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Biomedical subjects

C Weinhold

Publications and source records attributed to C Weinhold.

At least 37 records · Page 2Linked to original sources
PubMed1993

Long-term results of pacemaker therapy after orthotopic heart transplantation.

The objectives of this study were to identify: (1) the indications for pacemaker implantation; (2) the long-term survival; (3) the percentage of bradyarrhythmias below 50 beats/min persisting for more than 3 months; and (4) the variables predicting persistent bradyarrhythmias following orthotopic heart transplantations. During the recent decade (August 1, 1981 through December 31, 1991), 237 patients underwent orthotopic heart transplantation at our institution. Twenty-six recipients (11%) showed evidence of a symptomatic bradyarrhythmia due to sinus node dysfunction (n = 25) or complete heart block (n = 1), which required insertion of a permanent pacing device. During a mean follow-up period of 17.2 months (range 3 to 57 months), five patients (19%) died and one was lost to follow-up. Actuarial survival at 1 and 4 years were 81% and 65%, respectively, as compared to 79% and 69%, respectively, in patients without permanent pacemakers. Holter monitoring after 3 months (n = 25) and 1 year (n = 14) showed a spontaneous heart rate below 50 beats/min in six (24%) and three patients (18%), respectively. None of the tested variables predicted the necessity of initial pacemaker implantation. However, in patients requiring permanent pacing for a period longer than 3 months, ischemic time of the donor heart was found to be significantly longer as compared to the other patients (221 +/- 76 min vs 137 +/- 91 min, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Changes in lymphocyte subsets and mitogen responsiveness following open-heart surgery and possible therapeutic approaches.

Septic multi-organ failure represents a common cause for operative mortality following open-heart surgery. One major reason might be the depression of cell-mediated immunity. The purpose of this prospective randomized trial was to quantify and specify the effects of open-heart surgery on cell-mediated immune mechanisms. In addition, the immunorestorative potential of a combined immunomodulatory therapy with the cyclooxygenase inhibitor indomethacin and the thymomimetic substance Thymopentin versus single drug administration of indomethacin was investigated. Twenty patients were given indomethacin for the first 5 postoperative days (group A). Another 20 patients also received Thymopentin perioperatively and on the second and fourth postoperative days (group B), while 20 patients underwent conventional therapy (group C). Cell-mediated immune response was quantified in vitro by measuring CD3+ T-lymphocytes and their subsets, CD4+ T-helper and CD8+ T-suppressor cells. Lymphocyte responsiveness to a specific (Antigen-Cocktail) and non-specific mitogen (phytohemagglutinin) provided information about the quality of cell-mediated immune response. On the first postoperative day CD3+ T-lymphocyte counts and Antigen-Cocktail-induced lymphocyte proliferation decreased significantly in all groups. The number of CD4+ T-Helper cells fell significantly only in groups A and C, while the decrease in group B was not statistically significant; the same applied to phytohemagglutinin-induced lymphocyte response. The CD4+/CD8+ ratio was significantly depressed only in group C, decreased slightly in group A and did not change as compared to baseline values in group B. All investigated parameters remained significantly depressed until the seventh postoperative day in group C.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Haemodynamic and oxymetric investigations on patients under rate-responsive dual-chamber stimulation during exercise.

Rate-response dual-chamber pacing combines the advantages of atrio-ventricular synchrony and rate adaptation in patients suffering from binodal disease. However, it is not known if patients really benefit from the additional rate response under exercise conditions. Therefore, 15 patients suffering from binodal disease received rate-responsive dual-chamber pacemakers. 1, 3, and 6 months postoperatively haemodynamic parameters and oxygen consumption were measured during treadmill ergometry under conventional (DDD) and rate-modulated AV-universal stimulation (DDDR). Using the NCCOM3-R7 (Osypka) technique, rate (f), cardiac index (CI), stroke volume index (SVI), and the end-diastolic volume index (EDVI) were determined non-invasively. Oxygen consumption (VO2) was measured with the Biotec Oxysuper. Based on preoperative status (NYHA) and ventricular contractility, which was determined by means of echocardiography, the patients were divided into two groups: Group I (n = 8) with normal ventricular contractility demonstrated a moderate increase of intrinsic heart rate during exercise. Group II (n = 7) with impaired ventricular contractility showed only a slight or no increase in intrinsic heart rate. When comparing DDD and DDDR pacing a significant increase of CI and VO2 was found for the rate-modulated pacing mode in group II. The reverse was found for patients of group I. The difference between the two groups was statistically significant. According to these results, only patients with nearly no increase in intrinsic sinus heart rate and impaired ventricular function can be expected to benefit from the additional rate-adaptation of a dual-chamber pacemaker.

