PubMed Health⌕ Search

Biomedical subjects

D Burckhardt

Publications and source records attributed to D Burckhardt.

At least 19 recordsLinked to original sources
PubMed1998

[Incidence of thromboembolism after heart valve replacement: modifying factors].

The most important factors influencing thromboembolic rates after valve replacement are: 1) Cardiogenic factors such as left ventricular function, left atrial size and atrial rhythm. 2) Prosthesis-related factors such as type of prosthesis, position of prosthesis, and time after implantation. 3) Patient-related factors such as quality of anticoagulation and gender. 4) Conditions with hypercoagulability.

Cross-Sectional Studies↗
PubMed1997

[Survived sudden cardiac death in aortic stenosis and Wolff-Parkinson-White syndrome: Differential diagnosis and therapy].

Based on a case of a 72 year old woman with hemodynamically non-significant aortic stenosis. WPW-syndrome and out-of-hospital cardiac arrest, the diagnostic assessment and differential diagnosis of potentially fatal arrhythmias are discussed. In particular, the incidence of supraventricular and ventricular arrhythmias in patients with WPW-syndrome, their prognostic impact and therapeutic options are outlined.

Aged↗
PubMed1996

[Cerebral ischemic events: when and how to look for a cardiac embolism source?].

In industrialized countries, cerebral ischemic events rank third among the most frequent causes of death. In survivors, long-term disability may result. The diagnosis and therapy of preventable causes is therefore a major task. Echocardiography has proven to be most helpful in the search for cardioembolic sources, and the transesophageal approach (TEE) is superior to the transthoracic (TTE) in this specific indication. In patients in whom a cardioembolic source can be identified by clinical examination, 12-lead surface ECG or chest X-ray, an additional echocardiographic examination is not necessary. Patients under 50 with cerebral ischemic events should undergo TEE. In patients over 70 with a contraindication for long-term anticoagulant therapy, TEE has no therapeutic consequences and should therefore not be performed. In patients aged between 50 and 70 the diagnostic procedure of choice must be considered in each individual patient. It should be kept in mind that a more aggressive approach using TEE, from which therapeutic conclusions are drawn, has not clearly been shown to improve the prognosis of patients with cerebral ischemic events.

Age Factors↗
PubMed1996

Benefits and limitations of rate adaptive pacing under laboratory and daily life conditions in patients with minute ventilation single chamber pacemakers.

Rate adaptive pacing has been shown to improve hemodynamic performance and exercise tolerance during acute testing. However, there remain concerns about its benefit in daily life and possible complications incurred by unnecessary pacing. This double-blind crossover study compared the benefit of rate adaptive (SSIR) versus fixed rate (SSI) pacing under laboratory and daily life conditions in 20 rate incompetent patients with minute ventilation single chamber pacemakers (META II). The heart rate (HR) response during three different exercise tests (treadmill, bicycle ergometry, walking test) was correlated with the Holter findings during daily life in either pacing mode. The maximal HR was significantly higher in the SSIR-mode compared to the SSI-mode, both during laboratory testing (treadmill: 123 +/- 15 vs 93 +/- 29 beats/min; ergometry: 118 +/- 15 vs 89 +/- 27 beats/min; walking test: 127 +/- 9 vs 95 +/- 26 beats/min, all P values < 0.01) as well as during daily life (Holter: 126 +/- 13 vs 103 +/- 24 beats/min, P < 0.01). On Holter, the average HR (71 +/- 14 vs 71 +/- 8 beats/min) and the percentage of paced rhythm (54% vs 62%, SSI- vs SSIR-mode, P = NS) were not different in either mode. However, despite a 30% rate gain in the SSIR-mode, the exercise capacity remained unchanged, and only 38% of patients preferred the SSIR-mode. Minute ventilation pacemakers provide a physiological rate response to exercise. Irrespective of the protocol used, the findings of laboratory testing are comparable to those during daily life. However, patient selection for rate adaptive single chamber pacing should be made with caution, since the objective benefit of restoring normal chronotropy may subjectively be negligible for most patients.

