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O Bertel

Publications and source records attributed to O Bertel.

At least 55 records · Page 3Linked to original sources
PubMed1997

Acute and short-term effects of the nonpeptide endothelin-1 receptor antagonist bosentan in humans.

In recent years, evidence from various animals experiments has accumulated that emphasizes the role of endothelin-1 in the pathophysiology of several cardiovascular diseases, including congestive heart failure. The recent advent of potent antagonists of this system now allows the assessment of the involvement of endothelin-1 in the maintenance of vascular tone in animals and humans. We report hemodynamic data from two trails in patients with chronic severe congestive heart failure (i.e., reduced left ventricular ejection fraction of < 30%, elevated resting pulmonary capillary wedged pressure > 15 mmHg, and/or reduced cardiac index of 2.5 L/min/m2 or less) who were treated with the mixed endothelin-type A and type B-receptor antagonist bosentan. In the first study, the acute effect of bosentan (300 mg, intravenous) on hemodynamics and neurohormones was investigated. Bosentan was well tolerated and significantly improved impaired hemodynamics due to systemic and venous vasodilation. In the second, trial, bosentan was given orally (0.5 g bid) for 14 days, in addition to conventional triple treatment for congestive heart failure, including digitalis, angiotensin-converting enzyme inhibitors, and diuretics. Cardiac hemodynamics were monitored during the first 24 hours of treatment, and measurements were repeated during the last day of bosentan therapy. Bosentan was well tolerated in these patients as well, and hemodynamic measures were compatible with an additional effect of bosentan after 2 weeks. However, there was a slight increase in heart rate as well. Our result underline the importance of endogenously generated endothelin-1 in congestive heart failure and suggest a potential benefit of endothelin antagonism in such patients. However, long-term studies are needed to establish whether chronic endothelin antagonism has beneficial clinical effects and is capable of improving survival and/or symptoms in severe heart failure patients who remain symptomatic despite standard triple therapy.

Administration, Oral↗
PubMed1996

[Heart surgery in acute heart infarct. Indications and results].

The therapy of acute myocardial infarction has made major advances in the last 10 years. Cardiac surgeons have to adapt their strategies to the more aggressive management of acute myocardial infarction. Only in mechanical complications of acute myocardial infarction is cardiac surgery nowadays the therapy of choice. In cardiac rupture and ventricular septal defect, surgery is the only therapeutic option. In ischemic mitral regurgitation, cardiac surgery is required in the event of concomitant cardiogenic shock and pulmonary edema after intra-aortic balloon pump placement. Coronary artery bypass surgery my be indicated at low risk in patients with unstable angina pectoris when PTCA is not feasible or has failed, or in catheter emergencies.

Acute Disease↗
PubMed1996

Pressure gradients across bileaflet aortic valves by direct measurement and echocardiography.

BACKGROUND: Pressure gradients calculated from echo-cardiography after aortic valve replacement are commonly much higher than would be expected from in vitro measurements. METHODS: The mean, peak-to-peak, and maximal gradients across bileaflet aortic prostheses (St. Jude Medical) were measured invasively in 52 patients at high and low heart rate, cardiac index, and stroke volume. One week after operation the gradients were calculated from a standard transthoracic echocardiogram (delta p = 4v2(2)). In a second study 3 to 12 months later, gradients were calculated using the standard, simplified Bernoulli equation, and with the equation considering subvalvular flow velocities (delta p = 4(v2(2-)v1(2)). Invasive and echocardiographic measurements were matched and compared. RESULTS: Invasively measured mean gradients for 21 to 29-mm valves ranged from 7.4 +/- 4.9 to 4.3 +/- 1.6 mm Hg at systolic flow rates from 11.3 +/- 0.7 to 16.2 +/- 1.8 L.min-1.m-2. Mean echocardiographic gradients were 15.1 +/- 4.5 to 7.5 +/- 2.2 mm Hg (p < 0.001) with the standard method, and 10.5 +/- 1.9 to 5.6 +/- 1.5 mm Hg when considering the subvalvular flow velocity (p < 0.001). CONCLUSIONS: Mean gradients across bileaflet prostheses are generally low, even in small valves and with high systolic flow. The correlation of the invasive in vivo with in vitro gradients is good. Standard echocardiography overestimates gradients across bileaflet heart valves and high gradients are not due to valve dysfunction. Gradients obtained by echocardiography considering the subvalvular flow velocity correlate better to invasively measured and in vitro gradients.

