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Biomedical subjects

F Burkart

Publications and source records attributed to F Burkart.

At least 109 records · Page 6Linked to original sources

[Aortocoronary bypass operation in the elderly patient: favorable long-term course].

Age has been identified as an independent risk factor for coronary artery bypass grafting (CABG). We evaluated, therefore, the perioperative phase and long-term prognosis of all patients over the age of 64 (n = 80), who had been operated on for coronary heart disease at the University Hospital of Basel/Switzerland between 1979 and 1983. These elderly subjects were compared to 80 patients, 50 to 60 years old at the time of CABG, who were matched for degree of angina pectoris, coronary artery disease, left ventricular ejection fraction, sex and year of operation (matched-pairs analysis). Evaluation of long-term prognosis was based on regular clinical controls and on a questionnaire, sent to the patients in June 1984. During the perioperative phase 3 patients over 64 died versus 0 in the group of patients 50-60 years old. There were more complications in the older group (perioperative myocardial infarction 10 vs. 4, pulmonary embolism 2 vs. 0, cerebro-vascular insult 4 vs. 0). Three vs. one permanent pacemaker had to be implanted for irreversible AV-block. The difference in hospital stay, 21 vs. 19 days, was not significant. The cumulative survival rate was in both groups 95% after one year and 86 vs. 92% 5 years after CABG (difference not significant), despite the fact that significantly more elderly patients have had myocardial infarction prior to CABG. After an average follow-up of 28 months, 72% vs. 60% were without thoracic pain; 63 vs. 49% considered themselves in a good overall condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

[Incidence and course of complex ventricular arrhythmias in myocardial infarct as a function of infarct size, heart function and persistent ischemia].

Incidence and course of complex ventricular ectopic activity (VEA) after myocardial infarction was prospectively evaluated in 217 patients in relation to infarct size, location, ventricular function and signs of persistent ischemia. Complex VEA (Lown greater than III) was found acutely in 138 patients (63.6%) and at hospital discharge in 42 (19.3%). Of 79 patients with VEA Lown less than or equal to III in the first 24 hours, 93.7% remained VEA-free at follow-up. Patients with persistent complex VEA differed from those who became VEA-free only in left and right ventricular ejection fraction, whereas all the other infarct related factors had no influence on the course of VEA.

Aged↗

[Swiss pacemaker statistics in 1983].

The data on 98% of pacemakers implanted in 1983 in Switzerland were analyzed and compared with previous years. The number of first implantations slightly increased to 240 per million population per year (1982: 216). 80% of pacemakers used were multiprogrammable, and 7.7% were physiological pacemakers. Counting only the centers implanting physiological pacemakers, the number is 14.5%. Complications demanding reinterventions decreased slightly. This applied especially to complications related to implantation techniques.

Aged↗

[Second prevention following myocardial infarct].

The prophylactic effect of beta-blockers in reducing reinfarction and cardiac death after acute myocardial infarction has been proven convincingly in several studies. Whereas anticoagulation is not generally accepted in secondary prophylaxis, it has been shown that in patients where treatment with anticoagulants could be performed without difficulty, withdrawal of the drug is disadvantageous. Large-scale studies have shown the relatively slight effect of drugs which inhibit platelet aggregation. The indication for these drugs, and "prophylactic" surgery to improve prognosis, are discussed with respect to the various risk groups.

Adrenergic beta-Antagonists↗

Reproducibility of left ventricular volume determinations with use of a semi-automated system.

Reliability of a computer-assisted system for determination of left ventricular volumes was judged by multiple measurements of rotation ellipsoids, cadaver hearts, and cineangiograms from patients. The volume measurements in cadaver hearts provided a volume correction factor necessary for reproducible results. Variation coefficient for intraobserver and interobserver variability did not exceed 2.3% when calculated using rotation ellipsoids and was highest at 12.0% for the end-systolic volumes derived from patient films. When appropriate calibration methods are employed, different observers can make reliable left ventricular volume measurements aided by such systems.

Cardiac Volume↗

Persisting symptoms despite permanent pacing. Incidence, causes, and follow-up.

Persisting symptoms, consisting of palpitations, dizziness, or syncope, were found in 49 of 570 consecutively followed patients (8.6 percent) with permanent pacemakers (PM). Among 540 patients with ventricular PM, 19 had syncope and 24 dizziness; among 30 patients with dual-chamber PM, five had palpitations and one dizziness. Symptoms were PM-related in 17, caused by tachyarrhythmias in 12, of noncardiac origin in 16, and of unknown origin in four patients. Holter monitoring was necessary for evaluating the persisting symptoms in 36 patients and helpful in 32 studies (89 percent). Symptoms were relieved in all patients with PM-related causes but only in 6/16 patients (38 percent) with syncope or dizziness of noncardiac origin despite various therapeutic measures. In patients with either documented tachyarrhythmias or unknown cause of syncope or dizziness, antiarrhythmic drugs led to symptomatic improvement in 11 of 12 treated patients during an average follow-up of 15 months. We concluded that: (1) persistent syncope, dizziness, or palpitations occurred in 8.6 percent of 570 patients after PM-implantation; (2) symptoms were more frequent but less severe in patients with dual-chamber PM than in those with ventricular PM; (3) tachyarrhythmias as a possible cause of symptoms were found in 25 percent of patients; (4) symptomatic improvement was noted in 28 of 29 patients when a PM-related cause or tachyarrhythmias were treated.

Adult↗

Antianginal drug effects on normal, ischemic and scar myocardial segments in man.

