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Biomedical subjects

H Kreuzer

Publications and source records attributed to H Kreuzer.

At least 163 records · Page 9Linked to original sources
PubMed1990

[Ventricular arrhythmia and late potentials in patients with hypertrophic cardiomyopathy].

Holter monitoring (48 h) and registration of signal-averaged late potentials (method of Simson, high pass filter 40 Hz) were performed in outpatiens with hypertrophic cardiomyopathy. A prevalence of spontaneous ventricular arrhythmias could be determined in 51 patients; the results of 45 patients not taking antiarrhythmic drugs are presented here. 96% of these showed ventricular premature beats, 76% had multiform extrasystoles, 27% showed pairs of ectopic beats and 20% had runs of ventricular tachycardia (more than 3 QRS complexes). Absolute counts of premature beats were low in most patients, but important interindividual differences could be observed: M = 34 extrasystoles/24 h (0-4943). Ventricular tachycardias were of short duration (maximum 11 QRS) with heart rate ranging from 120 to 200/min. All patients were asymptomatic during tachycardia. Signal-averaged late potentials could be registered in 30 patients, 28 of them without antiarrhythmic drug therapy. Mean QRS duration (QRSdur) was 108 +/- 12 ms, mean duration of low amplitude signals (less than 40 microV) in the terminal portion of the QRS (LAdur) was 27 +/- 13 ms, and mean amplitude of the last 40 ms of the filtered QRS (LAamp) was 65 +/- 43 microV. A patient was considered to show late potentials if two of the following criteria were present: QRSdur greater than 120 ms, LAdur greater than or equal to 40 ms, LAamp less than 20 microV. This was found in four patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Is patient education using audiovisual methods helpful?].

In a prospective randomized study we compared the effectiveness of preparatory information with and without a video film show about a planned heart catheterization. 65 patients were included, 5 were later excluded for medical reasons. One group (n = 34) received preparatory disclosure from a standard pamphlet and a personal interview; the other group additionally watched a 14 min video (n = 26). Only the latter group had a significant reduction of anxiety scores. Patients said they received better information from the film than from the pamphlet. Duration of the personal interview did not differ. Viewing the video may improve patient compliance.

Adult↗
PubMed1990

Arguments supporting the use of calcium antagonists in idiopathic dilated cardiomyopathy: theoretical considerations and clinical results.

There is increasing evidence that sarcolemmal disorders in idiopathic dilated cardiomyopathy (IDC), due either to viral infection, catecholamine excess, ethanol intoxication, microcirculatory disorders, or autoimmune responses, induce enhanced Ca2+ inflow. This may lead to mitochondrial Ca2+ accumulation and activation of phospholipase and proteases, resulting in left ventricular dysfunction. The acute beneficial hemodynamic response to diltiazem in IDC patients, in comparison to other calcium blockers, enabled us to perform an open trial investigating the effects of chronic diltiazem (60-90 mg t.i.d.) in patients with IDC. The results of this trial suggested that adjunctive diltiazem in IDC had beneficial effects on mortality, hemodynamics, and symptoms. Thus a multicenter, double-blind, placebo-controlled trial was initiated.

Calcium Channel Blockers↗
PubMed1990

[Short- and long-term results following implantation of the new Wiktor stent in acute coronary occlusion following PTCA].

Ten patients, two women and eight men, were treated with the new balloon-expandable Wiktor Stent for acute coronary occlusion after PTCA. Two patients presented with an acute myocardial infarction. Stents with a diameter of 3.0 or 3.5 mm were implanted into the right coronary artery (n = 7), the left anterior descending (n = 2) artery, and the left circumflex coronary artery (n = 1). Stent implantation in the target segment was successful in all cases. Afterwards, patients received coumadine for 3 months and 100 mg acetylsalicyclic acid per day. We observed one acute occlusion after 8 h. Late occlusion occurred in two patients after cessation of anticoagulation within 3 weeks. Control angiography after 6 months in seven patients revealed stenosis within the stent in two cases.