Adult↗
PubMed1996

A comparison of quality-of-life in patients with dual chamber pacemakers and individually programmed atrioventricular delays.

Dual chamber pacemakers are increasingly implanted to achieve optimal hemodynamics by AV synchrony, but the effect of AV delay programming on the patient's quality-of-life has been less well studied. The influence of an individually programmed AV delay between 100 and 250 ms on quality-of-life was investigated in a randomized, double-blind crossover study of 13 patients (69 +/- 10 years of age) with dual chamber pacemakers implanted because of high degree AV block. During radionuclide ventriculography at rest, the "optimal AV delay" with the maximal left ventricular ejection fraction and the "most unfavorable AV delay" with the least ejection fraction were determined. The ejection fraction at rest with the "optimal AV delay" was 51% +/- 10%, and with the "most unfavorable AV delay," 44% +/- 11% (P < 0.0001). The optimal AV delay determined by radionuclide ventriculography correlated well with the optimal AV delay determined by Doppler echocardiography using flow velocity integrals (r = 0.78, P < 0.0016). Each patient was assigned in random order to either AV delay during a 2-week period and then the pacing mode was switched for another 2-week period. At the end of each period, patients were assessed by a functional status questionnaire to assess physical capability and two further questionnaires to quantify cardiovascular symptoms or self-perceived health. There were no differences in the two AV delays regarding the patient's perceived physical capability and specific symptoms. The patient's total judgment was identical to the optimal AV delay (score 36% +/- 19%) and the most unfavorable AV delay (33% +/- 21%). Thus, in patients with a dual chamber pacemaker, an individually programmed AV delay affects left ventricular function at rest, but has no influence on quality-of-life. The determination of the flow velocity integral by Doppler echocardiography is a simple and reliable method to optimize the AV delay if necessary.

Adult↗
PubMed1995

[Heart failure in elderly patients].

The incidence and prevalence of congestive heart failure increase exponentially with advancing age. Congestive heart failure in the elderly is characterized by a multifactorial etiology, a high proportion of accompanying degenerative changes of the cardiovascular system and age-specific problems regarding diagnosis and treatment. The treatment strategy is the same as in younger patients, but the higher incidence of adverse effects and complications demands special awareness. The majority of decompensations leading to hospitalization are precipitated by insufficient compliance in life style change and drug intake.

Adult↗
PubMed1995

Evidence for endothelin-1-mediated vasoconstriction in severe chronic heart failure.

Heart failure is commonly associated with high plasma concentrations of endothelin-1, a powerful vasoconstrictor produced by endothelium. The role of endogenously released endothelin-1 in the maintenance of vascular tone in chronic heart failure was assessed by acute administration of an endothelin receptor antagonist, bosentan. 24 patients with chronic heart failure received randomly and double blind two intravenous infusions of either placebo or bosentan (100 mg followed after 60 min by 200 mg). Systemic haemodynamics and plasma endothelin-1 and big-endothelin-1 concentrations were determined before and repeatedly during the 120 min observation period. Baseline endothelin-1 and big-endothelin-1 concentrations, which were above the normal range in all patients, correlated directly with the extent of pulmonary hypertension, with left and right heart filling pressures, and with pulmonary vascular resistance and inversely with cardiac index. Compared with placebo, bosentan reduced mean arterial pressure by 7.7% (95% CI 7.1-9.7), pulmonary artery pressure by 13.7% (10.5-16.9), right atrial pressure by 18.2% (12.0-24.4), and pulmonary artery wedged pressure by 8.6% (5.3-12.0); it increased cardiac index by 13.6% (9.1-18.2), decreased systemic vascular resistance by 16.5% (13.2-19.8), and decreased pulmonary vascular resistance by 33.2% (22.4-44.0). Heart rate did not change. Plasma endothelin-1 concentrations rose more than twofold from baseline in bosentan recipients while big-endothelin-1 concentrations were unchanged. These findings indicate that, in patients with chronic heart failure who have high circulatory endothelin-1 concentrations, this peptide contributes to maintenance of vascular tone. The acute haemodynamic effects of bosentan suggest that chronic endothelin antagonism could be beneficial in such patients.

