Biomedical subjects

H Kreuzer

Publications and source records attributed to H Kreuzer.

At least 109 records · Page 6Linked to original sources

PubMed1993

Rapid preparation of subsarcolemmal and interfibrillar mitochondrial subpopulations from cardiac muscle.

1. Subsarcolemmal and interfibrillar mitochondria were prepared with complete recovery from rabbit and porcine heart muscle by upward-flotation during 60 sec of Percoll density gradient centrifugation. 2. Mitochondrial subpopulations were identified and characterized according to buoyant density, electron-microscopy, marker enzyme activities and respiratory performance. 3. ADP-induced state 3-respiration related to latent citrate synthase activity as a marker for structurally intact mitochondria was not significantly different in both mitochondrial subtypes.

Adenosine Diphosphate↗

PubMed1993

Aorto-coronary artery to coronary vein fistula with the potential of coronary steal as complication of saphenous vein jump bypass graft.

We report the first documented case of an iatrogenic aorto-coronary artery to coronary vein fistula secondary to an aortocoronary saphenous vein jump bypass graft inadvertently anastomosed to a coronary vein. Angiographic and oximetric results of left and right cardiac catheterization--including direct catheterization of the anastomosed coronary vein--as well as clinical data with a four-year follow-up are presented. The role of surgery, percutaneous transcatheter embolization, and conservative treatment is discussed in this unique case with the potential of a coronary steal phenomenon.

Anastomosis, Surgical↗

PubMed1993

Myocardial indium-111 antimyosin uptake in patients with idiopathic dilated cardiomyopathy: its relation to haemodynamics, histomorphometry, myocardial enteroviral infection, and clinical course.

The myocardial uptake of indium-111 antimyosin indicates the presence of ongoing myocyte damage. To evaluate the role of this finding in patients with idiopathic dilated cardiomyopathy (IDC), 36 patients were studied by planar and SPECT antimyosin imaging. The diagnosis of IDC was based on coronary angiography and left ventricular endomyocardial biopsy. The antimyosin scan was evaluated qualitatively from SPECT images and assessed quantitatively by a count density index (CDI) which measured the tracer activity over the heart relative to the lung and sternal region (normal value less than 1.20). Group 1 consisted of 13 patients (36%) with an increased myocardial antimyosin uptake, while 23 patients had a normal antimyosin scan (group 2). Clinical data, pulmonary artery pressures, gated blood pool ejection fraction and histomorphometry of endomyocardial biopsies were similar in both groups. During a follow-up of 21 +/- 12 months there were two cardiac deaths in group 1 and 10 deaths in group 2 (P = 0.12). The 2-year survival rate was 81% and 59%, respectively. During follow-up, there was no significant change in haemodynamic parameters in either group, but there was a slight improvement in functional NYHA class in group 1 (P < 0.05). No association was found between the presence of myocardial enterovirus infection, determined in 17 patients by in situ hybridization and the antimyosin scan (P = 0.5 g). Myocardial antimyosin uptake was found in a high percentage of patients with IDC, indicating ongoing myocyte damage. This finding was not related to any clinical, haemodynamic, morphological parameter, or enterovirus infection. Myocyte damage is a distinct feature in a subgroup of patients with IDC unrelated to any known causes of myocellular destruction. This subgroup showed a trend towards a more favourable clinical outcome.

Actuarial Analysis↗

PubMed1993

Validation of automated sleep stage and apnoea analysis in suspected obstructive sleep apnoea.