Aged↗
PubMed1990

[Doppler echocardiography determination of systolic and diastolic function in sequential and ventricular stimulation].

In 16 patients with sequential pacing and partly impaired left-ventricular function (mean shortening fraction 23 +/- 7%), the flow through the mitral and aortic valves were studied with Doppler echocardiography at different AV-intervals, keeping heart rate constant at 70/min. The time-velocity integral of the early and late diastolic filling, the first one-third filling fraction, and the diastolic-filling time were found to be significantly dependent on the length of the AV interval (p less than 0.001). In the left ventricular outflow tract, the maximum stroke volume of 85.6 +/- 28.4 ml was measured at an AV interval of 200 ms. The stroke volume under VOO stimulation (70.5 +/- 24.1 cm) was 17% less (p less than 0.003). There was no correlation between the increase in stroke volume during sequential pacing and M mode or Doppler echocardiographic parameters. Thus, the haemodynamic benefit of sequential pacing cannot be predicted by echocardiography. Doppler echocardiography is useful for determining the AV interval leading to the maximal cardiac output at rest. In the Doppler echocardiographic assessment of left-ventricular function, the influence of the AV interval on diastolic-filling parameters must be considered.

Adult↗
PubMed1990

Prevention of an early re-occlusion after thrombolytic therapy of acute myocardial infarction by ketanserin.

A problem after successful thrombolytic therapy of acute myocardial infarction is the early occurrence of re-occlusions. An incidence between 10 and 30% is reported. All efforts made so far to reduce the re-occlusion rate using a variety of agents have been disappointing. In a pilot study 20 patients with acute myocardial infarction were treated, in whom a successful lytic therapy with urokinase or rt-PA was documented by means of coronary angiography 90 min after the beginning of treatment. Subsequently the patients were heparinised (thrombin time greater than 30 s), and in addition the selective serotonin-2 receptor-blocking agent ketanserin was given intravenously (4 mg/h). After 24 h the occurrence of early reocclusions was investigated by control angiography. None of the 20 patients showed reocclusions. The degree of stenosis in the infarcted vessel was 72% immediately after lytic therapy, and 68% after 24 h. These preliminary results may suggest a possible reduction in the re-occlusion rate after thrombolytic therapy with a combination of heparin and ketanserin.

Adult↗
PubMed1990

Serotonin antagonism in the treatment of cardiac insufficiency.

One approach in the therapy of cardiac insufficiency is the administration of vasodilator substances for afterload reduction. Ketanserin selectively blocks the serotonin-2 receptors and thus inhibits the vasoconstrictor effect of serotonin. A hypotensive action of ketanserin has been documented in several studies. In 10 patients with coronary heart disease and cardiac insufficiency we investigated the haemodynamic effects of ketanserin after 24 h of intravenous administration (4 mg/h) and after 4 weeks of oral therapy (80 mg/day). Five patients received ketanserin for 12 months and were then re-examined. The resting mean arterial pressure dropped from 97.1 to 89.3 mm Hg after intravenous administration (p less than 0.05) and to 89.3 mm Hg after 4 weeks of oral intake (p less than 0.05). The resting mean pulmonary arterial pressure dropped from 15.2 to 12.0 mm Hg after intravenous administration (p less than 0.05) and to 11.7 mm Hg after 4 weeks of oral ingestion (p less than 0.01). Under exercise the pressure dropped from 35.3 to 28.1 mm Hg after intravenous administration (p less than 0.0025) and to 29.9 mm Hg after 4 weeks of oral intake (p less than 0.0025). Heart rate and cardiac output did not show any significant differences. The measured values after 12 months (in 5 patients) did not differ significantly from those measured after 4 weeks. In view of its low side effect liability ketanserin could be used as an afterload-lowering agent in patients with cardiac insufficiency.

Administration, Oral↗
PubMed1990

[What is the position of atherogenesis in current clinical cardiology?].