Adult↗
PubMed1995

Physical work capacity with rate responsive ventricular pacing (VVIR) versus dual chamber pacing (DDD) in patients with normal and diminished left ventricular function.

To determine the benefit of atrial contribution on work capacity in relation to left ventricular ejection fraction, we studied 17 patients (68 +/- 13 years) with dual chamber pacemakers (DDD) implanted for high degree atrioventricular (AV) block. In random order they were assigned to rate responsive ventricular (VVIR) and to atrial triggered ventricular (VDD) stimulation. Maximum oxygen uptake (max VO2), that correlates best with work capacity, was measured by spiroergometry at a respiratory quotient of 1.1 during treadmill exercise test. Left ventricular ejection fraction at rest was determined by radionuclide ventriculography during VDD-stimulation and an AV delay of 150 ms. There were no differences between these two pacing modes relating heart rate, blood pressure, minute ventilation, exercise duration and maximal work load. In eight patients with an ejection fraction > 50% (60 +/- 10%), but not in nine patients with an ejection fraction < 50% (41 +/- 10%), maximum oxygen uptake was significantly higher (P < 0.01) during atrial triggered ventricular pacing (1440 +/- 533 ml/min) compared with rate responsive ventricular pacing (1328 +/- 536 ml/min). Thus, rate responsive single chamber pacemakers largely enable the same work capacity as dual chamber pacemakers in patients with high degree AV block. Patients with normal left ventricular function may profit most from preserved AV synchrony as shown by the higher maximum oxygen uptake on exercise.

Adult↗
PubMed1995

The internal mammary artery malperfusion syndrome: incidence, treatment and angiographic verification.

Internal mammary artery (IMA) malperfusion syndrome is caused by an acute imbalance between myocardial demand and nutritional support through the mammary artery. In a consecutive series of 2326 isolated myocardial revascularizations-with at least one IMA to the left anterior descending branch (LAD) in 91.3% (2125/2326)-we identified 45 patients (1.9%) with a perioperative course suggesting IMA malperfusion syndrome. Additional saphenous vein graft to the distal segment of the LAD was performed during normothermic ventricular fibrillation in all patients. Hospital mortality was 4.4% (2/45), intra-aortic balloon pumping was required in 15.5% (7/45) and anterior myocardial infarction occurred in 28.8% (13/45). Coronary angiography was performed in all survivors between 3 and 24 months postoperatively. Wide patent IMA graft and patent saphenous vein graft were observed in 56% (24/43), narrowed but patent IMA graft and patent vein graft in 35% (15/43), while patent vein graft and not visualized IMA in 7% (3/43); in one patient with severely diseased peripheral LAD, no flow could be demonstrated in the IMA graft or in the additional vein graft (1/43, 2.4%). No major differences were found between early and late coronary angiography in these patients. Additional vein graft to distal LAD is the treatment of choice in acute IMA malperfusion syndrome. Despite patent vein graft with superior blood flow, early and late postoperative IMA flow to LAD is maintained in the majority of patients.

Adult↗
PubMed1995

Influence of coronary artery bypass grafting on ventricular late potentials as a predictive factor for ventricular arrhythmias during short- and long-term follow-up.