Full-night polysomnography is necessary for the diagnosis of obstructive sleep apnoea (OSA). However, analysis of the sleep stages and apnoeas is time-consuming. Computer systems for automated analysis have, thus, been developed to alleviate this task. We investigated 27 consecutive patients referred to our sleep laboratory with suspected OSA. The analysis of sleep stages and apnoeas was performed by visual scoring, according to Rechtschaffen and Kales, and by commercially available automated analysis device. The mean difference between visual scoring and automated analysis was -1, 111, -140, -3, 1 and 27 min, for sleep stages awake, I, II, III, IV and rapid eye movement (REM) respectively. For the apnoea index, the automated analysis rated a lower figure (mean difference 7.h-1, 95% confidence interval 2-12.h-1). The diagnosis of OSA was performed with a sensitivity of 85% and a specificity of 93% by automated analysis. Comparison of two independent handscores showed good agreement, with a mean difference of 6, 4, 3, -7, 1 and -1 min, for sleep stages awake, I, II, III, IV and REM, respectively. In conclusion, the automated analysis underestimates stage I sleep and the apnoea index. Visual scoring is advisable for control of the results. Automated analysis should only be used by those who are able to perform a visual analysis.

Aged↗

PubMed1993

[Ventricular macro-reentry tachycardia of the bundle branch type--indications for catheter ablation].

Out of 115 patients with recurrent sustained monomorphic ventricular tachycardia who underwent catheter ablation between August, 1987 and May, 1992, 7 were found to have bundle branch reentry. Bundle branch reentrant tachycardia was assumed if His potential or bundle branch potential preceded ventricular activation during tachycardia with identical H-H'- and V-V'-intervals. In 5 patients, catheter ablation of the right bundle branch and in 2 patients, ablation of the proximal left bundle branch were performed with direct current or radiofrequency energy. The procedure was successful in all 7 patients. During the follow-up of 15 +/- 12 months, 3 patients died due to cardiac failure. One patient had sustained ventricular tachycardia 12 months after catheter ablation which was not due to bundle branch reentry and was treated with an implantable cardioverter/defibrillator. Atrioventricular conduction delay in the surface electrogram and during electrophysiologic study may give a hint at bundle branch reentrant ventricular tachycardia since it was seen in 5 of our 7 patients. Catheter ablation of one bundle branch is an effective treatment which can prevent recurrence of this tachycardia.

Aged↗

PubMed1992

Frequency of complications of cardiopulmonary resuscitation after thrombolysis during acute myocardial infarction.

Prolonged external cardiac massage is often regarded as a contraindication for thrombolytic therapy because of the risk of fatal hemorrhage. The influence of cardiopulmonary resuscitation on complications of thrombolytic bleeding was assessed analyzing data of all patients with myocardial infarction admitted to our clinic during the 10-year period between 1978 and 1987. From the total of 2,147 patients with acute myocardial infarction, 590 received thrombolytic therapy (intracoronary in 229, intravenous in 400). Of these, 43 patients underwent prolonged cardiopulmonary resuscitation and received thrombolysis within a time interval of less than 24 hours. In 21 patients, resuscitation was performed within a short period of time (5 minutes to 20 hours) after thrombolysis (10 intracoronary, 10 intravenous, 1 intravenous + intracoronary) had been initiated; 9 of these patients survived (43%). In the other 22 patients, thrombolytic therapy was initiated during ongoing resuscitation (n = 6: intravenous in 5, intravenous + intracoronary in 1) or in the early phase (10 to 120 minutes) after successful resuscitation (n = 16: intracoronary in 10, intravenous in 4, intravenous + intracoronary in 2). From this group, 14 patients survived (in-hospital mortality 36%). The mean duration of cardiopulmonary resuscitation was 36 +/- 32 minutes (range 4 to 120). Autopsy studies were performed in 16 of 20 decreased patients. Bleeding complications occurred in 8 of 43 patients. No case of bleeding was directly related to cardiocompression despite the often traumatic procedure with rib fractures verified in 17 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Cholinesterases of heart muscle. Characterization of multiple enzymes using kinetics of irreversible organophosphorus inhibition.