Aged↗
PubMed1995

Antibiotic prophylaxis for infective endocarditis from an international group of experts towards a European consensus. Group of Experts of the International Society for Chemotherapy.

Antibiotic prophylaxis for infective endocarditis is recommended for cardiac patients at risk who undergo an at-risk procedure. Efforts should focus on patients with the highest risk, i.e., those with a prosthetic valve undergoing a dental procedure. Amoxicillin is the main recommendation in patients who are not allergic to penicillin. In patients allergic to penicillin clindamycin orally or vancomycin intravenously are proposed. Aminoglycosides are added for gastrointestinal or urological procedures.

Anti-Bacterial Agents↗
PubMed1995

[Recommendations for prevention of thromboembolism in heart valve diseases. Working Group on Valvular Heart Disease, European Society of Cardiology].

Thromboembolic events are still a major cause of morbidity and mortality in patients with native valvular heart disease and in patients with prosthetic heart valves. Although the introduction of oral anticoagulation reduced this risk, thromboembolism and anticoagulation-related hemorrhages still represent significant problems in the management of these patients. In this article the guidelines developed by the Working Group on Valvular Heart Disease of the European Society of Cardiology for the management of antithrombotic therapy in heart valve disease are thoroughly discussed. The indication for and intensity of anticoagulation in various clinical situations, the concept of risk factor-adjusted intensity of anticoagulation, and the concept of control of oral anticoagulation with the International Normalized Ratio are presented.

Administration, Oral↗
PubMed1994

[Transesophageal echocardiography in the diagnosis of endocarditis].

Transesophageal echocardiography is a new diagnostic method for visualization of retrocardial structures and heart valves with high resolution. This retrospective analysis describes the use of and the findings by transesophageal echocardiography in patients suspected to suffer from endocarditis studied in three hospitals. 50 patients were studied; the diagnosis was confirmed in 64%, whereas 36% (controls) had other findings. The leading initial symptoms were fever and valvular incompetence. Laboratory parameters were altered in both groups with equal frequency. One or more diagnostic features were detected by transesophageal echocardiography in 88% of patients with endocarditis: vegetations (approximately with equal frequency on the mitral and the aortic, rarely on the tricuspid valve) were detected in 75% and/or abscesses in 22% of them. Only one patient in the control group with a history of endocarditis had vegetation-like structures on the aortic valve. Transesophageal echocardiography was on the average performed on the seventh day of hospitalization. With the exception of one female patient, all had been treated with antibiotics. Valve replacement was recommended in 65% of the patients with endocarditis and was in 59% also performed (single or double valve replacement), most frequently because of aortic or mitral regurgitation. The other patients were treated with antibiotics. Transesophageal echocardiography thus detects vegetations and abscesses in endocarditis frequently, findings that influence treatment in a significant manner.

Adult↗
PubMed1994

[Subjective tolerance to transesophageal echocardiography].

Transesophageal echocardiography (TEE) is a new semi-invasive diagnostic tool in cardiology. We studied tolerance of TEE. 95 out of 121 consecutive patients were interviewed using a detailed, structured questionnaire (42 questions). Most patients (97%) received midazolam prior to TEE. TEE was tolerated well by 89% (n = 84) of the patients. Patients receiving a higher dose of midazolam (> 0.04 mg/kg bodyweight) tolerated TEE better than those in the lower-dose group (p < 0.0005), but they experienced side effects more often (p < 0.05) and did not tolerate fatigue as well (p < 0.0005). TEE was tolerated less well by younger patients (age < or = 45 years); they experienced more often local irritation than older patients due to the endoscope (52% versus 20% in older patients, p < 0.005) and complained more often about dysphagia (70% versus 24%) and sore throat (60% versus 19%) (p < 0.0005) after TEE. Patients < or = 45 years reported more side effects by midazolam than older patients, such as palpitations (30% versus 2%), hiccups (17% versus 0%), poor concentration (20% versus 3%), nausea (13% versus 2%), ataxia (17% versus 3%) or fatigue (88% versus 59%) (p < 0.05 to 0.0005). Females were more often afraid of TEE (53%) and the endoscope (56%) than males (35% and 23%, p < 0.08 and p < 0.002) and also disliked the endoscope more often (42%) than men (19%, p < 0.03). Some women complained about headaches after TEE (10%), whereas men did not (p < 0.05). Thus, TEE, after premedication with midazolam, is subjectively well tolerated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Transesophageal echocardiography: indications and findings. Experiences from 3 centers].