UNLABELLED: Ventricular late potentials have been identified as a prognostic factor in the prediction of ventricular arrhythmias in patients after myocardial infarction. In this prospective study the possible impact of late potentials on the prediction of ventricular arrhythmias in the short- and long-term follow-up after coronary artery bypass grafting was evaluated. In 188 patients (165 men, 23 women, age 57 +/- 8 years) with chronic coronary heart disease 48 (26%) had late potentials before bypass grafting; after the procedure this was reduced to 39 (21%) (ns). In 16 (33%) of the 48 patients with late potentials before bypass grafting, late potentials were no longer present in the short-term follow-up (9 +/- 6 days). Conversely, seven (5%) of the 140 patients without late potentials before bypass grafting had late potentials in the short-term follow-up after grafting. Nine (19%) of the 48 patients with late potentials before bypass grafting had ventricular arrhythmias in the peri-operative phase, which had to be treated with antiarrhythmic agents. In contrast, only three (2%) of the 140 patients without late potentials before bypass grafting had to be treated for ventricular arrhythmias (P < 0.001). In the long-term follow-up of 29 +/- 3 months, there were no events in the group of 149 patients without late potentials after grafting. In the 39 patients with late potentials after grafting, there were two (5%) events (two patients with arrhythmic syncope). CONCLUSIONS: (1) Patients with late potentials before bypass grafting have a markedly higher risk of developing serious ventricular arrhythmias in the peri-operative period than patients without late potentials. (2) Patients without late potentials have a very low risk of developing serious ventricular arrhythmias in the peri-operative period. (3) During long-term follow-up there was only a low probability of developing symptomatic ventricular arrhythmias in patients with or without late potentials.

Arrhythmias, Cardiac↗
PubMed1994

[Cardiac interventions in Switzerland 1992. PTCA and Fibrinolysis Work Group of the Swiss Cardiology Association].

In 1992, 14,348 coronary angiographies were performed in Switzerland (2110 per 1 million population). This represents a 10% (+1332) increase over the previous year. About 50% were performed at university hospitals. Over the past 5 years, interventions for myocardial revascularization (coronary angioplasty [PTCA] and coronary artery bypass grafting [CABG] have increased constantly and nearly linearly. The increase from 1991 to 1992 was 8% (510) (PTCA: +18% [+469]; CABG: +1% [+41]). The PTCA/CABG ratio amounted to 0.9/1 for all Swiss hospitals. At university hospitals, angioplasty was performed more frequently than bypass grafting (PTCA/CABG 1.3/1) in contrast to the private hospitals (PTCA/CABG 0.4/1). More than a third of all revascularizations were performed in private hospitals. The increase in angioplasty is a consequence of an increase in coronary angiography and not of an increase in the percentage of multivessel PTCAs. This indicates that coronary artery disease is being diagnosed and treated more actively without necessarily adopting more aggressive PTCA indications. There was an obvious difference in morbidity and mortality rates, both after PTCA and CABG, between some private and public hospitals. The fact that public hospitals are obliged to accept high risk emergency cases is to their disadvantage. So is their more complete data collection, which reveals the actual incidence of complications more accurately.

Angioplasty, Balloon, Coronary↗
PubMed1994

Importance of an individually programmed atrioventricular delay at rest and on work capacity in patients with dual chamber pacemakers.

Despite higher costs, expenditure, and the necessity of repeatedly reprogramming of dual chamber pacemakers, they are increasingly implanted to achieve an optimal work capacity. The influence of an individually programmed atrioventricular (AV) delay between 100-250 msec on physical work capacity in 12 patients (68 +/- 16 years) with dual chamber pacemakers implanted for high degree AV block was studied. During radionuclide ventriculography at rest the "optimal AV delay" with the maximal achieved left ventricular ejection fraction and the "most unfavorable AV delay" with the least achieved ejection fraction were determined. The ejection fraction at rest with the "optimal AV delay" was 51 +/- 14% and with the "most unfavorable AV delay" 45 +/- 15% (P < 0.001). In random order each patient was assigned to either AV delay and a spiroergometry was performed to determine maximum oxygen uptake (max VO2), which correlates best with work capacity, at a respiratory quotient of 1.1. The results show neither a difference in maximum oxygen uptake (1,262 +/- 446 mL/min with the optimal AV delay, 1,248 +/- 400 mL/min with the most unfavorable AV delay, respectively) nor in heart rate, blood pressure, exercise duration, maximal workload, and minute ventilation. Thus, an individually programmed AV delay affects left ventricular ejection fraction at rest. In contrast, an individually programmed AV delay has no influence on physical work capacity in patients with a dual chamber pacemaker.

