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Biomedical subjects

H Kreuzer

Publications and source records attributed to H Kreuzer.

At least 73 records · Page 4Linked to original sources
PubMed1995

Ventilation and dyspnoea during exercise in patients with heart failure.

Patients with chronic heart failure have an increased ventilation/carbon dioxide production ratio (VE/VCO2) during exercise. Recently it was discussed whether the cause of this increase was a ventilatory stimulus driven other than by CO2. Dyspnoea during exercise is thought to be related to impaired respiratory function. However, clinical confirmation is scarce. Ninety-two patients (age 51 +/- 9 years) with heart failure due to idiopathic dilated cardiomyopathy exercised on a bicycle ergometer to exhaustion, and measurement of ventilatory gases and Swan-Ganz catheterization were performed. The maximal oxygen consumption corrected for body weight (VO2max. kg-1) was 16.6 +/- 5.5 ml x min-1 x kg-1. The increase in (VE/VCO2) during exercise was related to an increase in respiratory rate (r = 0.43; P < 0.00001) but not to an increase in cardiac index or capillary wedge pressure. Nineteen patients stopped exercising because of dyspnoea. Their maximal tidal volume and VO2max . kg-1 were lower than the 67 patients who stopped exercise because of fatigue (P < 0.001 and P < 0.00001 respectively). Other variables showed no significant difference. In conclusion, the increase in VE/VCO2 during exercise may reflect a non-CO2 driven ventilatory stimulus as it cannot be attributed to increased pulmonary vascular pressures or an insufficient increase in cardiac output leading to a ventilation-perfusion mismatch. Low oxygen uptake is a prominent finding in patients with chronic heart failure who experienced dyspnoea during exercise, and dyspnoea is in part related to impaired respiratory function.

Adult↗
PubMed1995

Effects of heparin on aortic versus venous smooth muscle cells: similar binding with different rates of [3H]thymidine incorporation.

The mechanisms resulting in the high incidence of stenoses of coronary venous bypass grafts are still unclear. Heparin, a potential inhibitor of cellular proliferation, neither inhibits intimal hyperplasia in animal models of vein-to-artery grafting nor prevents graft stenosis when administered to patients. We studied the effects of heparin on cultured pairs of human aortic and venous smooth muscle cells (SMC) obtained during coronary bypass surgery from patients with no history of previous restenosis or graft failure. DNA synthesis was measured as [3H]thymidine incorporation after stimulation with 10% fetal calf serum (FCS). Heparin (100 micrograms/ml) inhibited DNA synthesis of aortic SMC to 64 +/- 14% (mean +/- SEM), whereas it stimulated DNA synthesis of venous SMC to 136 +/- 23% (10% FCS alone = 100%; p = 0.01, Wilcoxon signed-rank test, n = 7). Binding studies with [3H]heparin showed no significant differences of Kd values and number of binding sites per cell between SMC derived from aorta or vein that could account for the lack of heparin inhibition of venous SMC DNA synthesis. These data suggest an inherent difference in the heparin susceptibility that may explain the failure of heparin to inhibit intimal proliferation in vein grafts.

Aorta↗
PubMed1995

Obstructive sleep apnoea and signal averaged electrocardiogram.

Patients with obstructive sleep apnoea demonstrate an increased rate of ventricular arrhythmias. The present study was designed in order to investigate whether these arrhythmias may be related to myocardial injury, since myocardial injury of various aetiologies has been observed to change the signal averaged electrocardiogram (ECG). Signal averaged ECG was registered in 23 patients with obstructive sleep apnoea diagnosed by polysomnography (apnoea index 43 +/- 20 events.h-1, age 55 +/- 10 yrs). QRS duration, root mean square voltage of the last 40 ms of QRS, and low amplitude (< 40 mV) signal duration were determined from the vector magnitude of the QRS, high-pass filtered at 40 Hz. Patients with coronary heart disease or bundle branch block were excluded. No patient showed an abnormal signal averaged ECG. Mean duration of the filtered QRS complex was 96 +/- 9 ms, root mean square voltage 38 +/- 18 microV and low amplitude signal duration 26 +/- 8 ms. These results were not significantly different from 14 snoring subjects with an apnoea/hypopnoea index < 10. Four patients showed no ventricular arrhythmias and six patients had Lown III or IVa in the Holter ECG. Echocardiography revealed increased left atrial (43.7 +/- 4.1 mm) and interventricular septal diameters (11.3 +/- 1.4 mm). In conclusion, obstructive sleep apnoea does not generate a substrate for late potentials in the signal averaged ECG.