The introduction of transoesophageal echocardiography has greatly enhanced the noninvasive diagnostic possibilities in cardiology. This multicentre report analyses the findings in different indications as well as the rate of complications in 335 consecutive patients on whom transoesophageal echocardiography was performed. The most frequent indication was the search for a cardiac source of embolism (36%). Compared to patients with other indications, thrombi in the left atrial appendage, atrial septal aneurysms and protruding aortic atheromas were significantly more frequent in this group. Transoesophageal echocardiography was performed in 20% for the diagnosis of suspected endocarditis and vegetations and/or paravalvular abscesses could be demonstrated in 46% of these patients. Other important indications included the assessment of mitral valve disease, congenital heart disease, valve prosthesis dysfunction and aortic dissection. Clinically relevant complications occurred in 1.8% and were spontaneously reversible in all cases. Transoesophageal echocardiography is an extremely valuable and safe diagnostic tool in cardiology.

Adolescent↗
PubMed1994

Aortic valve replacement in elderly patients with aortic stenosis.

OBJECTIVE: To assess the risk of aortic valve replacement and long-term follow-up in elderly patients with dominant aortic stenosis. DESIGN: Retrospective analysis of patients who had aortic valve replacement over a 10 year period and were routinely seen in an outpatient clinic. SETTING: University hospital. PATIENTS: 93 patients aged > or = 60 and 47 patients > or = 70 years with symptomatic aortic stenosis undergoing aortic valve replacement. MAIN OUTCOME MEASURES: Early and late mortality in different age groups. Influence of preoperative signs and symptoms on overall outcome. RESULTS: The proportion of patients older than 70 years increased from 11% in 1978 to 54% in 1986. Perioperative mortality was 3.6% and mortality after 2 and 5 years was 9% and 13% respectively. Survival was similar (85% and 83%, respectively) in patients aged 60-69 years (group 1, n = 93, mean age 64.5 (2.7) and patients aged > or = 70 years (group 2, n = 47, mean age 72.6 (2.5)). Additional coronary artery disease and coronary bypass grafting did not significantly affect survival. The cardiothoracic ratio was inversely related to survival (Cox regression, p < 0.05). Preoperative symptoms (syncope, angina pectoris, and dyspnoea) were similar in both patient groups. After a mean (SD) follow up of 51 (33) months 96% of surviving patients were in NYHA functional class I or II with no difference between the two age groups. Similarly, the cardiothoracic ratio and Sokolow index decreased to near normal values in both age groups. CONCLUSION: The risk of aortic valve replacement in patients with dominant aortic stenosis is low and not significantly influenced by age. Therefore replacement may be performed without increased risk in elderly patients and with a good long-term outcome.

Age Factors↗
PubMed1994

Diminished vascular response to inhibition of endothelium-derived nitric oxide and enhanced vasoconstriction to exogenously administered endothelin-1 in clinically healthy smokers.