Cholinesterases of porcine left ventricular heart muscle were characterized with respect to substrate specificity and inhibition kinetics with organophosphorus inhibitors N,N'-di-isopropyl-phosphorodiamidic fluoride (Mipafox), di-isopropylphosphorofluoridate (DFP), and diethyl p-nitro-phenyl phosphate (Paraoxon). Total myocardial choline ester hydrolysing activity (234 nmol/min/g wet wt with 1.5 mM acetylthiocholine, ASCh; 216 nmol/min/g with 30 mM butyrylthiocholine, BSCh) was irreversibly and covalently inhibited by a wide range of inhibitor concentrations and, using weighted least-squares non-linear curve fitting, residual activities as determined with four different substrates in each case were fitted to a sum of up to four exponential functions. Quality of curve fitting as assessed by the sum of squares reached its optimum on the basis of a three component model, thus, indicating the presence of three different enzymes taking part in choline ester hydrolysis. Final classification of heart muscle cholinesterases was obtained according to both substrate hydrolysis patterns with ASCh, BSCh, acetyl-beta-methylthiocholine and propionylthiocholine, and second-order rate constants for the reaction with organophosphorus inhibitors Mipafox, DFP, and Paraoxon. One choline ester-hydrolysing enzyme was identified as acetylcholinesterase (EC 3.1.1.7), and one as butyrylcholinesterase (EC 3.1.1.8). The third enzyme with relative resistance to organophosphorus inhibition was classified as atypical cholinesterase.

Acetylthiocholine↗

PubMed1992

[The percutaneous implantable heart-lung machine in the coronary angioplasty of high-risk and emergency patients].

Using a recently developed, percutaneously introduced cardiopulmonary support system (PCPS) seven high-risk patients (four men, three women; mean age 61 [41-77] years) underwent percutaneous transluminal coronary angioplasty. In one patient, with unstable angina and in incipient cardiogenic shock, perfusion with PCPS was begun immediately before coronary angioplasty. In six patients it was undertaken with the PCPS on stand-by, but eventually not needed. Coronary angioplasty was successful in six patients, partially successful in one. Angina was considerably improved long-term in all patients, but one of them died 2.5 months afterwards at home. In two other patients (men, aged 41 and 71 years) with acute myocardial infarction, the PCPS was employed under circumstances of emergency resuscitation. In both cases recanalization of the occluded coronary artery was achieved mechanically during perfusion with PCPS; one patient survived. Availability of PCPS, also in an emergency, makes it possible to extend the indications for coronary angioplasty to include even high-risk patients.

Adult↗

PubMed1992

Significance of coronary angiography, left heart catheterization, and endomyocardial biopsy for the diagnosis of idiopathic dilated cardiomyopathy.

Many physicians assume that a reliable diagnosis of idiopathic dilated cardiomyopathy can be made by noninvasive methods, mainly echocardiography. On the other hand, use of endomyocardial biopsy in those patients who have undergone left heart catheterization and who demonstrate left ventricular dysfunction of unknown origin is increasing. Therefore the purpose of this study was to investigate the yield of that diagnostic strategy in patients with the tentative diagnosis of idiopathic dilated cardiomyopathy. Between 1980 and 1988, 3.2% of our 15,442 patients were diagnosed as having idiopathic dilated cardiomyopathy on the basis of left heart catheterizations and coronary angiograms. Idiopathic dilated cardiomyopathy was diagnosed in 444 patients on the basis of clinical data and results of noninvasive tests before catheterization, but in only 295 of these cases was the diagnosis confirmed by means of coronary angiography and left heart catheterization (predictive value of noninvasive tests is 66%). The remaining 34% of patients demonstrated extensive coronary artery disease (13%), significant valvular heart disease (11%), and other or no heart disease (10%). The diagnostic sensitivity of noninvasive tools (patient history, ECG, stress test, echocardiography) was only 59%. Left heart catheterization can easily be combined with endomyocardial biopsy. With the use of histologic techniques, specific heart muscle diseases were detectable in 3.5% of 209 patients, but in only 1% could therapeutic consequences be determined. Thus coronary angiography and left heart catheterization are mandatory for the correct diagnosis of idiopathic dilated cardiomyopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗

PubMed1992

Restenosis after excimer laser angioplasty of coronary stenoses and chronic total occlusions.