The Göttingen risk incidence and prevalence studies (GRIPS) are a good example of the fruitful cooperation between experts in lipidology and clinical cardiology. Integrated research by experts in epidemiology, lipidology, genetics, blood pressure regulation and clinical cardiologists is deemed necessary to cope with the multifactorial etiology of atherosclerosis.

Arteriosclerosis↗
PubMed1990

[Spontaneous coronary artery dissection: a rare cause of myocardial infarct].

The case of a 52-year-old female is presented who suffered from myocardial infarction with a prolonged course of symptoms. The angiographic examination revealed a spontaneous dissection of the right coronary artery without evidence for atherosclerotic coronary artery disease. Under medical treatment no further complications occurred. Control angiography showed a spontaneous improvement of the dissection. The characteristic clinical features of this case are compared with the literature data on angiographically visualized spontaneous coronary artery dissections.

Aortic Dissection↗
PubMed1990

[Doppler echocardiography evaluation of left ventricular function in intra-aortic balloon counterpulsation].

Doppler-echocardiographic measurement of transaortic and mitral flow allows an assessment of systolic and diastolic left ventricular performance. To evaluate the hemodynamic effects of intra-aortic balloon counterpulsation (IABP) 10 patients were examined during IABP after myocardial infarction or cardiothoracic surgery. Doppler echocardiographic transaortic (VAo), early (VE) and late (VA) transmitral flow velocities, transaortic velocity time integral (VTIAo), acceleration and deceleration intervals and rates were obtained. The IABP augmentation was changed from 1:1, 1:2 to 1:4 causing no notable change in invasively measured arterial pressures (p greater than 0.05). With constant heart rate the VE/VA ratio was similar in 1:2 and 1:1 mode (1.44 +/- 0.42 vs 1.47 +/- 0.27; p greater than 0.2), whereas VAo and VTIAo were increased (p less than 0.01). A beat-to-beat analysis during 1:2 mode confirmed an increase in VAo (84.1 +/- 13.5 vs 98.3 +/- 16.5 cm/s; p less than 0.01) and VTIAo after the augmenting balloon inflation, but did not confirm any concomitant effect on diastolic transmitral parameters; acceleration and deceleration intervals were not changed. Thus, Doppler-echocardiography was able to detect an increase in transaortic flow during IABP augmentation by beat-to-beat analysis. The increase in VTIAo indicates an elevated cardiac output. A similar instantaneous effect on the diastolic transmitral flow could not be identified.

Blood Flow Velocity↗
PubMed1990

[Estimated relation of Doppler echocardiography parameters of diastolic ventricular function and pulmonary capillary pressure in acute ischemia].

A close relation between the Doppler-echocardiographic transmitral flow signal (TMF) and the left ventricular filling pressure in patients with coronary heart disease (CHD) was described in several reports. The present study investigated the validity of this relation during an episode of acute ischemia induced by coronary angioplasty (PTCA) by simultaneous recording of TMF and mean pulmonary capillary wedge pressure (PCm). Thirty-nine patients were examined at rest, and 33 of them were further studied during a subsequent PTCA of the left anterior descending artery (n = 22) or the right coronary artery (n = 11). The onset of ischemia was evaluated by electrocardiography. The Doppler-echocardiographic parameters of diastolic ventricular function were correlated with PCm; the closest correlation was obtained for the relation between PCm and the ratio of the early/atrial velocity integral (Ei/Ai: r = 0.59; p less than 0.0001), and between PCm and the relative share of the early diastolic velocity integral (Ei%: r = 0.58; p less than 0.0001). A wide confidence interval of individual values did not allow a calculation of PCm from Ei/Ai. By a semiquantitative approach an elevated PCm could be estimated from Ei/Ai greater than 1.5 with a high sensitivity (86%) and specificity (81%). During PTCA an increase of PCm was observed (start: 10.2 +/- 4.8; end: 15.0 +/- 6.5; p less than 0.0001), while Ei/Ai decreased slightly (start: 1.37 +/- 0.41; end: 1.27 +/- 0.51; p = 0.32). With increasing duration of inflation, the correlation between PCm and Doppler-echocardiographic parameters was attenuated.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1989

[Acute myocardial infarct caused by nicotine-induced erythrocytosis].