Adult↗
PubMed1988

The benefit patients derive from aortocoronary reoperation.

There is an increasing incidence of aorto coronary reoperation necessitated by intractable angina which averages 2% of 4676 initial bypass procedures. Graft obliteration, graft stenosis or progression of disease led to recurrence of symptoms in 96 patients (84 male, 12 female) who underwent a second operation. Not all occluded or stenotic bypasses were feasible for reoperation. Hospital mortality (30 days) was higher than after initial CABG, but could be reduced from 12.1% to 4.8%. Subjective and objective follow-up investigations were obtained in 77 of 84 survivors and demonstrate that successful reoperation is about 10% lower in patients with a malignant form of atherosclerosis (60%) than in patients who only suffer from occluded grafts or new proximal significant stenoses in previously unbypassed vessels (70%).

Adult↗
PubMed1988

Subsensitivity of the failing human heart to isoprenaline and milrinone is related to beta-adrenoceptor downregulation.

The number of cardiac beta-adrenoceptors and the positive inotropic effect of isoprenaline and milrinone were measured in cardiac membranes and isolated, electrically driven muscle strips from nonfailing donor hearts and from patients with mitral valve disease (NYHA II-III), ischemic heart disease, and dilated cardiomyopathy (NYHA IV). In nonfailing hearts, the number of beta-adrenoceptors were 41.5 fmol/mg protein (mean, n = 3). In ischemic heart disease and NYHA II-III, there was a loss of cardiac beta-adrenoceptors (22.1 fmol/mg protein, mean, n = 3; 23.2 +/- 2.7 fmol/mg protein, n = 30), respectively. In NYHA IV, there was a pronounced reduction of the number of cardiac beta-adrenoceptors to 12.1 +/- 1.5 fmol/mg protein (n = 15). The Kd value did not differ in either group. Correspondingly, the positive inotropic effect of isoprenaline was more pronounced in nonfailing myocardium, reduced in NYHA II-III and ischemic heart disease and almost blunted in NYHA IV. Similar results were observed with the phosphodiesterase inhibitor milrinone. A good correlation of the beta-adrenoceptor density to the maximal positive inotropic effect of isoprenaline and milrinone was observed. Neither the number of cardiac beta-adrenoceptors nor the positive inotropic effect of isoprenaline correlated with the age of the patients. We conclude that the number of cardiac beta-adrenoceptors and the positive inotropic effect of beta-adrenoceptor agonists are reduced in the failing human heart depending on the severity of heart failure. Furthermore, the positive inotropic effect of milrinone is also reduced and related to the reduction of beta-adrenoceptors. The lack of correlation with the age of the patients provides evidence for a predominant role of heart disease rather than aging in the reduction of beta-adrenoceptors and subsensitivity to cyclic AMP-increasing positive inotropic agents in the failing human heart.

Aging↗
PubMed1988

Reliability of atrial screw-in leads.

The aim of this study was to investigate long-term performance of a carbon coated atrial screw-in lead. During implantation of 247 leads of this type we measured an average stimulation threshold of 0.74 (range: 0.2-1.6 V) at 1 ms pulse width. Mean lead impedance came to 446 ohms (range: 263-1000 ohms) resulting in an arithmetical energy consumption of 1.51 microJ (range: 0.1-7.21 microJ). Average P wave amplitude was 3.9 mV (range: 1.3-11 mV). After a mean follow-up of 16.4 months (range: 3-60 months) we found excellent threshold results in 76% of the patients permitting a safety programming at half of nominal value. An additional 14% nominal settings could be retained. With regard to chronic lead impedance of 488 ohms (range: 315-1327 ohms) we calculated an average chronic energy consumption of 10.83 microJ (range: 1.62-22.78 microJ) during safety programming. This made up 34.6% of the corresponding energy consumption during nominal programming. Eighty percent of the patients showed chronic P waves above 2 mV; nearly half of them (n = 94 = 38%) showed a proper sensing function even when programmed to minimal sensitivity settings or above 4 mV. In 19 leads (8%) we observed unsatisfying threshold results requiring high output programmings. All threshold increases occurred within the first year, 84% (n = 16/19) within the first 3 postoperative months. An additional five leads (2%) were found to have a loss of capture, and one (0.5%) a loss of sensing.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon↗
PubMed1988

[Plasma histamine level in the pulmonary vein immediately following the bolus injection of high-dose heparin in the right atrium. A study carried out during aortocoronary bypass surgery].