Arrhythmias, Cardiac↗
PubMed1995

[Elimination of periodic respiration in heart failure by heart transplantation].

Patients with heart failure are known to demonstrate periodic respiration during sleep. The mechanism behind periodic respiration is thought to be related to left heart enlargement causing an increased transit time between lung and chemoreceptors leading to an oscillation of the feed back loop controlling respiration. Additionally hyperventilation was shown to play an important role. We report of an 18 year old patient with idiopathic dilated cardiomyopathy (left atrial 52 mm, left ventricular end diastolic diameter 69 mm). Polysomnography revealed prolonged transit time and periodic respiration with impaired sleep. Hypocapnia and hyperventilation was demonstrated. Following successful cardiac transplantation periodic respiration was absent and transit time was normal. There was no hypocapnia or hyperventilation. Hypercapnic ventilatory response did no change. These findings support the model of an oscillation of the feed back loop controlling respiration as the main pathomechanism behind periodic respiration.

Adolescent↗
PubMed1995

[Bacterial endocarditis of the transvenous lead of an implantable cardioverter/defibrillator].

A 27-year-old patient carrying a transvenous ICD developed infective endocarditis more than 1 year after surgery. Staphylococcus aureus was isolated from blood cultures. A transesophageal echocardiogram revealed a mobile vegetation on a thrombus attached to the ICD lead in the right atrium. The ICD lead was removed by right anterolateral thoracotomy. This raises the issue of the risk of thrombus formation in patients with intravenous ICD leads and the associated susceptibility to infective endocarditis.

Adult↗
PubMed1995

[Prognostic significance of changes in left ventricular diastolic function in follow-up of dilatative cardiomyopathy].

A total of 39 patients with idiopathic dilated cardiomyopathy (IDC) and sinus rhythm were examined for correlations between clinical course, systolic/diastolic cardiac function, and clinical status according to NYHA class (I-IV). Patients were divided in two groups: group 1 included survivors (n = 28, 49 +/- 11 years) and group 2 the nonsurvivors (n = 7) and transplanted patients (n = 4 transplanted; 48 +/- 10 years). Both groups were examined several times, and data at baseline were compared with those of the last examination. The follow-up period was about 3 years (group 1: 41 +/- 22 months, group 2: 24 +/- 13). Baseline conditions were defined at the time when the diagnosis of IDC was established. Diastolic cardiac function was evaluated by Doppler echocardiography parameters of early (VE) and late diastolic peak velocity (VA), the ratio of VE/VA and early deceleration time (EDT). Data for clinical symptoms (NYHA group 1: 2.5 +/- 0.9 vs. group 2: 2.7 +/- 1.3, NS) systolic [fractional shortening (FS) group 1: 0.17 +/- 0.06 vs. group 2: 0.16 +/- 0.06, NS], and diastolic function (VE, VA, VE/VA) showed no differences between the two groups. Only the EDT was significantly shorter in group 2 (group 1: 196 +/- 64 ms vs. group 2: 119 +/- 43 ms, P < 0.001) when diagnosis was established. During the follow-up period there was an improvement in both groups concerning NYNA class (group 1 from 2.5 +/- 0.9 to 1.9 +/- 0.7, P < 0.005; group 2 from 2.7 +/- 1.3 to 2.1 +/- 0.9, NS). There was a nonsignificant deterioration in systolic function in group 2 (FS, from 0.16 +/- 0.06 to 0.15 +/- 0.06, P = 0.07), which contrasted to an improvement in group 1 (from 0.17 +/- 0.06 to 0.20 +/- 0.08, P = 0.06). VE/VA increased in group 2 (from 1.24 to 1.67 +/- 1.21, P = 0.09) essentially due to a significantly increased VE (from 0.66 +/- 0.2 m/s to 0.85 +/- 0.27 m/s, P < 0.05). EDT remained shorter in group 2 (group 1.198 +/- 55 ms vs. 149 +/- 84 ms, P < 0.05). In conclusion, values of VE > 0.8 m/s, VE/VA > 1.6, and EDT < 150 ms during follow-up were predictors of poor prognosis in patients with IDC. Patients with a long EDT (> 150 ms) had a favorable prognosis for survival.

Adult↗
PubMed1995

Diagnostic value of transesophageal compared with transthoracic echocardiography in suspected prosthetic valve endocarditis.