A 29-year-old heavy smoker presented with an acute myocardial infarction and hematocrit of 70%. At immediate coronary angiography a complete occlusion of the right coronary artery was found. After intracoronary urokinase the coronary arteries were found to be completely normal. Causes for the erythrocytosis other than smoking could be excluded. We conclude that thrombotic coronary occlusion with acute myocardial infarction was caused by erythrocytosis due to heavy smoking.

Adult↗
PubMed1989

[Excimer laser angioplasty in arterial obstructive disease. Clinical experience with guidewire-controlled catheter systems].

Percutaneous transluminal laser angioplasties (PTLA) were performed in nine patients (7 males, 2 females, aged 52-81 years) with peripheral vascular disease, stages IIB-IV (Fontaine's classification), with 75% stenosis (5 patients) or occlusion (4 patients) in the area of the superficial femoral artery. Two catheter systems were used. One was a monofiber catheter (600 microns) with eccentric guidewire, the other a multifiber catheter with 12 concentrically arranged fibres (200 microns each) and a central guidewire. An XeCl-excimer laser (308 nm), with a pulse duration of 50 ns and pulse frequency of 15-30 Hz, served as the laser source. It was possible in all patients to reduce the stenosis of 75-100% to 35-70% or reopen the occlusion without laser-associated complications. To remove the residual stenosis PTLA was followed by balloon dilatation in seven patients and by application of a Simpson atherectomy catheter in one patient: these measures reduced the degree of stenosis to 20-40%.

Aged↗
PubMed1989

Beneficial effects of long-term diltiazem treatment in dilated cardiomyopathy.

There is increasing evidence that chronic enhanced exogenous or endogenous catecholamine stimulation in patients with dilated cardiomyopathy may worsen hemodynamic status and prognosis. The cause of this deterioration may lie in myocellular calcium accumulation and microcirculatory disorders. In a prospective study, the calcium channel antagonist diltiazem was given to 22 patients with dilated cardiomyopathy (60 to 90 mg three times daily) in addition to conventional therapy of digitalis, diuretics and vasodilators. Twenty-five patients received the conventional therapy and served as historical controls. Eight additional patients who were not originally included in this control group received adjunctive diltiazem treatment after initially receiving conventional therapy alone. The three patient groups were similar in all hemodynamic and anamnestic features. Only patients with reduced myofibrillar volume fraction on myocardial biopsy were included in the trial, because they could be expected to show hemodynamic deterioration. The mean survival time was 29 months in the control group, whereas no patient in the diltiazem group died over a mean follow-up period of 15.4 months (p less than 0.001). Mean left ventricular ejection fraction increased from 0.34 to 0.44 (p less than 0.001) and New York Heart Association functional class improved significantly in the diltiazem group and during the diltiazem period in the crossover patients, but deteriorated in the control group. The results suggest that adjunctive diltiazem treatment in dilated cardiomyopathy has beneficial effects on mortality, hemodynamics and symptoms.

Adult↗
PubMed1989

Structure and function of contractile proteins in human dilated cardiomyopathy.

