Search PubMed⌕ Search

Biomedical subjects

D Burckhardt

Publications and source records attributed to D Burckhardt.

At least 55 records · Page 3Linked to original sources
PubMed1990

Prevention of aortocoronary vein bypass graft occlusion: which antithrombotic treatment and for how long?

The effects of 50 mg aspirin combined with 400 mg dipyridamole were compared with those of standard anticoagulant therapy, in the prevention of aortocoronary vein bypass graft occlusion. Early graft occlusion in 249 patients, with 749 distal vein graft anastomoses, were angiographically assessed 11.5 +/- 2 days after surgery and were almost equal in both treatment groups. In half of the patients in each group, active treatment was replaced by placebo after 3 months. Repeat angiography after 1 year (360 +/- 24 days) showed that more new late graft occlusions occurred in patients with only 3 months active medication (either regimen). The incidence of major complications was significantly higher in patients treated with anticoagulants, with minor side-effects more common in the antiplatelet group. Thus, this antiplatelet drug regimen was as effective as standard anticoagulant therapy in the prevention of early and late bypass graft occlusion, but carried a significantly lower risk of severe complications. In addition, as replacement of active treatment by placebo after 3 months resulted in significantly more graft occlusions, antithrombotic treatment should be continued for at least one year after coronary artery bypass graft surgery.

Adult↗
PubMed1990

Long-term follow-up of patients with silent ischemia during exercise radionuclide angiography.

A retrospective 5 year follow-up study was performed in 140 patients with unequivocal ischemia during exercise radionuclide angiography (greater than or equal to 10% decrease in left ventricular ejection fraction or greater than or equal to 5% decrease in ejection fraction together with a distinct regional wall motion abnormality). In 84 patients (60%), ischemia during radionuclide angiography was silent (silent ischemia group), whereas 56 patients experienced angina during the test (symptomatic group). Work load and antianginal medication were similar in both groups. Critical cardiac events (unstable angina, myocardial infarction, cardiac death) occurred in 27% of patients in the silent ischemia group and 16% of those in the symptomatic group (p = NS); however, myocardial infarction or death was more frequent in patients with silent ischemia (22% versus 9%; p less than 0.05). If there was additional exercise-induced ST segment depression, the rate of critical events was further increased (p less than 0.05). The difference in critical cardiac events seemed to be influenced by the higher incidence of revascularization procedures in symptomatic patients, whereas medical therapy had no similar effect. Thus, these findings suggest that patients with documented severe ischemia should undergo left heart catheterization and revascularization irrespective of symptoms to improve their prognosis.

Adult↗
PubMed1990

Effect of antiarrhythmic therapy on mortality in survivors of myocardial infarction with asymptomatic complex ventricular arrhythmias: Basel Antiarrhythmic Study of Infarct Survival (BASIS)

In view of the high risk of sudden cardiac death and the prognostic importance of complex ventricular ectopic activity, the effects of prophylactic antiarrhythmic treatment were investigated prospectively in patients with persisting asymptomatic complex arrhythmias after myocardial infarction. End points were total mortality and arrhythmic events (sudden death, sustained ventricular tachycardia and ventricular fibrillation). Of 1,220 consecutively screened survivors of myocardial infarction, 312 had Lown class 3 or 4b arrhythmia on 24 h electrocardiographic recordings before hospital discharge and consented to the study. They were randomized to individualized antiarrhythmic treatment (Group 1, n = 100), treatment with low dose amiodarone, 200 mg/day (Group 2, n = 98) or no antiarrhythmic therapy (Group 3 [control group], n = 114). During the 1 year follow-up period, 10 patients in Group 1 died, as did 5 in Group 2 and 15 in Group 3. On the basis of an intention to treat analysis, the probability of survival of patients given amiodarone was significantly greater than that of control patients (p less than 0.05). In addition, arrhythmic events were significantly reduced by amiodarone (p less than 0.01). These effects were less marked and not significant for individually treated patients (Group 1). These findings suggest that low dose amiodarone decreases mortality in the 1st year after myocardial infarction in patients at high risk of sudden death.

Amiodarone↗
PubMed1990

Heart valve replacement with the Björk-Shiley and St Jude Medical prostheses: a randomized comparison in 178 patients.