To compare transthoracic (TTE) and transesophageal (TEE) echocardiography specifically in prosthetic valve endocarditis, 73 consecutive patients (age, 7 to 80 years) with 86 prostheses who had TTE and TEE for suspected endocarditis were analyzed retrospectively. Thirty-four patients proved to have endocarditis according to clinical criteria (pathoanatomical confirmation in 16), the remaining 39 served as controls. In the endocarditis group, a total of 38 (25 mitral, 13 aortic) prostheses were investigated. Vegetations were detected by TTE in 5 (all aortic) and TEE in 28 (20 mitral, 8 aortic) prostheses (13 vs 74%, p < 0.0001). An annular abscess was found on TEE in 1 mitral implant (3%). New perivalvular regurgitation was demonstrated on TTE in 7 (2 mitral, 5 aortic) and on TEE in 16 (10 mitral, 6 aortic) prostheses (18 vs 42%, p = 0.025). All in all, abnormalities suggestive of endocarditis were revealed on TTE in 10 (2 mitral, 8 aortic) and on TEE in 35 (23 mitral, 12 aortic) prostheses (sensitivity 26 and 92%, p < 0.0001). In the control group, TEE was false positive in 1 mitral prosthesis (specificity for TTE and TEE 100 and 97%, respectively; p = NS). These results indicate that TEE is markedly superior to TTE in prosthetic valve endocarditis. The diagnostic advantage is most evident in mitral prostheses. This holds for the detection of both morphologic changes and prosthetic malfunction.

Abscess↗
PubMed1995

[Therapy of Cheyne-Stokes respiration with nocturnal oxygen therapy].

Cheyne-Stokes respiration is common in patients with severe congestive heart failure and is associated with significant nocturnal oxygen desaturation and sleep disruption. The pathogenesis of Cheyne-Stokes respiration in patients with congestive heart failure has been well described and is related to prolonged circulation time between the lung and the carotid body mainly due to increased cardiac dimensions, reduced body stores of oxygen and carbon dioxide, disturbance of ventilation and respiratory control due to arousals and a relatively high hypercapnic ventilatory response. Oxygen is likely to reduce Cheyne-Stokes respiration by increasing oxygen and carbon dioxide stores and reduces the hypercapnic ventilatory response. In the following paper we describe a study designed to determine the impact of nasal nocturnal oxygen on Cheyne-Stokes respiration, sleep, peak oxygen consumption during bicycle exercise, cognitive function evaluated by the trailmaking test and daytime symptoms in patients with severe congestive heart failure. The study is designed as a randomized, cross-over, double-blind, placebo-controlled protocol on about 20 patients with a left ventricular ejection fraction < 35%.

Arousal↗
PubMed1994

Catheter ablation of ventricular tachycardia in 136 patients with coronary artery disease: results and long-term follow-up.

OBJECTIVES: This study attempted to determine the feasibility and long-term efficacy of catheter ablation by means of either radiofrequency or direct current energy in a selected group of patients with coronary artery disease. BACKGROUND: Catheter ablation of ventricular tachycardia has proved to be highly effective in patients with idiopathic and bundle branch reentrant ventricular tachycardia. In patients with coronary artery disease and recurrent sustained ventricular tachycardia resistant to medical antiarrhythmic management, the value of catheter ablation has not yet been established. METHODS: One hundred thirty-six patients with coronary artery disease and one configuration of monomorphic sustained ventricular tachycardia underwent radiofrequency (72 patients) or direct current catheter ablation (64 patients). The mapping procedure to localize an adequate site for ablation included pace mapping during sinus rhythm, endocardial activation mapping, identification of isolated mid-diastolic potentials and pacing interventions during ventricular tachycardia. RESULTS: Primary success was achieved in 102 (75%) of 136 patients (74% of 72 undergoing radiofrequency and 77% of 64 with direct current ablation). Complications were noted in 12% of patients. During a mean (+/- SD) follow-up period of 24 +/- 13 months (range 3 to 68), ventricular tachycardia recurred in 16% of patients. CONCLUSIONS: Catheter ablation of ventricular tachycardia in coronary artery disease is feasible in patients with one configuration of monomorphic sustained ventricular tachycardia. There is no significant difference with respect to the type of energy applied. The follow-up data show that in a selected group of patients with coronary artery disease, catheter ablation offers a therapy alternative.

Adult↗
PubMed1994

[Spontaneous echo contrast in the left ventricle as an indicator for an increased risk of thromboembolism].

