tone. Five patients were in severe heart failure (New York Heart Association class 3) with raised plasma concentrations of noradrenaline at rest (2.99 (0.86) nmol/l (mean (SD)) and nine patients had less severe heart failure (class 2.2 (0.2)) and normal plasma concentrations of noradrenaline at rest. The haemodynamic responses during arterial baroreceptor stimulation were different in both groups. In all five patients with severe heart failure cardiac output increased whereas in the nine patients with less severe heart failure it was unchanged or decreased. The increase of cardiac output in the group with severe heart failure was solely the result of a significant increase of stroke volume index (by 9 (2) ml/m2). In the nine patients with less severe heart failure stroke volume remained unchanged but heart rate decreased significantly by 7 (2) beats/min during baroreceptor stimulation. These data show that an integrated change of autonomic activity consisting of a decrease in sympathetic tone and an increase in vagal activity leads to an increase of stroke volume in patients with severe heart failure and hence to haemodynamic improvement.

Intravenous carbochromen: a potent and effective drug for estimation of coronary dilatory capacity

Systemic and coronary haemodynamic effects of carbochromen (0.125 mg kg-1 min-1 for 40 min i.v.) and dipyridamole (0.05 mg kg-1 min-1 for 10 min i.v.) were investigated in 18 patients without detectable heart disease. Both drugs induced a comparable increase in coronary blood flow (carbochromen: from 82 +/- 23 to 337 +/- 68 ml.100 g-1.min-1; dipyridamole: from 78 +/- 9 to 301 +/- 61 ml.100 g-1.min-1). This resulted in a minimal coronary resistance of 0.23 +/- 0.04 mmHg.ml-1.100 g.min for dipyridamole and of 0.24 +/- 0.04 mmHg.ml-1.100 g.min for carbochromen. In response to dipyridamole (n = 12) heart rate increased from 73 to 94 beats min-1 (P less than 0.005) and mean aortic pressure fell from 89 to 78 mmHg (P less than 0.001). After administration of carbochromen (n = 6) no significant systemic effects occurred. Dipyridamole induced a significant increase in myocardial oxygen consumption by 46% (P less than 0.001); after application of carbochromen myocardial oxygen consumption remained unchanged. From these data it can be concluded that for the evaluation of coronary dilatory capacity carbochromen may be more suitable than dipyridamole because (1) maximal coronary vasodilation is induced without changes in myocardial oxygen consumption and (2) no systemic effects occur.

Silent myocardial ischemia as a potential link between lack of premonitoring symptoms and increased risk of cardiac arrest during physical stress

The risk of cardiac arrest is increased during strenuous physical exercise in patients with stable coronary artery disease (CAD). Because premonitoring symptoms are rarely observed, silent myocardial ischemia may represent the pathophysiological basis for the induction of malignant ventricular arrhythmias. Holter monitoring was, therefore, performed in 40 consecutive patients entering a randomized intervention trial on progression of CAD. In 20 of 21 participants (95%) in the intervention program greater than or equal to 1 episode of silent myocardial ischemia was observed during the initial training session. The mean duration of silent myocardial ischemia per patient was 25 +/- 13 min/hr of training session. During normal daily activity only 5 patients (24%) experienced greater than or equal to 1 episode of silent myocardial ischemia (p less than 0.001) yielding a mean duration of 0.6 +/- 1.3 minutes of silent myocardial ischemia/hr of ordinary activity per patient (p less than 0.001 vs training session). During a control period of 24 hours without exercise training the incidence (33%) and mean duration of silent myocardial ischemia (0.8 +/- 2.1 min/hr/patient) were similar to those during normal daily activity on the day of the training session. During the training session the occurrence of frequent or repetitive ventricular arrhythmias was related to 10 silent myocardial ischemia episodes detected in 5 patients. During normal daily activity in 1 patient only was the onset of malignant ventricular arrhythmias associated with silent myocardial ischemia (p less than 0.05). Conditions and results of the Holter studies in the control group patients were comparable to those of the patients in the intervention group on the day without physical exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous thrombolytic therapy with a combination of single-chain urokinase-type plasminogen activator and recombinant tissue-type plasminogen activator in acute myocardial infarction