The pathogenesis of reduced systolic left ventricular function in dilated cardiomyopathy is yet unclear. To analyze a possible involvement of contractile protein, function and structure of left ventricular myofibrils were examined in hearts of patients with advanced cardiomyopathy undergoing heart transplantation and in normal control hearts (from renal transplant donors). Myosin and actin content of the left ventricular myocardium was slightly reduced in cardiomyopathic hearts. Myofibrillar polypeptide composition was determined using two-dimensional electrophoresis and immunoblotting. No differences in constituting polypeptides were apparent, including Z-line proteins and proteins of the endosarcomeric lattice. M-line-bound creatine kinase was identical in both groups. Further, basal and maximal myofibrillar adenosine triphosphatase (ATPase) activities were unaltered in dilated cardiomyopathy. The structure of purified myosin was identical in both groups by the following criteria: electrophoretic mobility of native myosin, identical pattern of light chains after isoelectric focusing, identical cleavage peptides of myosin's heavy chain, and identical patterns after immunoblotting of heavy chain cleavage peptides using polyclonal antibodies generated against myosin from normal and cardiomyopathic ventricles. Ca2+-activated, K+-EDTA-activated and actin-activated myosin ATPase activities were identical in control and cardiomyopathic hearts. A structural alteration or functional defect of myofibrils does not seem to be primarily involved in the pathogenesis of reduced myocardial contractility in dilated cardiomyopathy.

Actins↗
PubMed1989

Comparative study on the enhancement of ischemic tolerance by intracoronary pretreatment with three calcium antagonists in pig hearts.

The effect of intracoronary (IC) pretreatment with different calcium antagonists (diltiazem, nifedipine, verapamil) on the development of infarcts was investigated in two experimental series including 35 open-chest pigs. The left anterior descending coronary artery (LAD) was distally ligated for 75 minutes (series A) or for 45 minutes (series B) and was reperfused for 24 hours. Infarct size was determined as the ratio of infarcted myocardium (tetrazolium stain) to the risk region (dye technique). In series A, 20 pigs were pretreated immediately before occlusion with either IC diltiazem (n = 5, 4 mg/2 min), IC nifedipine (n = 5, 0.4 mg/2 min), IC verapamil (n = 5, 1 mg/2 min), or isotonic sodium chloride solution (n = 5). In series B, IC diltiazem (n = 5, 4 mg/2 min), IC verapamil (n = 5, 1 mg/2 min), or isotonic saline solution (n = 5) were administered 8 minutes prior to ischemia. The IC infusion of all calcium antagonists (series A) depressed left ventricular peak pressure, diastolic blood pressure, and dp/dt max and increased heart rate and coronary venous oxygen saturation. The development of infarcts was significantly delayed by IC diltiazem and IC verapamil. Mean infarct sizes (series A) amounted to 62% in the diltiazem group, 88% in the nifedipine group, 40% in the verapamil group, and 94% in the control group. In series B, where a time period of 8 minutes elapsed between pretreatment and induction of ischemia, mean infarct sizes after 45 minutes of ischemia and 24 hours of reperfusion amounted to 47% in the diltiazem group, 4% in the verapamil group, and 76% in control experiments.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

The effect of intracoronary diltiazem on regional myocardial function and development of infarcts in porcine hearts.

The effect of intracoronary (i.c.) pretreatment with diltiazem on regional myocardial function and the development of infarcts was investigated in regionally ischemic, reperfused porcine hearts. The left anterior descending coronary artery (LAD) was distally ligated in 16 pigs for 20-90 min followed by 24 h of reperfusion. Eight pigs were treated with increasing doses of i.c. diltiazem (0.375 mg/min, 0.75 mg/min, 1 mg/min) prior to ischemia. Eight pigs served as controls. Regional myocardial function was assessed by implanted ultrasonic crystals. Infarct size was determined as ratio of infarcted (tetrazolium stain) to ischemic myocardium (dye technique). I.c. diltiazem mainly depressed early systolic shortening (isovolumetric contraction) and lengthening during the first half of diastole. Pretreatment with this calcium antagonist significantly delayed the development of infarcts. In control experiments, a mean infarct size of 74% was found after 45-min ischemia. At that time no infarction was observed in the treated group, where infarcts started to evolve after 60-min ischemia. It is concluded that the favorable action of i.c. diltiazem can mainly be ascribed to a reduced myocardial oxygen consumption at the onset of ischemia.

Animals↗