Adult↗
PubMed1993

[Inadequate treatment compliance, patient information and drug prescription as causes for emergency hospitalization of patients with chronic heart failure].

UNLABELLED: Causes of decompensation of treated chronic congestive heart failure in patients referred for emergency hospitalization were examined prospectively. 111 consecutive patients (76 +/- 11 years) were interviewed and their records examined on admission. The diagnosed underlying diseases were coronary artery disease (80%), hypertensive heart disease (40%), valvular heart disease (11%), and idiopathic dilated (7%) and alcoholic (5%) cardiomyopathy. The grounds for decompensation of chronic congestive heart failure were: insufficient compliance 47% (n = 52, irregular or not intake of medication [25%], salt [9%] or fluid [7%] excess, stopping medication because of side effects [6%]), uncontrolled hypertension (27%), insufficient diuretic therapy in spite of progressive symptoms (23%), treatment with negative inotropic drugs (21%), acute rhythm disturbances (14%), acute myocardial infarction or unstable angina pectoris (14%), infections (6%). 80% of the patients were treated with diuretics, 34% with digoxin, 31% with ACE-inhibitors. Insufficient basic knowledge about the disease (regular weighing, diet, behavior if symptoms worsen) was found in 78% of patients, complete lack of knowledge concerning the prescribed drugs in 29%. Only 44% were regularly followed by their physicians, 53% had either no regular follow-ups or they were set at too long intervals. CONCLUSIONS: In the majority of patients, one or more avoidable causes leading to decompensation of chronic congestive heart failure can be identified. The main potential for intervention aiming at a reduction of the hospitalization frequency lies in improving patient compliance and state of the art medication by the primary care physician. Equally unsatisfactory is the low frequency of follow-up checks to reassess and renew drug therapy.

Aged↗
PubMed1993

Phosphorylation of serine 2843 in ryanodine receptor-calcium release channel of skeletal muscle by cAMP-, cGMP- and CaM-dependent protein kinase.

The aim of the present study was to determine the phosphorylation of the purified ryanodine receptor-calcium release channel (RyR) of rabbit skeletal muscle sarcoplasmic reticulum by the cAMP-dependent protein kinase (PK-A), cGMP-dependent protein kinase (PK-G) and Ca(2+)-, CaM-dependent protein kinase (PK-CaM) and the localization of phosphorylation sites. Phosphorylation was highest with PK-A (about 0.9 mol phosphate/mol receptor subunit), between one-half to two-thirds with PK-G and between one-third and more than two-thirds with PK-CaM. Phosphoamino acid analysis revealed solely labeled phosphoserine with PK-A and PK-G and phosphoserine and phosphothreonine with PK-CaM. Reverse-phase high-performance liquid chromatography (HPLC) of cyanogen bromide/trypsin digests of the phosphorylated RyR (purified by gel permeation HPLC) and two-dimensional peptide maps revealed one major phosphopeptide by PK-A and PK-G phosphorylation and several labeled peaks by PK-CaM phosphorylation. Automated Edman sequence analysis of the major phosphopeptide obtained from PK-A and PK-G phosphorylation and one phosphopeptide obtained from PK-CaM phosphorylation yielded the sequence KISQTAQTYDPR (residues 2841-2852) with serine 2843 as phosphorylation site (corresponding to the consensus sequence RKIS), demonstrating that all three protein kinases phosphorylate the same serine residue in the center of the receptor subunit, a region proposed to contain the modulator binding sites of the calcium release channel.

Amino Acid Sequence↗
PubMed1993

[Epidemiologic aspects of heart failure: incidence, causes and follow-up].