In 178 patients, a randomized prospective comparison between the 60 degrees spherical disc Björk-Shiley (BS) and the St Jude Medical (SJM) heart valve prostheses was performed. Four-week perioperative mortality was zero in the BS (n = 84) and 4.3% in the SJM group (n = 94). During a mean (+/- SD) follow-up of 52 +/- 20 months or 778 patient-years, late cardiac mortality per year was 2.4% in the BS and 2.2% in the SJM group. The yearly thromboembolic rates were 1.4% in the BS and 2.0% in the SJM group. There was no mechanical valve failure or haemolytic anaemia. Paravalvular leaks and major bleeding complications occurred at low rates in both groups (1.1% and 2.2% per year in BS; 0.7% and 1.7% per year in SJM). Functional results were similarly good with 96% of patients with BS valves and 95% of patients with SJM prostheses being in NYHA classes I and II, respectively. We conclude that heart valve replacement with mechanical prostheses can be performed with equally good results using either the Björk-Shiley spherical disc valve or the St Jude Medical bileaflet prosthesis.

Aged↗
PubMed1990

Progressive functional deterioration of bioprostheses assessed by Doppler ultrasonography.

Doppler echocardiography was used to study the function of bioprosthetic heart valves by noninvasive means in 32 patients aged 29 to 72 years at various postoperative intervals. There were 24 Ionescu-Shiley, four Hancock, and four Carpentier-Edwards prostheses, 19 in the aortic and 13 in the mitral position. Initial studies were performed at a mean of 2.3 years after implantation and were repeated one, two, and three years thereafter. Flow velocities in the mitral orifice, left ventricular outflow tract, and ascending aorta, as well as mitral pressure half-time, were measured from pulsed-wave or continuous-wave Doppler recordings. Mitral and aortic valve areas and aortic pressure gradients were calculated. In aortic prostheses the valve area decreased and pressure gradient increased progressively in relation to the time from implantation. The mean value (+/- SD) of the aortic valve area was 67 +/- 17 percent of the manufacturer's nominal value at the first examination and 57 +/- 20 percent one year later, 51 +/- 14 percent two years later, and 46 +/- 11 percent three years later (overall differences, p less than 0.01). In mitral prostheses, reduction of the valve area was not related to the time from implantation. The mean mitral valve area was 45 +/- 12 percent of the nominal value at rest and increased to 68 +/- 18 percent during exercise at a mean of 45 months after implantation. There was no change in these values at the one-year repeat study. It is concluded that in a population with predominantly pericardial bioprostheses, (1) aortic tissue prostheses showed a progressive functional deterioration demonstrable by Doppler echocardiography, most probably due to degenerative changes; and (2) in mitral tissue prostheses, there was no significant reduction of orifice area in relation to time from implantation. Reduction of mitral valve areas may, to some extent, reflect a less than full opening at rest.

Aortic Valve↗
PubMed1990

Diltiazem in ischemia-induced and reperfusion arrhythmias.

The beneficial effect of the calcium antagonist diltiazem on ischemia-induced and reperfusion arrhythmias has been documented in several animal studies. This effect may be due to prevention or reversal of spasms (secondary to prevention of intracellular calcium overload), due to reduction of conduction delay, suppression of after-potentials and triggered activity, or a consequence of inactivation of increased sympathetic activity. The clinical importance of these arrhythmias in humans is still a matter of debate.

Animals↗
PubMed1989

[Acute digitoxin poisoning].

We report a case of severe digitoxin poisoning with--as to our knowledge--the highest plasma concentration reported so far (376 ng/ml). On admission, the patient suffered from nausea and vomiting. The ECG showed a complete AV-block which was managed temporarily by pacing. Phenytoin was given for ventricular tachycardias. The plasma potassium level was 7.4 mmol/l. The elimination of the digitoxin was enhanced with cholestyramine and hemoperfusion. Because of persisting arrhythmias, hyperkalemia and a very high digitoxin level, purified Fab fragments of digoxin-specific antibodies (cross-reacting with digitoxin) were administered. After a first dose of 480 mg nausea disappeared readily, and with a second dose of 480 mg cardiac rhythm disturbances and hyperkalemia were overcome. There were no adverse reactions to treatment. We confirm the effectiveness of digoxin-specific Fab antibody fragments in life-threatening digitoxin intoxication.

Adult↗
PubMed1989

Trial of low-dose aspirin plus dipyridamole versus anticoagulants for prevention of aortocoronary vein graft occlusion.

In a prospective randomised trial, 249 patients who had aortocoronary vein bypass surgery were assigned either to a platelet inhibitory drug regimen or to standard anticoagulant therapy. Treatment was replaced by placebo in half of the patients in each group after 3 months. The platelet inhibitory drug regimen--very low-dose aspirin combined with dipyridamole--was as effective as standard anticoagulant therapy to prevent early and late graft occlusion. Death, myocardial infarction, and severe bleeding occurred significantly more often in patients receiving anticoagulants, whereas mild drug-related gastrointestinal and cerebral side-effects were more common in patients taking platelet inhibitory drugs. Antithrombotic treatment should be continued for at least 1 year after coronary artery bypass graft surgery.

