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Biomedical subjects

H Posival

Publications and source records attributed to H Posival.

30 records · Page 2Linked to original sources
PubMed1995

Seven years of experience with the centrifugal pump in patients with cardiogenic shock.

From September 1987 to September 1994 61 patients between 29 and 78 years of age received mechanical circulatory support by means of the Biomedicus centrifugal pump. The patients were divided into three groups by indication: Group I included 15 patients with early postcardiotomy cardiogenic shock and 24 patients with late postcardiotomy cardiogenic shock. Group II 11 patients with therapy-resistant cardiogenic shock following acute myocardial infarction, and Group III 11 patients with cardiogenic shock of other etiologies. Duration of support was 1 to 347 hours. Survival rates were 46.7% and 33.3% in patients with early and late postcardiotomy cardiogenic shock, respectively (Group I), 27.2% in Group II, and 18.1% in Group III. Most frequent complications were bleeding (40%, 58%) and acute renal failure (26.7%, 29.2%) in Group I and multiple organ failure in Groups II and III (64% and 45.5%). Major causes of death were bleeding and multiple organ failure in Group I (37.5%) and multiple organ failure in Groups II and III (87.5% and 50%). Groups II and III (87.5% and 50%).

Adult↗
PubMed1994

Emotional adjustment and perceived locus of control in heart transplant patients.

Orthotopic heart transplantation has been established as a routine clinical operation. In this study, we were interested in: (a) how patients cope emotionally with the situation pre- and postsurgically, especially with regard to anxiety and depression; and (b) whether the patient's perceived locus of control is related to emotional adjustment before and after heart transplantation. Twenty patients who were on the waiting list for heart transplantation with highest priority provided complete psychological questionnaires presurgically and 20 days after surgery when intensive care was no longer required. During the waiting period, patients rated high on depression, state and trait anxiety in comparison with healthy references while ratings on perceived locus of control scales were within the norm ranges. After surgery, heart transplant patients experienced significantly less state/trait anxiety and depression reaching levels which were no longer statistically different from health references. While postsurgical ratings of anxiety (state and trait) and depression were not significantly correlated with presurgical ratings, both were closely related to ratings of locus of control. Belief in powerful others was positively correlated with pre- and postsurgical anxiety and depression. Chance control orientation was related only to presurgical emotional disturbances. It can be concluded that emotional adjustment after heart transplantation is more likely to be predicted by presurgical ratings of locus of control than by presurgical emotional adjustment.

Adaptation, Psychological↗
PubMed1994

Variable participation of 5-HT1-like receptors and 5-HT2 receptors in serotonin-induced contraction of human isolated coronary arteries. 5-HT1-like receptors resemble cloned 5-HT1D beta receptors.

BACKGROUND: Serotonin may contract human large coronary arteries through two 5-hydroxytryptamine (5-HT) receptors, 5-HT1-like and 5-HT2. These 5-HT1-like receptors resemble both cloned 5-HT1D receptor subtypes, 5-HT1D alpha and 5-HT 1D beta. Although these subtypes have similar pharmacology, 5-HT1D beta receptors appear to have lower affinity for ketanserin than 5-HT1D alpha receptors. We assessed the relative participation of 5-HT1-like and 5-HT2 receptors and attempted to identify whether vasoconstrictor 5-HT1-like receptors are 5-HT1D alpha or 5-HT1D beta. METHODS AND RESULTS: Epicardial coronary arteries were dissected from the hearts of 29 patients (including 1 healthy (donor) undergoing heart transplant operation. Endothelium-denuded strips were set up to contract at 37 degrees C. To assess the relative contributions of 5-HT1-like and 5-HT2 receptors, we blocked the latter with ketanserin (0.1 to 1.0 mumol/L) and ketanserin-resistant receptors with methiothepin (0.1 mumol/L). Concentration-effect curves for 5-HT, in the absence and presence of ketanserin, were analyzed by using a model for two receptor subtypes. The fractional contributions of 5-HT1-like and 5-HT2 receptors to the maximum effect of 5-HT, f1 and f2, were estimated in arteries from 28 patients: f1 (0.71 +/- 0.20, mean +/- SD) was significantly larger than f2 (0.29 +/- 0.20) (P < .0001). Using [3H]-serotonin to label transfected and expressed receptors, we verified that ketanserin has lower affinity for 5-HT1D beta (pKi [-log Ki, mol/L] less than 5.0) than for 5-HT1D alpha (pKi = 7.1 +/- 0.1) receptors. A concentration of ketanserin (1 mumol/L) that would occupy more than 90% of 5-HT1D alpha receptors failed to block 5-HT-induced contractions (4 patients). The 5-HT1-like receptor stimulant sumatriptan evoked maximal contractions that matched f1 and was equipotent with 5-HT through 5-HT1-like receptors (8 patients). No systematic influence of disease, atheroma, or therapy on f1 and f2 was detected. CONCLUSIONS: Coronary artery contractile 5-HT1-like receptors resemble cloned 5-HT1D beta receptors and predominate over 5-HT2 receptors in mediating serotonin-evoked contractions. Sumatriptan contracts coronary arteries as a full agonist through 5-HT1-like receptors.