BACKGROUND: Smoking is a major risk factor for the development of atherosclerosis. Because endothelial dysfunction may be a marker for future atherosclerosis, we investigated the effects of smoking on endothelium-dependent control of vascular tone. METHODS AND RESULTS: The effects of brachial arterial infusions of NG-monomethyl-L-arginine (L-NMMA), a nitric oxide synthesis inhibitor; sodium nitroprusside; endothelin-1; and norepinephrine on forearm blood flow (strain-gauge plethysmography) were compared in 29 long-term smokers and 16 nonsmokers. The acute effects of smoking on systemic hemodynamics, plasma catecholamines, and forearm vascular responses to these compounds were investigated in smokers only. Smokers did not differ from nonsmokers (n = 16) regarding the vascular effects of sodium nitroprusside (n = 13) or vasoconstriction due to norepinephrine and endothelin-1 (n = 16). Low-dose endothelin-1-induced vasodilation, believed to reflect endothelial prostacyclin or nitric oxide release, was absent in smokers (n = 16), and their increase of forearm vascular resistance (FVR) after L-NMMA (n = 13) was impaired (35.6 +/- 27.9% versus 118.8 +/- 43.2%, P < .001). Short-term smoking (n = 11) increased blood pressure, heart rate, and plasma epinephrine concentrations (P < .05 or less); enhanced endothelin-1-induced vasoconstriction (delta FVR, 457 +/- 192% versus 254 +/- 143%, P < .01); and decreased norepinephrine-induced vasoconstriction (P < .05), but had no effect on the other interventions. CONCLUSIONS: Long-term smoking is associated with a diminished nitric oxide-dependent component of basal vascular tone and an impaired endothelium-dependent vasodilator response to low-dose endothelin-1 and short-term smoking enhances endothelin-1-induced vasoconstriction. Impaired endothelial control of vascular tone might reflect impairment of normal antiatherosclerotic endothelial functions in smokers, but the relevance of smoking-induced enhancement of endothelin-1 vasoconstriction remains to be determined.

Adult↗
PubMed1994

High intensity transcranial Doppler signals (hits) after prosthetic valve implantation.

High intensity transcranial Doppler signals (HITS), assumed to be caused by microemboli, have been reported to occur in many patients with mechanical heart valve prostheses. The aim of our study was to quantify these phenomena and to find possible differences. Furthermore, parameters which might influence the prevalence of HITS were investigated. Monitoring of both middle cerebral artery frequency shift spectra was carried out for 10 minutes in 100 patients having an aortic (n = 64) and (n = 5)/or (n = 31) mitral mechanical heart valve prosthesis. The spectra were off-line screened for HITS by ear. The findings were correlated with the degree of anticoagulation and with the time period since implantation. To examine if platelet aggregates would be the underlying cause, another HITS count was done for 10 minutes prior to and 40 minutes after i.v. injection of 250 mg aspirin (ASA) as well as after four days of 100 mg/day ASA orally in a group of seven patients. Prior to surgery, HITS were present in only one patient. Postoperatively, HITS were detected in 54 of 100 patients. There was no significant difference between left and right sides, no correlation with anticoagulation, and only a borderline correlation with the time interval since implantation. Sixty-six percent of the 50 patients monitored within the first three postoperative weeks had HITS as compared to only 42% in 50 subjects who were examined three months or later after surgery (p < 0.05). With regard to the number of HITS an inverse behaviour was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1993

[Long-term effect of amiodarone therapy following myocardial infarct in patients with complex ventricular arrhythmias].

In the BASIS study, an improvement in 1 year survival of patients with asymptomatic complex ventricular arrhythmias with low-dose amiodarone was shown in comparison with an untreated control group. To assess whether this beneficial effect would last for a longer follow-up despite discontinuation of amiodarone therapy after one year, we assessed long-term survival and mode of death in the 91 survivors of the first year in the amiodarone treatment group and the 99 survivors in the control group by phone calls to private physicians, patients and hospitals. During a median follow-up of 72 (55-125) months, 184/193 patients (95%) could be reached. Causes of death during the follow-up were sudden (6 vs 14), non-sudden cardiac (8 vs 9), non cardiac (5 vs 9) and unknown (7 vs 6) in patients initially treated with amiodarone versus the control group respectively. The probability of death after 84 months was 30% in the amiodarone group and 45% in the control group, and was significantly lower in amiodarone treated patients with respect to all deaths (p = 0.024) as well as cardiac deaths (p = 0.027). This mortality reduction was only due to amiodarone treatment during the first year after the index infarction, whereas the survival curves did not differ significantly during the late follow-up. Thus, the risk of cardiac death is low after the first year after myocardial infarction and may not justify continued antiarrhythmic therapy in patients with initially complex asymptomatic ventricular arrhythmias.

Aged↗
PubMed1993

Silent myocardial ischemia in glaucoma patients.