4-Hydroxycoumarins↗
PubMed1989

Sudden cardiac death after aortic valve surgery: incidence and concomitant factors.

A retrospective analysis of 599 consecutive patients after aortic valve surgery aged 7-82 years (mean 56) was performed. During a follow-up of 1-14 years (mean 4.7 years) a 4-week perioperative mortality of 6.9% and a late annual mortality of 3.6% were observed. Sudden cardiac death was the most frequent single cause of death, accounting for 24% of all deaths. Patients dying suddenly were younger than patients dying from other causes (51 +/- 17 vs. 59 +/- 14 years, p less than 0.05) and showed more left ventricular hypertrophy by electrocardiographic criteria when compared with matched survivors (mean Estes score 5.2 +/- 2.4 vs. 2.8 +/- 1.9; p less than 0.01) and with patients dying nonsuddenly (mean Estes score 5.2 +/- 2.4 vs. 1.8 +/- 1.8; p less than 0.01). Ventricular premature beats in the resting electrocardiogram were more prevalent in patients dying suddenly than in matched survivors (55 vs. 20%; p less than 0.025) as well as in patients dying from other causes (55 vs. 25%; p less than 0.05). In addition, there were more intracardiac conduction disturbances and more ungrafted coronary vessels with insignificant stenoses at the time of surgery in sudden death patients. Our findings suggest that after aortic valve replacement patients with left ventricular hypertrophy, bundle-branch block, and ventricular premature beats in the resting electrocardiogram are at increased risk for sudden cardiac death. A possible etiological role of concomitant coronary artery disease must be considered.

Adolescent↗
PubMed1989

[Transthoracic color Doppler echocardiography in the diagnosis of insufficiency of heart valve prostheses. A comparison with conventional Doppler sonography].

Color-coded and conventional pulsed wave/continuous wave Doppler detection of valvular or paravalvular regurgitation in 59 patients with 67 cardiac valve prostheses were compared; 21 patients had known regurgitation determined by auscultation. Analysis of the color-coded Doppler findings was made from videotape and blinded as to patient identity and clinical findings. Conventional Doppler Sonography detected 36 instances of aortic and 3 of mitral prosthetic regurgitation. Color-coded Doppler investigation detected 27 instances of aortic and 1 of mitral prosthetic regurgitation resulting in a sensitivity of 72% and specificity of 100% as compared to conventional Doppler sonography. All 21 patients with a regurgitant murmur had pathological conventional Doppler findings, but 3 of them did not show regurgitant flow in the color-coded Doppler examination. The apical four chamber view contributed most to the colour-coded Doppler detection of regurgitant flow, followed by the parasternal long axis view.

Adult↗
PubMed1989

Increasing incidence of multiple sclerosis in South Lower Saxony, Germany.

In the epidemiological area of South Lower Saxony the prevalence of multiple sclerosis increased from 51/100,000 in 1969 to 99 in 1986. The mean annual incidence increased from 2.6 for the period from 1964-1974 to 4.6 for 1975-1985. This trend is significant (p = 0.0068). Diagnostic criteria, methods of case finding and analysis of the data remained stable. Minor necessary changes as for example due to new data protection laws and new handling of early cases by practising physicians can hardly explain this significant increase. In consideration of similar reports from all over the world biological exogenous factors are suspected but remain to be identified.

Adult↗
PubMed1988

[Thrombolysis in acute myocardial infarct. Initial experiences in a Swiss university hospital].

Preliminary experience with thrombolytic therapy in patients with acute myocardial infarction and its practicability in a CCU of a Swiss university hospital are presented. Out of 674 patients with a transmural or non-transmural infarction, 72 (11%) have been treated with thrombolytic agents since March 1986. 53 of these patients were included in the "European Cooperative Study Group" multicenter trial and treated with recombinant tissue plasminogen activator (rt-PA) or placebo; the other 19 patients received streptokinase i.v. with the same inclusion/exclusion criteria. The results corresponded to the well known effects of early thrombolysis with improvement in infarct size reduction, cardiac performance and early mortality.--The importance of the time factor and the implications regarding information of potential patients and practitioners and organization of rapid hospitalization are outlined. Follow-up (after a mean of 14 months) of our 72 thrombolysis patients revealed a high percentage of patients still dependent on medical care, reduced physical capacity in almost half of the patients and (a favourable result) a large number of patients who stopped smoking after the infarction. --In view of the slight additional stress caused by this therapy for patients, physicians and nursing staff, the use of thrombolytic agents in acute myocardial infarction should (with strict inclusion/exclusion criteria) be rapidly generalized in the hospitals of Switzerland.

Clinical Trials as Topic↗
PubMed1988

Prospective controlled randomized trial of prophylactic antiarrhythmic therapy in postmyocardial infarction patients with asymptomatic ventricular arrhythmias--study design and initial results.