The effects of simultaneous intravenous infusions of 12 mg recombinant tissue-type plasminogen activator (rt-PA) over 30 minutes and 48 mg single-chain urokinase-type plasminogen activator (scuPA) over 40 minutes were studied in 38 patients with acute myocardial infarction. Coronary arterial patency was assessed angiographically 60 minutes and 90 minutes after initiation of treatment. Patency was achieved in 19 of 31 patients (61.3%) (95% confidence limits, 42-78%) at 60 minutes and in 27 of 33 patients (81.8%) (95% confidence limits, 65-93%) at 90 minutes. Nonspecific plasminogen activation was monitored by measuring relevant plasma parameters. At 60 minutes and 120 minutes, the fibrinogen concentration decreased slightly to 82.8 +/- 24.3% and 91.2 +/- 17.4% of the preinfusion level, and the plasminogen concentration to 66.3 +/- 15.2% and 65.3 +/- 13.4%, respectively. A greater consumption of alpha 2-antiplasmin was observed, which decreased to 30.7 +/- 22.8% and 32.2 +/- 21.2% of the preinfusion level at 60 and 120 minutes, respectively. No bleeding necessitating transfusion was observed. Two patients (5.3%) died during hospitalization. The findings suggest that the combined intravenous infusion of rt-PA and scuPA at appropriate doses induces highly effective coronary thrombolysis equal to the best results obtained with either rt-PA or scuPA alone. This efficacy is coupled with high specificity. Thus, the data support the potential use of combinations of rt-PA and scuPA in place of monotherapy.

Plasma concentrations of atrial natriuretic peptide during physical exercise in patients with congestive heart failure

Plasma concentrations of atrial natriuretic peptide (ANP) were measured in 25 patients with organic heart disease during physical exercise (baseline and maximum workload) in order to investigate if the responsiveness of stimulated release of ANP is still preserved in patients with heart failure and chronically elevated cardiac filling pressures. Since plasma concentrations of ANP are known to be positively correlated with mean right atrial pressures (RAP), the patients were divided into two groups according to their resting RAP; group I; those with normal RAP (less than or equal to 5 mmHg; n = 11); group II; those with elevated RAP (greater than 5 mmHg; n = 14). Under baseline conditions RAP (3.2 +/- 0.4 mmHg vs. 8.8 +/- 0.7 mmHg; p less than 0.01), pulmonary artery diastolic pressure (PADP; 9.5 +/- 0.9 mmHg vs. 17.9 +/- 1.8 pg/ml; p less than 0.01), and plasma ANP levels (128 +/- 19 pg/ml vs. 204 +/- 60 pg/ml; p less than 0.06) were significantly lower in group I than in group II. Both at rest and during maximum workload, plasma ANP concentrations were closely related to RAP, PADP, and mean pulmonary artery pressures in both groups. During exercise in all patients, RAP and PADP significantly increased, as well as plasma ANP concentrations. Similar increments in plasma ANP concentrations were accompanied by greater changes in RAP in group II than in group I. However, identical changes in PADP lead to identical increments in plasma ANP concentrations in both groups. In conclusion, the increments of plasma ANP concentrations during physical exercise were independent of the resting values of PADP, RAP, and plasma ANP concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

[Validation of trend-supported ST segment analysis of long-term ECG recordings]

