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Biomedical subjects

R Funck

Publications and source records attributed to R Funck.

18 recordsLinked to original sources
PubMed1999

Heart rate variability in carcinoid heart disease.

Time domain heart rate variability measurements and echocardiographic studies were performed in 35 patients with carcinoid syndrome. Carcinoid heart disease was present in 18 patients (51%). Heart rate variability parameters (standard deviation of all normal RR intervals, percentage of the number of pairs of adjacent normal RR intervals differing by >50 ms) were significantly reduced in patients with than in those without carcinoid heart disease.

Adult↗
PubMed1999

Complications of third-generation implantable cardioverter defibrillator therapy.

To determine the incidence of complications of third-generation implantable cardioverter defibrillator (ICD) therapy, 144 patients were prospectively studied who underwent first implant of third-generation devices (i.e., ICD systems with biphasic shocks, ECG storage capability, and nonthoracotomy lead systems). During 21 +/- 15 months of follow-up, 41 (28%) patients had one or more complications. No patient died perioperatively (30 days) and no ICD infection was observed during follow-up. Complications included bleeding or pocket hematoma (hemoglobin drop > 2 g/dL) in 5 (3%) patients, prolonged reversible ischemic neurological deficit in 1 (1%) patient, postoperative deep venous thrombosis of leg in 1 (1%) patient, pneumothorax in 2 (1%) patients, difficulty to defibrillate ventricular fibrillation intraoperatively in 2 (1%) patients, generator malfunction in 1 (1%) patient, arthritis of the shoulder in 3 (2%) patients, and allergic reaction to prophylactic antibiotics in 2 (1%) patients. A total of seven lead related complications were observed in six (4%) patients including endocardial lead migration in four (3%) patients. Twenty-three (16%) patients received inappropriate shocks for supraventricular tachyarrhythmias (n = 13), non-sustained ventricular tachycardia (VT) (n = 7), or myopotential oversensing (n = 3). We conclude that serious complications such as perioperative death or ICD infection are rare in patients with third-generation ICDs. Lead-related problems and inappropriate shocks during follow-up are the most frequent complications of third-generation ICD therapy. Recognition of these complications should promote advances in ICD technology and management strategies to avoid their recurrence.

Defibrillators, Implantable↗
PubMed1998

Simplified implantation of single-lead pectoral cardioverter defibrillators using device-based testing.

Device-based testing of single-lead pectoral defibrillators (defibrillation efficacy testing without an external defibrillation system after complete implantation of the device) resulted in an adequate defibrillation threshold (< or = 20 J) in 45 of 50 study patients (90%). Mean surgical implantation time (skin to skin) was 62 +/- 29 minutes without perioperative mortality and without implantable cardioverter defibrillator infection during follow-up. Thus, device-based testing appears to be a simple and safe method to test defibrillation efficacy of single-lead pectoral defibrillators.

Adolescent↗
PubMed1998

Interactions between pacemakers and security systems.

Electromagnetic fields arising from a variety of different sources have been shown to interfere with normal pacemaker function. This study evaluated the possible interactions between two modern security systems and different pacemaker types. Fifty-three patients (27 single chamber pacemakers, 25 dual chamber pacemakers) have been tested routinely for their pacemaker function. Thirty-eight patients presented with unipolar sensing and 15 with bipolar sensing. The patients were asked to walk through an installed security system, an antitheft device, and electromagnetic access device with different field strengths while a six-channel ECG monitored the patients. The pacemaker systems were first measured in their basic programmed modes, then the intervention frequency was changed to 100/min and, thereafter, the maximum sensitivity without T wave oversensing was added. In the security system with the highest field strength (2,700 mA/m), a pacemaker malfunction could be observed in 13% of the monitored patients. In one case, a pacemaker (VVIR) switched to ventricular safety pacing (VOO mode). In the security system with the lower field strength (1,600 mA/m) we found a pacemaker malfunction in 4% of the tested patients. In the antitheft device (50 mA/m), in the electromagnetic access device (300 mA/m), and in pacemaker systems with bipolar sensing, none of these dysfunctions were observed. Phantom programming as described previously did not occur in any of the systems. Persons who are often in the vicinity of security systems should be equipped with a bipolar pacemaker system. Our findings indicate that patients with pacemakers should avoid contact with security systems.