A 69-year-old man with coronary heart disease complained of pain in his right flank. He had dyspnoea, cough and fever up to 38.8 degrees C. In addition to various positive indicators of inflammatory disease he had a creatinine concentration of 1.8 mg/dl and an increased activity of lactate dehydrogenase (1655 U/l). The chest radiograph demonstrated pneumonia and computed tomography showed an infarct in the right kidney. The ECG indicated atrial fibrillation with an irregular ventricular rate and left bundle branch block. Echocardiography demonstrated dilatation of the left ventricle and a thrombus adherent to the wall. Transoesophageal echocardiography additionally recorded spontaneous type I echo-contrast, which disappeared after therapeutic heparinization. Cerebral infarctions were shown by computed tomography, undertaken because of neurological symptoms. There were also signs of silent myocardial ischaemia. As a coronary artery bypass operation was contraindicated, percutaneous transluminal balloon angioplasty was attempted but dissection occurred, causing irreversible cardiogenic shock of which the patient died.

Aged↗
PubMed1994

Prognostic value of Doppler echocardiographic assessment of left ventricular filling in idiopathic dilated cardiomyopathy.

The relation of left ventricular (LV) diastolic filling with the clinical outcome in patients with idiopathic dilated cardiomyopathy (IDC) was examined. LV diastolic filling was assessed by Doppler echocardiography in 57 patients with IDC at the time that the diagnosis was established by angiocardiography. Patients were followed for 29 +/- 16 months. Fifteen patients died: 12 due to progressive congestive heart failure and 3 suddenly. Four other patients underwent cardiac transplantation because of progressive heart failure (1-year survival 86%). Patients who died of congestive heart failure or underwent cardiac transplantation had a steep increase and decrease in the early filling phase as compared with survivors; the peak early Doppler velocity was higher (0.84 +/- 0.16 vs 0.65 +/- 0.21 m/s; p < 0.005), and the deceleration time of the early velocity peak was shorter (117 +/- 26 vs 188 +/- 62 ms; p < 0.001) than in survivors. Surviving patients and those who died suddenly showed similar patterns of LV filling. Deceleration time and peak early Doppler velocity were the strongest predictors of survival as compared with systolic function and clinical status in a Cox proportional-hazards analysis. Patients with a shortened deceleration time (< or = 140 ms) had a significantly reduced 2-year survival rate of 52% (confidence interval 34 to 71%) as compared with those with a longer deceleration time (94%; confidence interval 89 to 98%) (p < 0.001). Evidence was presented for a relation between LV filling and survival in patients with IDC.

Actuarial Analysis↗
PubMed1994

Mechanical left ventricular unloading during high risk coronary angioplasty: first use of a new percutaneous transvalvular left ventricular assist device.

A new catheter mounted, transvalvular left ventricular assist device has been designed for percutaneous transfemoral access. The device, the Hemopump [14 French (Fr.) outer diameter], is based on a mixed flow rotary pump and is capable of flow rates of 1.5-2.2 l/min. The pump is inserted using a specialized 16 Fr. femoral introducer sheath. The first application of the percutaneous Hemopump in man was performed in two patients with hemodynamic compromise during high risk coronary angioplasty. In these patients, Hemopump support resulted in hemodynamic stabilization (increase in aortic pressure from 60/42 to 87/61 and from 80/60 to 100/70 mm Hg, respectively) and marked left ventricular unloading (decrease in pulmonary capillary wedge pressure from 25 to 10 and from 14 to 10 mm Hg) during balloon inflation. In both patients, percutaneous transluminal coronary angioplasty (PTCA) could be accomplished successfully. Using the system for periods of about 2 hr in each patient, we observed no vascular, hemorrhagic, or embolic complications. In both patients, only a minor increase in both plasma free hemoglobin and lactate dehydrogenase levels was noted. Our preliminary experiences suggest that the percutaneous Hemopump is safe and effective and may be a powerful alternative to other devices used for supported angioplasty.

Aged↗
PubMed1994

Comparison of hemodynamic and Doppler echocardiographic effects of a new low osmolar nonionic and a standard ionic contrast agent after left ventriculography.