Trend recordings of relative ST-segment deviations represent a useful tool for the identification of ischemia-like episodes during Holter monitoring. For the generation of trend recordings beat-to-beat data are filtered. The influence of the time constant of the filter on the sensitivity and the specificity for the detection of ischemia-like ECG changes is unknown, however. Ischemia-like episodes were, therefore, simulated and recorded by a frequency modulated Holter recorder and by a conventional six-channel ECG system. Relative ST-segment deviations were filtered using a time constant of 8, 16, 32 or 64 s, or an arithmetic averaging over 9 s for the generation of ST-segment trends. The magnitude of short-lasting ST-segment deviations was underestimated, when beat-to-beat data were filtered using time constants of greater than or equal to 32 s. The influence of posture-related ECG changes on the ST-segment trends was investigated by recording lead CM5 in 14 consecutive patients in different positions by a conventional ECG system. Four out of the 14 patients developed ST-segment elevations greater than or equal to 0.1 mV during leftsided position. Only in these four patients were ST-segment deviations of similar magnitude recorded during the following Holter monitoring. The posture-related ST-segment changes were characterized by an abrupt onset and an abrupt end, resulting in a box-like shape which enabled their correct identification in the ST-segment trend analysis. In order to determine the relative frequency of posture-related ST-segment changes, 35 patients with coronary artery disease (CAD) and 35 patients without underwent Holter monitoring.(ABSTRACT TRUNCATED AT 250 WORDS)

Independent sensitization of beta-adrenoceptors and adenylate cyclase in acute myocardial ischaemia

1. Acute myocardial ischaemia provokes sensitization of the adenylate cyclase system. This sensitization could be differentiated in a receptor-linked and an enzyme-linked sensitization. The increase in the number of beta-adrenoceptors in the plasma membranes was observed already after 15 min of global ischaemia (50 +/- 2 to 67 +/- 6 fmol mg-1 protein) and persisted after 50 min of ischaemia. The maximally isoprenaline-stimulated adenylate cyclase activity rose from 66 +/- 7 to 100 +/- 10 pmol cAMP min-1 mg-1 protein after 15 min of global ischaemia indicating the receptor-mediated sensitization of the beta-adrenergic system. However, after 50 min of ischaemia the isoprenaline-stimulated adenylate cyclase was reduced by about 50% despite the continuous increase of beta-adrenoceptors in the plasma membranes. 2. Additionally direct stimulation of the adenylate cyclase by forskolin revealed an increased enzyme activity after 15 min of global ischaemia (300 +/- 20 vs 378 +/- 25 pmol cAMP min-1 mg-1). Prolonged periods of ischaemia, however, caused a decline of the total adenylate cyclase activity (232 +/- 24 pmol cAMP min-1 mg-1 protein). This demonstrates an enzyme-specific sensitization of the adenylate cyclase, which in contrast to the rise in beta-adrenoceptors is only transient. This enzyme-specific sensitization or the late inactivation of the enzyme occur independently of receptor activation and cannot be prevented by beta-adrenoceptor blockade (10(-6) M alprenolol) prior to the ischaemic insult.(ABSTRACT TRUNCATED AT 250 WORDS)

Four-year follow-up study in patients with angina pectoris and normal coronary arteriograms ("syndrome X")

In patients with typical stress-induced anginal pain, normal coronary arteries, and unimpaired left ventricular performance at rest ("syndrome X"), a reduced coronary dilatory capacity, abnormal lactate metabolism during stress, and reduction of left ventricular functional reserve have been described. A group of 40 patients with syndrome X was followed for several years to determine their long-term prognosis. In 27 patients pulmonary artery pressure and in 19 patients left ventricular ejection fraction were reassessed during rest and exercise approximately 4 years after the initial examination. In patients with stress-induced ST-segment depression, these variables did not change during the observation period. In patients with constant or rate-dependent left bundle branch block, however, there was significant deterioration of left ventricular performance during rest (pulmonary artery mean pressure, 16 +/- 3 vs. 17 +/- 4 mm Hg, p = NS; left ventricular ejection fraction, 62 +/- 5% vs. 55 +/- 5%, p less than 0.05) and exercise (pulmonary artery, 30 +/- 6 vs. 39 +/- 10 mm Hg, p less than 0.005; left ventricular ejection fraction, 59 +/- 6% vs. 49 +/- 5%, p less than 0.01). These findings suggest that in syndrome X two subgroups with distinctly different prognoses may be defined: In patients with stress-induced ST-segment depression during exercise, left ventricular performance remains well preserved; however, in patients with either constant or rate-dependent left bundle branch block, there is significant deterioration of left ventricular function within several years.