Adult↗
PubMed1996

Effect of the renin-angiotensin-aldosterone system on the cardiac interstitium in heart failure.

The interaction of the renin-angiotensin-aldosterone system (RAAS) and cardiac growth is of great interest in chronic heart failure. The pressure or volume overloaded heart shows a hypertrophic growth of the myocardium, i.e., an enlargement of cardiac myocytes. In addition, cardiac fibroblast activation is responsible for the accumulation of fibrillar type I and type III collagens within the interstitium and adventitia of intramyocardial coronary arteries. This remodeling of the cardiac interstitium represents a major determinant of pathological hypertrophy in that it accounts for abnormal myocardial stiffness, leading to ventricular diastolic and systolic dysfunction and ultimately the appearance of symptomatic heart failure. The growth of cardiac fibroblasts is not primarily regulated by the hemodynamic load. In vivo and in vitro studies suggest that the effector hormones, angiotensin II and aldosterone, of the RAAS are primarily involved in regulating the structural remodeling of the myocardial collagen matrix. In cultured adult cardiac fibroblasts, angiotensin II and aldosterone has been shown to stimulate collagen synthesis while angiotensin II additionally inhibits matrix metalloproteinase I activity, which is the key enzyme for interstitial collagen degradation in the myocardium. These findings may serve as rationale for a remedial therapy with angiotensin converting enzyme inhibition or blockage of the RAAS in congestive heart failure in patients with hypertensive heart disease, post myocardial infarction or with dilated cardiomyopathy.

Animals↗
PubMed1996

Influence of D-net (European GSM-Standard) cellular phones on pacemaker function in 50 patients with permanent pacemakers.

The widespread use of cellular phones in the last years has prompted some recent studies to suggest an interference of pacemaker function by cellular phone usage. To determine the risk of pacemaker patients using D-net cellular phones, we tested 50 patients with permanent pacemakers after routine pacemaker check by short phone calls using a cellular phone (Ericsson, D-net, frequency 890-915 MHz, digital information coding, equivalent to the European Groupe Systemes Mobiles standard). A six-channel surface ECG was continuously recorded from each patient to detect any interactions between pacemakers and cellular phones. Phone calls were repeated during the following pacemaker settings: (1) preexisting setting; (2) minimum ventricular rate of 90 beats/min and preexisting sensitivity; and (3) minimum ventricular rate of 90 beats/min and maximum sensitivity without T wave oversensing. Only 2 (4%) of 50 patients repeatedly showed intermittent pacemaker inhibition during calls with the cellular phone. Both pacemakers had unipolar sensing. Therefore, although interactions between cellular phone use and pacemaker function appear to be rare in our study, pacemaker dependent patients in particular should avoid the use of cellular phones.

Aged↗
PubMed1996

[Indications for transmyocardial laser therapy].