In an open clinical study, a xenon-chloride excimer laser was used for angioplasty of coronary stenoses (n = 48) and chronic total occlusions (n = 56) in 104 patients. Multifiber catheters (4.0F to 5.5F) transmitted 37 to 120 mjoules/mm2 of fiber surface. Excimer laser angioplasty was successful in 43 patients with a stenosis (89%), followed by percutaneous transluminal coronary angioplasty in 21 patients (49%) to reduce the stenosis to less than 50% luminal narrowing. In 39 patients (70%) with a chronic occlusion (age 1 to 14 months), recanalization by means of excimer laser angioplasty was successful, with subsequent percutaneous transluminal coronary angioplasty performed in 23 patients. Major complications included one perforation, one acute occlusion, and two severe dissections. Six-month angiographic follow-up examinations after successful angioplasty were completed in 40 patients (98%) with stenoses and 34 (94%) with occlusions. Restenosis (greater than 20% decrease in luminal diameter) occurred in 13 patients (33%) with stenoses and in 16 patients (47%) after angioplasty of a chronic occlusion. These long-term results indicate that restenosis after excimer laser angioplasty of coronary stenoses and chronic total occlusions is similar to reported results of conventional balloon angioplasty.

Angioplasty, Balloon↗

PubMed1992

Protective effects of the Hemopump left ventricular assist device in experimental cardiogenic shock.

The efficacy of the new cable-driven rotating left ventricular assist device Hemopump in cardiogenic shock was examined in experiments with adult sheep (n = 14; body weight 50-71 kg). Shock was induced by high frequency ventricular pacing. Aortic, pulmonary, central venous and left ventricular pressures as well as electromagnetic measurements of coronary blood flow were recorded continuously; cardiac output was measured by thermodilution technique. Blood samples for determination of oxygen content, electrolytes and lactate were taken under control conditions, in shock, and during pump intervention at different levels of pump speed. Vascular resistance, total body and myocardial oxygen consumption as well as myocardial uptake and release of lactate were calculated. High frequency pacing led to a significant decrease in cardiac output (from 3.8 +/- 0.8 to 2.2 +/- 1.6 l/min), mean aortic pressure (89.1 +/- 14.4 to 47.6 +/- 7.2 mmHg), and total body oxygen consumption (2.6 +/- 0.3 to 1.4 +/- 0.7 ml/min per kg), as well as myocardial release of lactate (arterial coronary-venous difference of lactate: 0.27 +/- 0.26 to -0.32 +/- 0.72 mmol/l). Hemopump assist in this condition resulted in a significant increase in cardiac output (to 2.8 +/- 0.6 l/min), mean aortic pressure (to 65.6 +/- 13.9 mmHg), and myocardial perfusion pressure (from 25.5 +/- 11.0 to 59.0 +/- 14.7), and led to nearly normal total body oxygen consumption (2.5 +/- 0.7 ml/min per kg), a decrease in myocardial oxygen consumption (from 6.1 +/- 2.1 in shock, to 4.8 +/- 1.7 ml/min per 100 g), and to normal arterial coronary-venous difference of lactate (0.24 +/- 0.26 mmol/l).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Efficiency of the left ventricle assist device Hemopump in cardiac fibrillation.

We have examined in sheep the efficiency of the Hemopump during ventricular fibrillation. Circulatory arrest was induced by electrical stimulation and maintained for 30 min. Haemodynamic measurements were recorded continuously and blood samples were taken before, during and after fibrillation to determine total body and myocardial metabolic activity. All hearts were defibrillated successfully after 30 min of fibrillation. During fibrillation, the Hemopump sustained a mean arterial pressure of about 60 mm Hg with a blood flow rate of about 2.3 litre min-1. These perfusion conditions were sufficient for maintenance of aerobic myocardial metabolism, but with a borderline circulatory supply to the total organism.