Haemorrheological abnormalities in unstable angina pectoris: a relation independent of risk factor profile and angiographic severity

Plasma viscosity, photometric erythrocyte aggregation index, and erythrocyte filterability were measured in 194 patients with coronary artery disease. Patients with unstable angina (n = 64) had a higher plasma viscosity and photometric erythrocyte aggregation index than patients with stable angina (95% confidence intervals for the mean difference: 0.052-0.100 mPa.s for plasma viscosity, and 43%-72% for the photometric erythrocyte aggregation index). Multiple regression with fibrinogen, cholesterol, high density lipoprotein cholesterol, triglycerides, blood pressure, smoking habits, coronary artery score, and left ventricular ejection fraction as independent variables showed a significant partial correlation between fibrinogen and the photometric erythrocyte aggregation index (r2 = 0.20) and plasma viscosity (r2 = 0.09), between triglycerides and plasma viscosity (r2 = 0.05), and between aortic pressure and erythrocyte filterability (r2 = 0.03). Logistic regression for unstable/stable angina with the haemorrheological variables as independent variables correctly identified 72% of the patients with stable angina and 78% of those with unstable angina. Inclusion of all the variables investigated did not substantially improve the discriminative potential of the logistic regression model. Unstable angina is associated with an impairment of blood fluidity that is essentially independent of risk factor profile and angiographic data.

[Continuous ventricular tachyarrhythmia in patients without detectable organic heart disease: clinical and electrophysiologic findings]

In 22 of 335 consecutive patients (6.6%) referred for evaluation and treatment of sustained ventricular tachyarrhythmias, hemodynamic and angiographic findings revealed no structural heart disease. Entry arrhythmia was ventricular fibrillation in 10 patients and sustained ventricular tachycardia in 12 patients. A subgroup of four young patients presented with slow recurrent (during 51 +/- 43 months) sustained ventricular tachycardias that were reproducibly terminated by intravenous application of verapamil. Programmed ventricular stimulation replicated the clinical arrhythmia in nine patients (75%) with ventricular tachycardia. In five patients (50%) with ventricular fibrillation no sustained ventricular arrhythmia could be induced, and only with three extrastimuli in four of the remaining five patients. On hospital discharge, 14 patients received type III antiarrhythmic agents, five patients received type I agents, and one patient received verapamil. Two patients were discharged without medical therapy. During the following 24 +/- 9 months, four patients had recurrent sustained ventricular tachycardia. No patient died suddenly during follow-up. We conclude that about 6% of all patients with ventricular tachyarrhythmias have apparently normal hearts. These idiopathic tachyarrhythmias seem to have a benign course, at least when treated. Slow, verapamil-sensitive tachycardias of young people may represent a unique entity.

Enzyme linked immuno assay of cardiac troponin T for the detection of acute myocardial infarction in patients

For the diagnosis of acute myocardial infarction (AMI) in patients circulating constituents of the contractile apparatus may be measured instead of cytosolic cardiac enzymes. The potential advantages of the use of myofibrillar cardiac proteins as marker proteins for AMI results from their expression as cardio-specific isoforms, their high intracellular concentration, and their continuous release from infarcting myocardium. While analyzing the specificity of polyclonal goat anti-human cardiac myosin light chains antisera a cardio-specific antibody fraction was identified which is directed against cardiac troponin T contaminations of the myosin light chains antigen. Using this antibody fraction a standardized enzyme immuno-assay for circulating troponin T was developed to detect AMI in patients. In this assay troponin T is bound on different epitopes by affinity purified goat anti-cardiac troponin T antibodies immobilized on polyvinyl chloride test tubes as well as horse raddish peroxidase labeled monoclonal anti-troponin T antibody in liquid phase. The assay procedure can be completed semiautomatically in 90 min with a detection limit of the assay of 0.5 ng/ml human or bovine cardiac troponin T. There is 1% crossreactivity with skeletal troponin T. In 26 healthy volunteers no cardiac troponin T was detectable in serum of 25 persons, while in 1 further volunteer 1 ng/ml troponin T was found. In the sera of all 50 patients with transmural AMI troponin T was elevated ranging from 7.2 to 110 ng/ml. In the mean troponin T remained elevated from three until 300 hours after onset of ischemic pain showing a biphasic serum concentration curve.(ABSTRACT TRUNCATED AT 250 WORDS)