In symptomatic endstage coronary artery disease after full medical therapy (antianginal drugs, betablockers and ACE-inhibitors) further therapeutical options both for the interventional cardiologist with little hope for improvement by PTCA, stent, rotablation and atherectomy and for the cardiac surgeon with bypass surgery and endarterectomy are not available by definition due to the diffuse arteriosclerotic vessel morphology. In those patients one can therefore consider transmyocardial laser therapy (TMR) as the ultimate treatment option. It then is primarily a palliative measure to reduce the patient's symptoms. Improving perfusion and prognosis remains the most important goals, however. TMR can be utilized as the only revascularizing treatment measure or in combination with CABG or PTCA. According to data from international registries, few controlled and several non controlled studies and our own registry in Marburg with now 101 patients improvement of angina and/or dyspnoea can be expected in more than 60% of patients with end stage coronary artery disease (CAD). The patient cohort comprises symptomatic individuals after CABG or multiple PTCAs or with diffuse CAD in diabetes mellitus or with most severe hypercholesterinemia. We consider these above mentioned criteria as the only validated criteria to enter patients with endstage CAD in our controlled study. Hypothetical options for treatment by TMR such as vasculopathies after heart transplantation, cardiomyopathies under the notion of a possible but not proven microangiopathy are not accepted in our institution at present. Before TMR all patients are assessed for their angina class according to the Canadian Cardiac Society (CCS I-IV)) and their exercise capacity according to the New York Heart Association classification (NYHA I-IV) and reassessed regularly after 3, 6 and 12 months. Thallium/Te MIBI scans at rest- and whenever possible at exercise as well as stress echocardiography are carried in the patients to assess symptomatic improvement, alterations in myocardial perfusion and functional efficacy by TMR. By intermediate analysis the 101 patients of our registry more than 60% of the patients had improved their angina class by at least one classe, some patients have improved perfusion as assessed by scintigraphy, which makes at present a trend but not yet a significant difference, whereas central hemodynamics and ejection fraction remained virtually unchanged in most patients reassessed after TMR. In our analysis mortality of the 101 TMR patients was assessed and plotted on Kaplan Meier survival curves. Mortality at 6 months was 11%. When compared to a historical group of patients with identical CCS and comparable NYHA classes, who were worked up in the manner of a case control study, the TMR mortality was marginally but not yet significantly lower than one would expect from these control patients with terminal CAD treated purely by medication: Their 6 months mortality was 14%. Remarkably but not unexpectedly patients with comparable CCS classes, who could still be treated by PTCA and/or CABG had a significantly lower 6 months mortality than TMR patients or patients on antianginal drugs only. The pathophysiological mechanisms for the symptomatic improvement by laser therapy are not yet fully understood. The 1 mm transmyocardial channels created by the CO2 laser have been postulated to permit perfusion from the ventricular cavity and to seek connection to capillaries and vessels present in the malperfused myocardium thus improving the perfusion by newly created connections and sinusoids from the ventricular cavity. Although there is clear evidence for the presence of open channels acutely and within a few days after TMR therapy little evidence in man is as yet available on the question whether the channels remain open in the long run and, if so, whether they can actually improve perfusion to a substantial degree...

Angioplasty, Balloon, Coronary↗
PubMed1995

The renin-angiotensin-aldosterone system and myocardial collagen matrix remodelling in congestive heart failure.

In chronic heart failure, various regulatory systems including the Frank-Starling mechanism, the neuro-hormonal response, cardiac growth and peripheral oxygen delivery may be operative. Recently, the inter-relationship of the renin-angiotensin-aldosterone system (RAAS) and cardiac growth has drawn clinical interest. In the pressure-or volume-overloaded heart, the development of myocyte growth is primarily dependent on ventricular loading. Non-myocyte cell growth involving cardiac fibroblasts may also occur but this is not primarily regulated by the haemodynamic load. Cardiac fibroblast activation is responsible for the accumulation of fibrillar type I and type III collagens within the interstitium and adventitia of intramyocardial coronary arteries. In addition to relaxation abnormalities due to impairment of sarcoplasmic Ca(2+)-ATPase activity, this remodelling of the cardiac interstitium represents a major determinant of pathological hypertrophy in that it accounts for abnormal myocardial stiffness, leading to ventricular diastolic and systolic dysfunction and ultimately the progression of symptomatic heart failure. The effector hormones of the RAAS, angiotensin II (AngII) and aldosterone (Aldo), appear to be primarily involved in promoting the adverse structural remodelling of the myocardial collagen matrix. In cultured adult cardiac fibroblasts, AngII and Aldo have been shown to stimulate collagen synthesis while AngII additionally inhibits matrix metalloproteinase I activity, which is the key enzyme for degradation of fibrillar collagen in the cardiac interstitium, leading to excessive collagen accumulation. These findings may serve as rationale as to why angiotensin converting enzyme inhibition or blockade of the RAAS represents such remedial therapy beyond the effect of simply unloading the heart in patients with congestive heart failure.