The pathophysiological mechanism involved in normal-tension glaucoma is still not fully understood. Besides intraocular pressure, vascular and rheological factors have been described. In the present study, the prevalence of silent myocardial ischemia in patients of the same age with normal-tension glaucoma, primary open-angle glaucoma and cataract was compared. Our findings indicate that in all three groups ischemic episodes occurred more frequently than described in normal people. The most striking observation, however, was the fact that in normal-tension glaucoma the frequency was twice that of the other two groups.

Electrocardiography↗
PubMed1993

Long-term benefit of 1-year amiodarone treatment for persistent complex ventricular arrhythmias after myocardial infarction.

BACKGROUND: In the Basel Antiarrhythmic Study of Infarct Survival trial, low-dose amiodarone improved 1-year survival in patients with asymptomatic complex ventricular arrhythmias persisting 2 weeks after myocardial infarction. To assess whether this beneficial effect persisted despite discontinuation of amiodarone after 1 year, the long-term outcomes of all patients of the amiodarone-treated group (initially n = 98) and those of the control group (n = 114) were assessed. METHODS AND RESULTS: After a mean follow-up of 72 (55-125) months, information on 96% of patients (203 of 212) was obtained regarding survival or cause of death. The probability of death after 84 months according to actuarial life-table analysis (Kaplan-Meier) was 30% for the amiodarone-treated patients and 45% for control patients. For the total follow-up, mortality remained significantly lower in the amiodarone group versus the control group regarding all deaths (p = 0.03) as well as cardiac death (p = 0.047). This mortality reduction was entirely due to the first-year amiodarone effect, since there was no significant mortality difference between groups when considering survival after discontinuation of amiodarone only. CONCLUSIONS: These data suggest that the beneficial effect of amiodarone on survival in this high-risk group of patients persists for several years. In addition, the results stress the importance of early treatment after myocardial infarction, whereas the rate of sudden death and all cardiac death is low (1.6% and 4.1% per year, respectively) during late follow-up and therefore may not warrant further therapy.

Amiodarone↗
PubMed1993

Progression of aortic stenosis. Role of age and concomitant coronary artery disease.

To determine the spontaneous progression of valvular aortic stenosis and to delineate clinical factors related to progression, a longitudinal study, including 49 patients (aged 16 to 81 years), was performed. All patients had auscultatory findings of aortic stenosis and multiple Doppler echocardiograms separated by at least 11 months. Rapid progression of aortic stenosis was defined as an increase of maximal instantaneous pressure gradient by > or = 10 mm Hg per year. During a mean follow-up period of 32 months (11 to 66 months), maximal pressure gradient rose from 38 +/- 15 to 60 +/- 20 mm Hg in the entire study population, resulting in a median increase of 7.2 mm Hg per year. In 21 patients (43 percent), an increase of > or = 10 mm Hg per year was found; in this subgroup with rapid progression, patients were older (64 vs 53 years, p < 0.01) and coronary artery disease was more prevalent (38 percent vs 7 percent, p = 0.01). We conclude that nearly half the patients with initially mild to moderate valvular aortic stenosis reveal a progression of > or = 10 mm Hg per year.

Adolescent↗
PubMed1993

Optimal timing of surgery for chronic mitral or aortic regurgitation.

Symptoms tend to develop late in the course of both chronic mitral and chronic aortic regurgitation, and when the regurgitation is stable patients may enjoy many years of full activity free from disability. In the absence of complicating atrial fibrillation or coronary artery disease the onset of dyspnoe and fatigue usually indicate myocardial failure and possibly a lost opportunity for a low risk operation and long term benefit. Valve replacement for aortic regurgitation is a good operation which reduces left ventricular work. However, mitral valve replacement is unphysiologic and not surprisingly, the operative mortality and long term results are worse with an excess of deaths caused by left ventricular failure. While the need for operation is obvious when patients already have symptoms or when valvar regurgitation is increasing, timing is far more difficult for patients with severe, chronic, stable regurgitation who still enjoy a high quality of life. It is even more difficult in mitral regurgitation because the stakes are higher with a higher operative risk, but suitability for mitral valve reconstruction justifies earlier operation and therefore makes it mandatory for cardiologists to identify such patients.

Aortic Valve Insufficiency↗