[Peracute constrictive, idiopathic pericarditis--a case report of an acute life-threatening disease picture]

Generally, idiopathic pericarditis is considered a benign, self-limiting disease. Frequently, the exsudative phase of the disease is followed by a mild form of transitory constriction of the pericardium. The case reported here shows an unusual course of the disease. Shortly after the symptoms of exsudative pericarditis subsided a life-threatening form of pericardial constriction developed within weeks. In case of chronic pericardial constriction perioperative mortality for partial pericardiectomy is not insignificant. This is a result of myocardial damage that is difficult to assess prior to surgery. For that reason a partial pericardiectomy should be attempted as early as possible, even in cases with acute pericardial constriction.

Plasma cholesterol, lipid lowering, and risk for cancer. An update of the results from epidemiologic studies and intervention trials

Plasma cholesterol has been shown to be correlated to the incidence of cardiovascular events. This observation and experimental data on the pathogenesis of atherosclerosis have led to a number of recommendations for the treatment of elevated plasma lipids by national and international consensus panels and organizations. However, the issue whether lowering cholesterol might increase the risk for other diseases including cancer is still controversial. In this article, an attempt is made to review the currently available data on the relation between plasma cholesterol and cancer. Special emphasis is given to the results of intervention trials aimed at lowering cholesterol by diet and/or drugs, because they apply best to the human situation and are particularly relevant for the clinician. Data from animal experiments are only briefly discussed.

[Diagnosis of cardiac causes of cerebral embolism: a contribution to 2D echocardiography and long-term ECG]

Certain cardiac diseases are regarded as potential sources of embolic strokes. Due to the high risk of recurrent brain embolism diagnosis of a potential cardiac source implies therapeutic consequences in most cases. The contribution of 2D-echocardiography and of ECG Holter monitoring to the detection of possible cardiac sources of cerebral embolism is not yet fully established. We therefore performed 2D-echocardiography and 24-h Holter monitoring in 135 consecutive patients with regional cerebral ischemia. In 17 (12.6%) out of the 135 patients a potential cardiac source of cerebral embolism was found, four of them presented with two cardiac disorders compatible with a cardiac source of embolism. In 10 patients a cardiac disease as potential source of cerebral embolism was already detected during routine examination. 2D-echocardiography disclosed no cardiac embolic source, which was not suspected before but confirmed the diagnosis in five cases. Holter monitoring identified 16 cases with arrhythmias, which may cause systemic embolism. Among these cases seven were not detected during the routine examinations, all of them suffered from intermittent atrial fibrillation. It is concluded that Holter monitoring contributes more than 2D-echocardiography to disclose hitherto unsuspected potential cardiogenic sources of brain embolism.

[Antibody mediated thrombolysis. A new therapeutic principle]

Thrombosis of a coronary artery is the most common cause of myocardial infarction. Thrombolytic therapy, when instituted timely, has been shown capable of reducing morbidity and mortality. However, the use of presently available thrombolytic agents is associated with a bleeding tendency and efficacy is not optimal. This article reviews one of several lines of investigation that are presently being pursued in order to improve efficacy and specificity of thrombolytic therapy. The chemical conjugation of a fibrin specific monoclonal antibody and urokinase or tissue plasminogen activator results in markedly enhanced thrombolytic potency, both in vitro and in vivo. Specificity of the conjugates is greater than that of the parent plasminogen activators as reflected by conservation of fibrinogen, plasminogen and alpha-2 antiplasmin. A bispecific antibody, with specificity for both, fibrin and tissue plasminogen activator, has the potential of concentrating endogenous tissue plasminogen activator at the site of a thrombus. In the presence of the bispecific antibody, efficacy and specificity of tissue plasminogen activator are markedly enhanced in vitro and in vivo. The tools of molecular biology are presently being applied in order to translate these findings into better thrombolytic therapy.