Adult↗
PubMed1994

Relation between myocardial function and expression of sarcoplasmic reticulum Ca(2+)-ATPase in failing and nonfailing human myocardium.

Expression of sarcoplasmic reticulum (SR) Ca(2+)-ATPase was shown to be reduced in failing human myocardium. The functional relevance of this finding, however, is not known. We investigated the relation between myocardial function and protein levels of SR Ca(2+)-ATPase in nonfailing human myocardium (8 muscle strips from 4 hearts) and in myocardium from end-stage failing hearts with dilated (10 muscle strips from 9 hearts) or ischemic (7 muscle strips from 5 hearts) cardiomyopathy. Myocardial function was evaluated by the force-frequency relation in isometrically contracting muscle strip preparations (37 degrees C, 30 to 180 min-1). In nonfailing myocardium, twitch tension rose with increasing rates of stimulation and was 76% higher at 120 min-1 compared with 30 min-1 (P < .02). In failing myocardium, there was no significant increase in average tension at stimulation rates above 30 min-1. At 120 min-1, twitch tension was decreased by 59% (P < .05) in dilated cardiomyopathy and 76% (P < .05) in ischemic cardiomyopathy compared with nonfailing myocardium. Protein levels of SR Ca(2+)-ATPase, normalized per total protein or per myosin, were reduced by 36% (P < .02) or 32% (P < .05), respectively, in failing compared with nonfailing myocardium. SR Ca(2+)-ATPase protein levels were closely related to SR Ca2+ uptake, measured in homogenates from the same hearts (r = .70, n = 16, and P < .005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Transient outward current in human ventricular myocytes of subepicardial and subendocardial origin.

In various mammalian species, shapes of action potentials vary within the cardiac wall because of differences in transient outward current (Ito). A prominent Ito exists in human ventricular myocytes, but cells have not been separated according to their original localization. Human ventricular myocytes were isolated from separated subepicardial and subendocardial tissue, and regional variations in Ito were studied. Ito was larger in subepicardial than subendocardial cells. Current density at +60 mV was 7.9 +/- 0.7 pA/pF (n = 28) in subepicardial cells and 2.3 +/- 0.3 pA/pF (n = 16) in subendocardial cells. When cells from explanted failing and nonfailing donor hearts were compared, Ito was not different in subepicardial cells; however, it was larger in subendocardial cells from nonfailing hearts. The potential of half-maximal activation (V0.5) was more positive in subendocardial cells (+25.6 +/- 3.5 mV, n = 15) than in subepicardial cells (+9.2 +/- 1.8 mV, n = 28). There was no difference in V0.5 between cells from failing and nonfailing hearts. Ito inactivation was similar in all cell types and independent of membrane depolarization (time constant [tau] = approximately 60 milliseconds at 22 degrees C). The potential of half-maximal steady-state inactivation was similar in all cell types. Recovery from inactivation of Ito was fast in subepicardial cells at -100 mV (tau = 24 +/- 4 milliseconds, n = 6), exceeding control values transiently (overshoot), and slow at -40 mV without overshoot (tau = 638 +/- 91 milliseconds, n = 6). In subendocardial cells, Ito recovered at -100 mV with a fast phase (tau = 25 milliseconds) and a slow phase (tau = 328 milliseconds), and recovery was not complete after 6 seconds at -100 mV. In conclusion, regional differences in Ito between subepicardial and subendocardial cells may have clinical implications with respect to rhythmic disturbance during heart failure.

Adolescent↗
PubMed1994

Mechanical ventricular support using pulsatile Abiomed BVS 5000 and centrifugal Biomedicus-pump in postcardiotomy shock.

Since we started using ventricular assist devices (VAD) in July 1987 up to August 1993, 63 of 15,650 (0.4%) patients (pts) who underwent open heart surgery were supported postoperatively by VAD at out institution. Forty-three were male and 20 female, mean age 55.5 years. In 49 pts coronary artery bypass grafting (CABG), in 8 pts valve surgery, in 3 pts combined CABG and valve surgery and in 3 pts corrective procedures for congenital heart disease were performed. Perioperative myocardial infarction was the most frequent indication (73%). In 37 of the 63 pts (58.7%) a centrifugal (Biomedicus pump (group A) was used and in 26 pts (41.3%) a pulsatile Abiomed BVS 5000 (group B). Fourteen of 37 pts (38%) in group A were weaned from the VAD and all of them were discharged. Twenty-three pts were unable to be weaned and 19 of these pts died. The remaining 4 pts were transplanted successfully and subsequently 3 died and 1 was discharged. In all, 15 pts (39%) were long-term survivors. Sixteen of 26 pts (62%) in group B were weaned from VAD and 13 (50%) of them were discharged of whom 3 died. Ten patients were unable to be weaned and 7 of these died. The remaining 3 pts were transplanted successfully. In all, 16 pts (61.5%) were long-term survivors. The shorter the interval between beginning resuscitation and application of VAD the better the outcome. Younger age, VAD installation in OR, support time between 2 and 7 days and Abiomed pump, influence the survival rate positively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[New avenues in therapy of postoperative low output syndrome].