The hemodynamic effects of a new nonionic low osmolar contrast agent (iomeprol) during left ventriculography (LC) was compared with a standard ionic contrast agent (meglumine diatrizoate) in a randomized double blind study in 30 patients with suspected coronary artery disease and normal systolic ventricular function. LV diastolic function was assessed by Doppler echocardiographic recording of the transmittal filling curve and by intraventricular tip-manometry before and within 30 sec of the LC. In the group receiving the ionic contrast agent the systolic pressure fell from 126 +/- 23 to 111 +/- 18 mmHg (P < 0.05), and heart rate increased from 64 +/- 9 to 71 +/- 11 min-1 (P < 0.05), while no such effects were observed with the nonionic contrast agent, indicating differences in the vasodilator properties. The latter caused an increase of the peak early Doppler velocity (52 +/- 11 to 62 +/- 14 cm/sec; P < 0.05). After the ionic contrast agent, the effect on the peak early Doppler velocity was less pronounced, probably due to an interaction with the known depressant effect of the increase in heart rate on the early Doppler velocity. In both groups the left ventricular end diastolic pressure was increased from 7 +/- 3 to 10 +/- 4 mmHg. No significant effects on peak-dp/dt and dp/dt were observed in either group. The nonionic contrast agent iomeprol had no significant effect on systolic arterial pressure and heart rate in contrast to the ionic contrast agent, probably due to a less pronounced vasodilator effect. Despite these differences of the global hemodynamic response, there were similar effects of both contrast agents on LV diastolic filling.

Adolescent↗
PubMed1994

Enterovirus-induced myocarditis: hemodynamic deterioration with immunosuppressive therapy and successful application of interferon-alpha.

In 1985, myocarditis was diagnosed by endomyocardial biopsy in a 53-year-old woman who was free of symptoms of heart insufficiency. Immunosuppressive therapy with azathioprine and prednisolone was prescribed as the patient had deteriorated to NYHA II heart insufficiency in March 1986. When application of immunosuppressive agents was terminated in 1987, serial endomyocardial biopsies revealed no signs of myocarditis, thus indicating effectiveness of immunosuppression. Nevertheless, the patient had worsened clinically and hemodynamically. At follow-up in 1991, the patient had progressed to dilated cardiomyopathy resulting in NYHA III heart insufficiency. Enterovirus infection of the heart was detected by in situ nucleic acid hybridization. In addition, retrospective serology indicated a significant increase of coxsackievirus B2 antibodies between 1985 and 1991. Investigational antiviral therapy with recombinant interferon alpha-2a was tolerated well and a favorable clinical, hemodynamic, and virologic response was observed. Thus, progression of biopsy-proven myocarditis to dilated cardiomyopathy may have been facilitated by immunosuppressive therapy in enterovirus infection. Antiviral therapy might be advantageous in patients with enterovirus myocarditis and dilated cardiomyopathy.

Azathioprine↗
PubMed1994

Autofluorescence spectroscopy using a XeCl excimer laser system for simultaneous plaque ablation and fluorescence excitation.

Laser-induced fluorescence may be used to guide laser ablation of atherosclerotic lesions. This study was performed to evaluate arterial autofluorescence spectroscopy in vitro using a single XeCl excimer laser (308 nm) for simultaneous tissue ablation and fluorescence excitation. The laser beam was coupled to a 600-microns silica fiber transmitting 40-50 mJ/mm2 per pulse. The fluorescence radiation emanating retrogradely from the fiber was collected by a concave mirror spectroscopic analysis over a range of 321-657 nm. The arterial media (n = 26), lipid plaques (n = 26), and calcified lesions (n = 27) of aortic specimens from ten human cadavers were investigated in air, saline, and blood. Whereas the spectrum of calcified lesions changed with the surrounding optical medium, the other spectra remained constant. In air and blood, the spectra of arterial media, lipid plaques, and calcified lesions could be differentiated qualitatively and quantitatively (P < 0.0001). In saline, there was no clearcut spectroscopic difference between lipid plaques and calcified lesions. However, normal arterial media and atherosclerotic lesions (lipid plaques plus calcified lesions) could still be discriminated. Thus spectroscopy and plaque ablation can be combined using a single XeCl excimer laser. These encouraging results should stimulate further studies to determine the potential use of this approach to guide laser angioplasty in humans.

Aged↗
PubMed1994

Scintigraphic detection of inflammatory heart disease.

Inflammatory diseases of the heart encompass myocarditis, endocarditis and pericarditis. This paper discusses the diagnostic potential of scintigraphy in these entities. In myocarditis, indium-111 antimyosin Fab imaging can visualize active myocyte damage and thus contribute substantially to the diagnosis. Antimyosin uptake is also seen in a large subset of patients with dilated cardiomyopathy, indicating ongoing myocyte injury in these cases. In endocarditis, immunoscintigraphy using monoclonal technetium-99m-labelled antigranulocyte antibodies provides useful diagnostic information in patients with equivocal echocardiographic findings. Immunoscintigraphy seems to indicate the floridity of the inflammatory process in endocarditis and may be used to monitor antibiotic therapy. In pericarditis, the clinical value of scintigraphy has not been convincingly demonstrated.

Endocarditis↗