[Long-term results of pacemaker therapy in hypersensitive carotid sinus syndrome]

131 patients received permanent pacemakers to treat their hypersensitive carotis sinus syndrome (HCSS). Prior to implantation, HCSS was diagnosed whenever spontaneous episodes of faintness or dizziness (n = 25) or syncope (n = 106) coincided with an abnormal response to carotis sinus massage (asystole greater than 3 s). 123 patients were followed for 48 +/- 27 months after implantation to assess the value of pacemaker therapy. 77% of all patients were free of initial symptoms. 90% of patients with syncope prior to pacemaker therapy were free of recurrence. Therefore, permanent pacing appears to be the treatment of choice for these patients. Since carotis sinus massage produced high-degree AV-block in at least 33% of patients, ventricular (rather than exclusive atrial) pacing seems to be mandatory. However, syncope did recur in 10% despite normal pacemaker function. The etiology of these recurrences remained unclear in almost all patients. As opposed to patients with syncope, cardiac pacing prevented symptoms in only 26% of patients with faintness or dizziness without full syncope. In these patients primary and sole pacemaker therapy does not appear to be appropriate.

Haemorheologic studies in patients with reduced coronary vasodilator capacity but normal coronary angiogram (syndrome X)

The cause of syndrome X, i.e. typical angina, positive exercise test, normal coronary angiogram, normal resting cardiac function, but reduced coronary vasodilator capacity is still unknown. The purpose of the study was to investigate blood fluidity as a possible cause of syndrome X. Haematocrit, plasma viscosity, erythrocyte aggregation, and erythrocyte deformability were examined in 14 patients with syndrome X (group 1), 24 patients with typical angina, positive exercise test, but normal coronary vasodilator capacity (group 2), and 37 patients with atypical chest pain and normal coronary arteries (control group). Coronary vasodilator capacity was determined by the argon method. Compared with normals, patients with syndrome X showed an elevated plasma viscosity (1.31 +/- 0.05 mPas vs 1.26 +/- 0.04 mPas, 2P less than 0.01), an elevated erythrocyte photometric aggregation index (141 +/- 27% vs 100 +/- 23%, 2P less than 0.01) and a reduced erythrocyte filterability (0.51 +/- 0.12 vs 0.66 +/- 0.09, 2P less than 0.01). Significant differences in the haemorheologic parameters between group 1, group 2 and the control group, however, were not detected. Multiple regression analysis did not reveal a significant relationship between coronary vasodilator capacity and the haemorheologic parameters tested. The data suggest that the reduction in coronary vasodilator capacity in patients with syndrome X cannot be attributed to haemorheologic alterations.

Heart innervation after ligation of the left anterior descending coronary artery (LAD)

Distribution and amount of neuropeptide Y- and synaptophysin-immunoreactive nervous structures within the heart were investigated in dogs 4 days after ligation of the left anterior descending coronary artery (LAD). In the right atrium and posterior left ventricular regions, which were taken as (non-infarcted) control areas, neuropeptide Y-immunoreactive paravascular nerves and a perivascular nerve plexus running within the adventitia of the coronary arteries and their branches down to the arterioles were observed. Morphometric measurements of the area density revealed 0.099 +/- 0.014% for synaptophysin- and 0.037 +/- 0.0072% for neuropeptide Y-immunoreactivity within the posterior wall of the left ventricular myocardium. Four days after ligation of the LAD only single synaptophysin- and neuropeptide Y-immunoreactive nerve fibers were very rarely detected in the infarcted region of the anterior wall of the left ventricle. Above the ligature larger than normal neuropeptide Y-immunoreactive axons within nerves along the LAD indicated a blockage of the axoplasmic transport of this peptide. When investigating this model of experimental myocardial infarction, mechanical traumatization of peri- and paravascular nerves of the LAD by the ligature has to be considered as a major pathogenetic factor, in addition to ischemia leading to denervation of infarcted as well as non-ischemic myocardium.