The present definitions of low-output syndrome (LOS) associated with cardiac surgery are based on data obtained via the Swan-Ganz-catheter. However, further important data such as signs of chronic renal insufficiency, arterial vascular disease, and perioperative volume overload have hardly been considered. At the Heart Center NRW, FRG, the Swan-Ganz-Catheter is not used routinely to monitor patients following cardiac surgery. According to our experience, the definition of low-output syndrome includes a wider spectrum of relevant criteria. In addition to the data obtained by means of a central venous catheter the clinical aspect of the patient as well as laboratory analysis should be regarded as well. In 1259 consecutive patients (pts) (914 with coronary surgery and 318 with valve surgery) the incidence and mortality of low-output syndrome were determined. In 49 of the 941 coronary surgery pts (5.2%) a postoperative low-output syndrome occurred. Nine pts (0.95%) died as a result of this complication. According to our therapeutical strategy, the low-output syndrome was treated medically in 28 pts (2.9%); in 14 pts (1.5%) IABP implantation was necessary, and 7 pts needed mechanical circulatory support. Surprisingly, the same incidence of LOS occurred in the valve surgery group of pts as in the coronary group. We saw a low-output syndrome in 17 of the 318 pts (5.3%), with fatal outcome in three pts. In 14 of these pts (4.4%) the LOS was treated medically, while the remaining three pts (0.9%) required diastolic augmentation of the IABP.

Adult↗
PubMed1992

Heart transplantation at the Heart Center North Rhine-Westphalia.

Since 1989, 427 heart transplants were performed at our center, limited only by donor availability, not by moderating donor criteria. Therefore, an increasing number of possible recipients was bridged with mechanical circulatory support systems. Immunosuppression was based on double-drug therapy (CsA, Aza) without steroid maintenance if possible and without mono- or polyclonal antibody prophylaxis. Monitoring adult transplant patients was based on endomyocardial biopsies only during the first 12 months posttransplant. In the pediatric group, only noninvasive diagnostic procedures were performed. Our present 1- and 3-year survival rates for heart transplant patients are 85% and 78%, respectively. We believe that only centers performing approximately 1,000 routine open-heart surgery procedures per year should be allowed to perform heart transplantation, with a minimum of 25 procedures per year (5). Our goal is to start our heart-lung and lung transplant programs in the near future. Our research interests are mainly in the field of postoperative monitoring, induction of immune tolerance, and in establishing a method to determine an individual immunosuppression protocol for each patient (6).

Academic Medical Centers↗
PubMed1992

Improvement of survival rate in patients with cardiogenic shock by using nonpulsatile and pulsatile ventricular assist device.

Between January 1988 and January 1992, 65 patients (pts) had a ventricle assist device (VAD) inserted in our clinic. In 24 pts a VAD was applied because of primarily unsuccessful weaning from cardiopulmonary bypass (Group A). In a further 24 pts (Group B) a VAD was installed for the therapy of refractive cardiogenic shock (CS) after initially successful cardiac surgery (n = 21) and after acute myocardial infarction (n = 3). Twelve pts were bridged to heart transplantation (Group C) and five had a VAD inserted for various other reasons (Group D). In 36 (55.4%) of the total 65 pts a nonpulsatile VAD (Biomedicus 540) was used: 10 in Group A; 20 in B, 3 in C and 3 in D. In 29 pts (44.6%) a pulsatile VAD (Abiomed BVS 5000) was used: 14 in Group A, 4 in B, 9 in C and 2 in D. Weaning rate and long-term survival rates were 50% and 46% respectively in Group A and 38% and 42% in Group B. Seven pts from Group C were transplanted and six are long-term survivors. Two pts (40%) in Group D were discharged from hospital. Major postoperative complications were bleeding (46%), thromboembolism (14%), multiple organ failure (11%), renal failure (11%), arterial embolism (4.6%), sepsis (3%). The results indicate that application of a VAD can be recommended in pts with postcardiotomy CS to allow recovery of cardiac function and in pts with irreversible ventricular damage as bridging to HTX.

Adult↗
PubMed1982

[Bilateral necrosis of the lunate bone. A pathogenic study].

The incidence of clinically and roentgenologically manifest Kienböck disease was checked on the basis of a thorough analysis of 85 patients suffering from the condition. Apart from sex distribution and age at onset, particular importance was attached to certain "constitutional factors". The fact in all bilaterally affected patients the ulnar was smaller than average at the wrist, and the advanced signs of arthrosis were radiologically demonstrated in 81.8% of the patients, once again confirms that certain constitutional factors play a decisive role in the Pathogenesis of Kienböch disease. Their importance for treatment, and also for possible assessments for insurance purpose, is emphasized.

Adolescent↗