Congestive heart failure can develop as a complication of virtually all forms of heart diseases. Depending on diagnostic criteria, the figures for prevalence and incidence differ markedly. The frequency of congestive heart failure increases with age and doubles in each life decade. In the United States the prevalence of 1% and for Great Britain 0.4% respectively have been calculated. In the highest age groups up to 90 new cases/1000 population per year can be observed. As a contribution to decreasing mortality of acute myocardial infarction and better treatment of high blood pressure as well as congestive heart failure the number of patients in heart failure have increased substantially. In contrast to the Framingham Study, nowadays coronary artery disease is the most prevalent etiology of congestive heart failure followed by hypertensive heart disease. In younger patient groups with advanced heart failure, like heart transplant recipients, cardiomyopathies are the main etiologic factor. Heart failure is the leading factor for emergency admissions to hospital in adult internal medicine. The main reasons for decompensation are acute ischemic syndromes for acute congestive heart failure and compliance problems for chronic congestive heart failure. The natural history of congestive heart failure is characterized by a marked progression, increasing with the severity of heart failure. In parallel, mortality increases, too. A variety of clinical, hemodynamic neurohumoral and electrophysiologic factors have been described as independent factors predicting prognosis. 30 to 50% of heart failure patients die a sudden death as compared with progressive pump failure or infectious complications in the others.

Cause of Death↗
PubMed1992

[Heart contusions: pathological findings and clinical course].

After blunt chest trauma, myocardial contusion is frequently suspected, but diagnostic criteria are difficult to define and commonly accepted recommendations for duration and form of patient monitoring are lacking. We therefore conducted a retrospective review of the hospital records of 50 consecutively hospitalized patients with the diagnosis of myocardial contusion after blunt chest trauma, and analyzed the pathological laboratory, ECG and echocardiography findings as well as the associated injuries and cardiac-related complications. The average injury severity score was 25 +/- 8. Initially 98% of the patients were hemodynamically stable. In 90% there were abnormal enzyme levels consistent with myocardial injury. Typically, the maximum level of CPK-MB, LDH and CPK-MB/CPK (MB-fraction) was found initially and these values declined rapidly. The MB fraction normalized within 8 hours. In 32% of the patients there were the following ECG changes consistent with myocardial contusion transient: ventricular tachycardia (12%), ST/T changes (12%), complete right bundle branch block (10%), atrial fibrillation (4%), first degree AV block (2%). The episodes of ventricular tachycardia were registered within the first 24 hours; in 5 of these 6 patients the admission ECG was normal. An echocardiography was done in 64% of the patients and in 37% showed either a pericardial effusion, regional wall motion abnormalities, a pneumopericardium or an intramyocardial hematoma in the free wall of the right ventricle. One patient died of multiorgan failure during this hospitalization. There were no sudden cardiac deaths. The diagnosis of myocardial contusion is vital in unstable patients but also very important in hemodynamically stable patients, despite its low morbidity. The minimum program we recommend for diagnosis and monitoring should include enzyme levels (CPK, CPK-MB) and ECG controls. Echocardiography may be necessary as well. If during the initial compulsory 24 hour monitoring of ECG and hemodynamics no complications occur, further monitoring is not necessary.

Adolescent↗
PubMed1992

[Spontaneous left atrial echo contrast in trans-esophageal echocardiography].

Left atrial spontaneous contrasts (LASC) are found almost exclusively with transesophageal echocardiography (TEE), usually in patients with mitral stenosis or mitral prosthetic valves. The prevalence of LASC was examined in 143 consecutive patients undergoing TEE and transthoracic echocardiography (TEE). LASC of variable intensity were observed in 31 patients (22%) with TEE, in contrast to none with TTE. There was a significant correlation between the presence of LASC and atrial fibrillation (p less than 0.001), left atrial dilatation (p less than 0.005) and presence of mitral valve prosthesis or mitral stenosis (p less than 0.02). In 48% of patients with LASC the mitral valve was entirely normal. Multivariance analysis showed atrial fibrillation and left atrial dilatation to be independent predictors for the presence of LASC. There were significantly more ischemic strokes in patients with LASC (35% vs 12% in patients without LASC). LASC are a frequent observation with TEE. As sensitivity of the echocardiography instruments steadily improves, LASC are also found in increasing numbers of patients with minimal structural change of the heart. LASC may indicate the presence of microthrombi and thus be involved in the pathogenesis of thromboembolic complications; their clinical relevance and prognostic significance needs to be further investigated.

Adult↗