Animals↗

PubMed1992

Budd-Chiari syndrome as the primary manifestation of a fibrolamellar hepatocellular carcinoma.

An 18-year-old female patient was admitted with ascites, right upper abdominal tenderness and peripheral edema. Angiography showed complete occlusion of the vena cava inferior up to the level of the right atrium. By open heart surgery, masses of thrombotic material were pulled out of the v. cava inferior/vv. iliacae which histologically contained tumor cell populations consistent with a hepatocellular carcinoma. Celiacography showed a highly vascularized tumor in the right hepatic lobe. Histologically, it proved to be fibrolamellar subtype hepatocellular carcinoma.

Adolescent↗

PubMed1992

Coronary angioplasty in patients with previous coronary artery bypass grafting.

Between 1982 and 1990, in 134 patients with prior coronary artery bypass grafting and recurrent angina, repeat coronary angiography and balloon angioplasty of stenoses in grafts or native arteries were attempted. Mean age of grafts was 45.6 months, range three days to twelve years. At the time of angioplasty, 6 patients had one-vessel-disease, 33 had two-vessel-disease, and 95 had three-vessel-disease. A total of 182 lesions were dilated: 55 venous grafts, 3 internal mammary artery grafts, and 124 native vessels. Forty-nine of 55 (89%) venous grafts could be successfully dilated, and in 3 internal mammary artery grafts, a stenosis reduction greater than 50% was achieved. In 65 of 88 (74%) grafted native arteries, dilation success was achieved. Twenty-seven of 36 (75%) patients with prior bypass surgery to other arteries had successful angioplasty of nongrafted native arteries. Three patients underwent emergency bypass surgery after dissection and acute occlusion: one of them died in cardiogenic shock secondary to acute myocardial infarction. The angiographic success rate in grafts was slightly higher than in native arteries (90% vs 74%). These data indicate that percutaneous transluminal coronary angioplasty in patients after bypass surgery is possible at a low risk (3%) and constitutes an effective therapy in symptomatic patients.

Aged↗

PubMed1992

[Ventricular late potentials in athletes].

Ventricular late potentials detected by signal averaging have a high predictive value for the origin of malignant ventricular tachyarrhythmias in patients with coronary artery disease. We examined 35 male sportsmen aged from 22 to 33 years. Clinical examination, ECG at rest, echocardiography and signal averaging were performed. In nine of the 35 sportsmen (26%) ventricular late potentials were detected. In a control group of 20 nonsportsmen none had late potentials. The nine sportsmen with late potentials all had electrocardiographical and echocardiographical signs of left-ventricular hypertrophy. Of the 26 sportsmen without ventricular late potentials five had left-ventricular hypertrophy. Ventricular late potentials are not rare in sportsmen. They seem always to appear together with left-ventricular hypertrophy.

Adult↗

PubMed1992

[Differences in the non-invasive assessment of left ventricular filling in patients with dilated cardiomyopathy using Doppler echocardiography and radionuclide angiography].