In order to assess the effect of prophylactic antiarrhythmic therapy in asymptomatic patients with persistent complex ventricular ectopic activity after myocardial infarction, a prospective controlled trial was started in 1981 and is still ongoing. Until August 1986, 965 consecutive patients less than or equal to 70 hospitalized for acute myocardial infarction were screened without antiarrhythmic drugs by 24-h ECG before discharge from the hospital. In this group, 238 patients (28%) had ventricular arrhythmias Lown class III-IVb during at least 2 of 24 hours; they were randomly assigned to three treatment groups: (1) individualized antiarrhythmic therapy based on efficacy in multiple 24-h ECGs and drug level determinations (starting with mexiletine or quinidine; n = 79), (2) treatment with low-dose amiodarone (200-400 mg/day after a loading phase; n = 73), and (3) no antiarrhythmic therapy (n = 86). The three groups were comparable regarding age, gender, previous infarction, Q-wave infarction, ejection fraction, as well as incidence and severity of ventricular ectopic activity. Follow-up, including 24-h ECGs, was performed after 3, 6, and 12 months. Based on the results of this study which will be completed by the end of June 1988, it should be possible to estimate the benefit--or harm--of antiarrhythmic drug therapy as well as its cost in postmyocardial infarction patients with asymptomatic ventricular ectopic activity and to decide whether such treatment may improve survival.

Aged↗
PubMed1988

Heart valve replacement with St. Jude Medical valve prosthesis. Long-term experience in 743 patients in Switzerland.

Between November 1978 and June 1986, 828 St. Jude Medical valves were implanted in 743 patients whose mean age was 57 years (range, 1-83 years) and who had been admitted to the University Hospitals in Basel, Berne, and Lausanne, Switzerland. Aortic valve replacement was performed in 456 patients, mitral valve replacement in 200, tricuspid valve replacement in six, double valve replacement in 77, and triple valve replacement in four. In 187 patients, additional surgical interventions were performed. Operative mortality was 1.6%, and the 4-week postoperative mortality was 4.0%. During a mean follow-up period of 2.6 years, the annual mortality rate was 3.1%, and the annual cardiac mortality rate was 2.1%. The thromboembolic rate per 100 patient-years was 1.3 after aortic valve replacement, 3.0 after mitral valve replacement, and 1.0 after multiple valve replacement. The incidence of major bleeding was 1.3 per 100 patient-years. Valve dysfunction attributable to thrombotic obstruction occurred in three patients, and that attributable to leaflet dislocation in one (annual dysfunction rate, 0.2%). Twelve patients developed infectious endocarditis, six of whom died. However, in four patients, reoperation and, in two patients, antibiotic treatment alone were successful in treating the infection. A paravalvular leak necessitating reoperation developed in 10 patients. In three patients, the leak was caused by infectious endocarditis. Reoperation had no operative mortality. In three patients (0.4%), a mild hemolytic anemia was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Effect of amiodarone on sinus node function in patients with sick sinus syndrome.

The effect of amiodarone on sinus node function has been studied in 9 patients with symptomatic sick sinus node as documented by Holter-ECG. All patients had programmable dual-chamber pacemakers. Sinus node activity was assessed by intermittently inhibiting the pacemakers before and after four weeks of oral amiodarone treatment. Sinus node function was not altered by amiodarone in 5 patients but was severely depressed in 4 patients. Thus, it is concluded that amiodarone cannot be used safely in all patients with the tachybrady syndrome for the treatment of symptomatic tachyarrhythmias without concomitant pacing.

Aged↗
PubMed1987

[Doppler sonography in cardiologic diagnosis].

Ultrasonic Doppler analysis of intracardiac blood flow is a technique complementary to echocardiographic imaging, and an important tool in non-invasive diagnosis. Doppler ultrasonography enables the evaluation of systolic murmurs, particularly the calculation of pressure gradients and valve areas in stenotic lesions. In patients with aortic stenosis, there was a very close correlation of invasive and non-invasive pressure gradients (r = 0.92). In patients with mitral stenosis, invasive and non-invasive valve areas were correlated as well (r = 0.78). In addition, regurgitant and shunting jets can easily be traced and assessed at least semi-quantitatively by using 2D-colour flow mapping, or 2D-duplex scanning. Doppler echocardiography is a prime aid in the evaluation of children and young adults, in whom cardiac catheterisation can often be omitted because there is no need for coronary arteriography. It is also an important tool in the follow-up of patients with cardiac valve prostheses, in particular bioprostheses. A time-dependent reduction of valve areas was noted in patients with aortic bioprostheses (r = -0.80).

Aortic Valve Insufficiency↗