This study demonstrates a very rapid and short-lasting elevation of plasma histamine concentrations after heparin injection prior to cannulation for extracorporeal circulation during cardiac surgery. Plasma histamine concentrations increased significantly for less than 1 min following bolus injection of heparin into the right atrium. Blood samples were taken from the distal pulmonary vascular bed, i.e. the pulmonary vein. The design of the study enabled us to observe the development of plasma histamine concentrations within very short time intervals and to detect the high peak plasma histamine concentration that may occur, primarily in the pulmonary outstream vessels. Therefore, the histamine found here could originate from intrathoracically located mast cells. It is more likely, however, that the histamine was administered together with the heparin in complex binding, due to purification problems. The amount of histamine found in this study was sufficient to produce mild to severe circulatory effects in all patients receiving a high dose of heparin.

Coronary Artery Bypass↗
PubMed1986

Depressive symptoms and life events in physically ill hospitalized adolescents.

To study life events and depressive symptoms in adolescents hospitalized for physical illness, we administered the Coddington Life Events Survey and the Beck Depression Inventory (BDI) to 43 acutely ill adolescents, 42 chronically ill adolescents, and 140 adolescents from a general population. There were no differences between the three groups in total BDI, Psychological BDI, and Coddington Life Change Categories adjusted for hospitalization. The Somatic BDI was significantly greater in the acutely ill and chronically ill than in the general population sample (p less than 0.01). In the chronically ill, the Family Life Change score correlated with the psychological BDI (r = 0.44, p less than 0.01) but the Undesirable Life Change score did not. In the acutely ill and the general population, the Undesirable Life Change Score correlated with the Psychological BDI (r = 0.44, p less than 0.01), (r = 0.43, p less than 0.01) but the Family Life Change Score did not.

Acute Disease↗
PubMed1986

Surgical treatment of aneurysms of the ascending aorta. Twelve years' experience in 66 patients.

This study presents the results in 66 patients undergoing surgery for concomitant supracoronary vascular interposition and valve replacement carried out at the Department of Cardiac Surgery of the University of Munich, West-Germany, over a period of 12 years (from July 1, 1973 to June 30, 1985) using a technique similar to that described by Wheat. Forty-seven percent of the cases were true aneurysms and 20% chronic dissections. Thirty-three percent of patients had acute dissections. Early mortality was 16% in the total patient population, 9% in the group having true aneurysm and 32% in the group having acute dissection. No early death was observed in association with chronic dissections. The actuarial one-year survival rate in patients with true aneurysm or chronic dissection was 83.6%, and 54.1% in patients with acute dissection. The corresponding 4-year survival rates were 76.4% and 54.1%, respectively. The average improvement according to the New York Heart Association classification was 1.5 grades. These results confirm that the operative approach to ascending aortic aneurysms is superior to medical treatment, with the operative method involving vascular graft without concomitant aortic valve replacement as well as the method described by Wheat having both proved successful.

Acute Disease↗
PubMed1986

Complications in dual chamber pacing: a six-year experience.

In a six-year period (1980-1985), 345 dual chamber pacing systems were implanted in our hospital. Intraoperative complications were rare (n = 5/345 = 1.4%). 25 patients (7%) have died, 11 (3%) were lost to follow-up. A total of 39 patients (13%) showed minor problems, which could be overcome by reprogramming. Another 48 complications (15%) required reoperation. Nearly 70% of those reoperations (n = 31/48) were caused by a malfunction of the atrial lead. This high complication rate of 9% related to all implanted atrial leads could be reduced in the last three years to 2%. We could maintain a dual chamber stimulation mode (DDD, DDI, DVI, VDD) in 396 patients (99%). We conclude that improvements in lead design, pulse generator's programmability, and surgical experience have reduced complication rates to acceptable low values. Meanwhile, dual chamber pacing can be considered as safe as single chamber pacemaker therapy.

Adolescent↗