Doppler echocardiography and radionuclide angiography were shown to provide valuable tools with comparable functional parameters for the noninvasive assessment of left ventricular (LV) diastolic function in patients with coronary artery disease or LV hypertrophy. In order to examine the influence of an impaired systolic function on both methods, we studied LV filling simultaneously by Doppler echocardiography and radionuclide angiography in 47 patients with idiopathic dilated cardiomyopathy and stable sinus rhythm. The Doppler echocardiographic peak velocities (VE, VA) and radionuclide angiographic peak filling rates (PFRFF, PFRA) normalized to either left ventricular enddiastolic volume or stroke volume were measured and systolic function was assessed by obtaining the ejection fraction (EF) with the radionuclide angiography. Patients were divided into two groups with moderately (group 1: EF > or = 35%) or severely impaired (group 2: EF < 35%) systolic function. In group 2 the PFRFF (1.8 +/- 0.5 vs. 3.3 +/- 0.8 SV/s; p < 0.01) and PFRA (1.2 +/- 0.6 vs. 2.5 +/- 1.0 SV/s; p < 0.01) were both lower than in group 1, as was the Doppler echocardiographic VA (0.44 +/- 0.20 vs. 0.63 +/- 0.17 m/s; p < 0.01). However, VE was increased with reduced systolic function (0.75 +/- 0.20 vs. 0.53 +/- 0.16 m/s; p < 0.01). No relation was found between PFRFF and VE and only a weak relation between the atrial filling parameters of Doppler echocardiography and radionuclide angiography. The peak filling rates were closely correlated with the systolic function (PFRFF:r = 0.86; p < 0.001) and were reduced with an impaired systolic function.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗

PubMed1992

Changes in heart rate during obstructive sleep apnoea.

The mechanisms behind the decrease in heart rate during apnoeas in patients with obstructive sleep apnoea (OSA) are little known. Recent findings in animal experiments indicate that stimulation of the upper airway activates postinspiratory and cardiac vagal neurones in the medullary respiratory centre, causing alterations in heart rate and respiratory rhythm. Since OSA leads to a collapse of the airway and consequent stimulation of upper airway receptors, we studied the interrelations between heart rate and respiratory rhythm during apnoea and during negative intrathoracic pressure generated by the Mueller manoeuvre (MM). Fifteen patients with OSA (apnoea hypopnoea index (AHI) 45 +/- 28.h-1) were studied by polysomnography, during a MM and a Valsalva manoeuvre, each of 15 s duration. The heart rate decrease (delta HRA) and the increase in total respiratory cycle duration (TOT) were evaluated during apnoea in non-rapid eye movement (REM) sleep. Patients with OSA demonstrated a decrease in heart rate during apnoea (-14.4 +/- 9.0 beats.min-1), and during MM (-11.5 +/- 13.5 in OSA vs 3.1 +/- 7.8 beats.min-1 in a control group). TOT increased during apnoea (4.6 +/- 3.1 s). There was a significant correlation between delta HRA and AHI (r = -0.64) as well as between delta HRA and increase in TOT (r = 0.62). These findings indicate that upper airway obstruction may cause an activation of receptors at the site of airway collapse or distortion leading to changes in heart rate and respiratory rhythm.

Female↗

PubMed1992

Myocardial distribution of indium-111-antimyosin Fab and technetium-99m-sestamibi in experimental nontransmural infarction.

Early revascularization in acute myocardial infarction results in normal, necrotic and partially damaged and partially salvaged ("intermediate") myocardium. By combining a perfusion tracer and a marker for myocardial injury, we attempted to differentiate between these three types of cardiac tissue. The LAD was occluded in nine pigs for 45 min and then reperfused. After 48 and 72 hr, 74 MBq 111In-antimyosin Fab and 740 MBq 99mTc-sestamibi, respectively, were injected intravenously. Normally perfused myocardium was labeled with fluorescein and the heart excised. Three to four slices were cut from the apex. Tetrazolium staining revealed the zone of necrosis. Tracer distribution on double-nuclide scintigrams of the slices also reflected the three different myocardial zones. Guided by fluorescence and macrohistochemistry, tissue samples were excised from each zone. In relation to normal myocardium, mean activity in the intermediate zone was 0.82 +/- 0.20 for 99mTc-sestamibi and 2.84 +/- 1.31 for 111In-antimyosin Fab. Activity in necrotic myocardium was 0.30 +/- 0.19 and 3.95 +/- 2.47, respectively. These results show that 111In-antimyosin Fab fragments not only accumulate in necrotic but also in intermediate myocardium. Therefore, an overestimation of infarct size may occur if 111In-antimyosin Fab fragments are used alone without a perfusion tracer.

Animals↗