Adult↗
PubMed1995

Pharmacological modulation of cardiac fibroblast function.

The cardiac interstitium is composed of nonmyocyte cells and a structural protein network which plays a dominant role in governing the structure, architecture, and mechanical behavior of the myocardium. The heterogeneity in myocardial structure, created by the altered behavior of nonmyocyte cells, particularly cardiac fibroblasts which are responsible for myocardial collagen metabolism and fibrous tissue accumulation, may largely explain the appearance of diastolic and/or systolic myocardial failure. Regulatory mechanisms that are related to the fibrous tissue response in various cardiovascular diseases, e.g., hypertensive heart disease, dilated cardiomyopathy or post myocardial infarction, are of primary clinical interest. A better understanding of the hitherto neglected role of cardiac fibroblasts in mediating an adverse structural remodeling of the myocardium will lead to specific pharmacologic agents that interfere with the fibrous tissue response. Several lines of evidence based on in vivo and in vitro studies suggest that circulating and tissue renin-angiotensin-aldosterone systems (RAAS) are involved in the structural remodeling of the nonmyocyte compartment, including the cardioprotective effects of angiotensin converting enzyme (ACE) inhibition or aldosterone receptor antagonism that was found to prevent myocardial fibrosis in the rat with renovascular or genetic hypertension. In cultured adult cardiac fibroblasts, an angiotensin (Ang)II- or aldosterone-mediated dose-dependent increase in collagen synthesis could be completely abolished by the use of AngII type 1 or mineralocorticoid receptor antagonists, respectively. Likewise, the AngII-mediated decrease in the activity of matrix metalloproteinase 1, the key enzyme for interstitial collagen degradation, could be antagonized by AngII receptor blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1994

Gd-DOTA as a gastrointestinal contrast agent for gastric emptying measurements with MRI.

Current MR meal markers may interfere with gastric motility and secretion restricting the use of MRI in the measurement of gastric physiology. We therefore evaluated Gd-DOTA as a liquid phase marker, in vitro by determining dissociation, and adherence to the solids, and in vivo by simultaneous MRI (0.35 T scanner, multiple T1-weighted sections of the upper abdomen) and double indicator (perfusion marker PEG 4000, meal marker 99mTc-DTPA) measurements of emptying and secretion, following ingestion of 500 ml 10% glucose. In vitro Gd-DOTA was stable at a pH > 2 with < 2% dissociation at 24 h during incubation with HCl. Dissociation during incubation with HCl was linearly dependent on H+ concentration (0.77 < pH < 2.02). Less Gd-DOTA was absorbed onto the solid phase than 99mTc-DTPA (25% cf 36%). In vivo Gd-DOTA marked gastric contents provided strong positive contrast. Similar emptying curves were observed with both MRI and double-indicator techniques (r = 0.987, P < 0.001). Gd-DOTA has the potential to be a useful liquid phase contrast agent in MR studies on gastric function.

Adult↗
PubMed1994

[Aortic and mitral valve endocarditis after infection of the pacemaker pocket].

The case of a 76-year-old diabetic patient with known aortic valve sclerosis is reported. One week after implantation of a permanent pacemaker system (indication: 2nd degree AV-block type Mobitz) he developed fever. Large endocarditic vegetations were found on the aortic and mitral valve (blood cultures: were positive for Staphylococcus aureus). Also from the pacemaker bed Staphylococcus aureus was isolated and an antibiotic treatment including vancomycin was started. Nevertheless the patient developed insufficiencies of both the aortic and mitral valves and became hemodynamically unstable. Due to cerebral embolisms and further deterioration of the patient's overall clinical state the already planned operative replacement of the aortic and mitral valve could not be performed. The patient died because of left ventricular failure after pacemaker infection which was complicated by endocarditis.

Aged↗
PubMed1994

[Biventricular inflow tract compression by chronic organized hemopericardium in Caplan syndrome].

We report the case of a 59-year old patient with the rare combination of silicosis and rheumatoid arthritis, which is called Caplan's syndrome. The patient presented with right heart failure caused by a pericardial tumor compressing the right and the left ventricle. By means of several imaging techniques it was possible to elucidate the topographic relations of the tumor. Definite signs of malignant growth were not found. Despite his elevated perioperative risk we decided to operate on the patient. During the operation macroscopic and histologic evidence revealed that the tumor was not a neoplastic process but consisted of an organized hemopericardium. This demonstrates that pericarditis in rheumatoid arthritis can be hemorrhagic and can mimick a malignant pericardial tumor. The decision to operate was first supported by the findings of the applied imaging techniques, the normal endomyocardial biopsy, and the clinical course and were later confirmed in situ.

Caplan Syndrome↗
PubMed1994

[Malignant angiosarcoma of the right atrium in pregnancy. Diagnostic and therapeutic problems].

Primary tumors of the heart, in contrast to secondary metastatic tumors show a very rare occurrence. About 25% of all primary cardiac tumors are malignant with angiosarcomas being the most frequent type of tumor. The clinical presentation include pericardial tamponade by hemorrhagic pericardial effusion, right heart failure, lung embolism and thoracal pain. Diagnostic procedures include echocardiography, magnetic resonance imaging, CT scan, angiography, pericardioscopy and finally surgical exploration. We report on a 27-year old pregnant woman (23rd week) with a malignant primary angiosarcoma of the right atrium. The patient was admitted to the hospital with progressive shortening of breath due to pericardial tamponade from pericardial effusion. A tumor of the right atrium was detected by echocardiography. Diagnostic procedures had to consider the pregnancy of the patient. Transesophageal echocardiography, magnetic resonance imaging and finally angiography of the right heart with tumor biopsy were performed. Histological examination did not show any signs of malignancy. After corticosteroids pericardial effusion disappeared. Surgical exploration of the tumor was not performed because of the pregnancy. Two weeks later the patient underwent emergency surgery because of progressive heart failure due to obstruction of the tricuspidal valve by the tumor. Thereby intrauterine death of the fetus occurred. The tumor was removed and the right atrium was reconstructed using a Dacron patch. Adjuvant chemotherapy was performed. Eight months later the tumor recurred and heart transplantation was performed. two months later pulmonary metastases were found. the patient died 20 months after onset of symptoms. This is a rare case of the very unusual coincidence of pregnancy and a primary malignant heart tumor.

Adult↗
PubMedDate not supplied

[Paradoxic occurrence of symptoms of rheumatic fever after thrombolytic therapy with streptokinase--a case of delayed hypersensitivity?].

We report the case of a 51-year-old patient with a Paget von Schrötter-Syndrome of the right arm who underwent a successful lysis therapy with 9 x 10(6) IU streptokinase (Streptase) i.v. over 3 days. 36 h after ending the lysis therapy he developed a generalized eczema, which was interpreted as a drug-induced allergic reaction of the arthus type (Coombs III). He received methylprednisolone p.o. with an initial dose of 40 mg, tapered to 0 over 5 days. One day after the efflorent rash the patient developed fever for 12 h (with 38.8 degrees C maximum) and a gonarthritis of the left knee, and 24 h later of both knees. An echocardiogram showed a small pericardial effusion without hemodynamic influence. On the following 2 days a minimal proteinuria of 0.28 and 0.22 g/l was found. Subsequently and after a follow-up of 2 years, the patient was totally free of pathologic clinical and laboratory findings. We interpret this unusual case as a delayed hypersensitivity reaction to streptokinase with a paradoxical occurrence of clinical symptoms formally fulfilling the diagnostic criteria of "rheumatic fever".

Arthritis, Reactive↗