In order to assess acute effects of nitroglycerin, nifedipine and metoprolol on normal, ischemic and scar myocardial segments in man, non-invasive hemodynamic and radionuclide measurements of left ventricular function were performed. Sixteen patients with single left anterior descending (LAD) disease were studied at rest and during exercise: 9 patients with angina and exercise-induced ischemia (LAD stenosis) and 7 patients with previous transmural myocardial infarction and no ischemic changes at thallium imaging (LAD occlusion). Effects on regional ejection fraction were compared between involved antero-septal and normal postero-lateral areas. Global ejection fraction at rest was unchanged after nitroglycerin, increased after nifedipine and decreased after metoprolol. In patients with ischemia, improvement in exercise ejection fraction after all drugs was due to increased regional ejection fraction in ischemic segments, i.e. a real anti-ischemic effect could be demonstrated. In regions of myocardial scar, regional ejections fraction was not changed after either drug. In normal areas, regional ejection fraction remained unchanged after nitroglycerin and nifedipine but decreased after acute beta-blockade. Despite the very similar anti-ischemic effects of all drugs, underlying hemodynamic mechanisms were quite different: Reduction in preload and afterload after nitroglycerin, vasodilatation and reflex sympathetic activity after nifedipine and reduction in double product and contractility after metoprolol. Thus, the mode of action of nitroglycerin, nifedipine and metoprolol on normal, ischemic and scar myocardial segments could be demonstrated in man. Non-invasive antianginal drug testing as shown in this study should allow optimal medical therapy for patients with chronic ischemic heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Incidence and extent of right ventricular functional disorders following the 1st myocardial infarction].

A series of 63 patients were studied by gated radionuclide angiocardiography 51/2 weeks after their first acute myocardial infarction. Left (LVEF) and right (RVEF) ventricular ejection fraction were assessed in three groups of patients: 12 patients with transmural anterior infarctions, 35 patients with transmural inferior infarctions and 16 patients with non-transmural infarctions. LVEF was depressed only in the group of patients with anterior infarctions (34.4 +/- 16.3%) but remained within normal limits in the other two groups. RVEF was reduced in 64% of patients with inferior infarctions; the mean value in this group was 36.3 +/- 10.2% (normal range 48 +/- 8%, p less than 0.02). In the other two groups RVEF was only rarely reduced and the mean values were within normal limits. Regional wall motion abnormalities ( WMA ) were found in 47% of all patients, those localised in the left ventricle matching ECG localisation of necrosis in 86% of cases. Only patients with infarctions of the inferior left ventricular wall were found to have WMA in the right ventricle. Functional signs of ischemia (decrease of RVEF or LVEF during physical exercise) were found in 34% of patients with transmural infarctions and 57% of patients with non-transmural infarctions. Radionuclide angiocardiography showed itself a valuable method for assessing persistent dysfunction after acute myocardial infarction not only of the left but also of the right ventricle, a phenomenon not easily detected clinically.

Female↗

[Drug therapy of angina pectoris].

In patients without heart failure and with exercise-induced angina pectoris, betablockers are still the treatment of choice. The pharmacological differences within the betablockers are of minor importance clinically. Patients with angina at rest, or with a considerably changing effort threshold, are suspect for additional coronary spasms. Here calcium antagonists, and possibly nitrates, should be given first. A combination of these three treatments often proves beneficial. Amiodarone, which in the beginning was only rarely used because of its complex pharmacokinetics, is now generally accepted as an effective and well-tolerated drug for angina. In unstable angina, medical treatment varies according to the differing clinical symptoms. In addition to immobilization and anticoagulation, prolonged pain attacks are treated with intravenous nitrates. If the symptoms persist, combination of antianginal drugs as described above, sometimes in high doses, is necessary in order to postpone selective coronary angiography and bypass operation by one to two weeks. Otherwise these procedures must be performed after intraaortic balloon pumping has been instituted.

Adrenergic beta-Antagonists↗

[Asymptomatic ischemia following myocardial infarct].

To assess the incidence of silent ischemia after myocardial infarction, a prospective series of 100 consecutive patients was studied 5 weeks after the acute event. Objective evaluation of myocardial ischemia included a 9-lead ECG, thallium-201 scintigraphy and radionuclide ventriculography, each at rest and during symptom-limited bicycle ergometry. Diagnostic criteria were ECG: greater than or equal to 1 mm horizontal or downsloping ST depression or greater than or equal to 1 mm ST elevation; thallium scintigraphy: a clearly reversible perfusion defect at rest, detectable only after exercise; radionuclide ventriculography: an exercise-induced decrease in global LVEF greater than or equal to 5% and/or in anyone regional EF greater than or equal to 14%. Presence of ischemia was assumed if at least 2 of 3 objective ischemic signs were found. This was the case in 28 of 100 patients. During exercise, 15 of 100 patients complained of chest pain, but only 8 (54%) had objective evidence of ischemia. Thus, silent ischemia was demonstrated in 20 of 100 patients. The sensitivity of both nuclear cardiology procedures was markedly superior to that of the ECG in diagnosing post-myocardial ischemia.

Coronary Disease↗

[Re-entry tachycardias: a fragment problem during physiologic heart stimulation].

In a prospective study, reentry tachycardias (RT) due to retrograde VA-conduction were sought in 30 patients after implantation of an atrial synchronous (VDD, DDD) pacemaker (PM) by frequent clinical controls and by 24-hour Holter monitoring. At least one RT was detected in 9/30 patients (in 5 during clinical control, in 4 on Holter monitoring only). 6 patients had symptoms due to RT (6 had palpitations, 1 complained of dizziness and 1 of ischemic heart pain). RTs were initiated by VPBs in 6 patients, by sinus bradycardia in 2 (VDD) and by magnet application in 1. Rates of RT varied from 100 bpm to 128 bpm. RT necessitated reprogramming of the PM in 5 patients (in 3 of them reprogramming to VVI-stimulation). RTs are thus a frequent complication after implantation of an atrial synchronous pacemaker.

Adult↗

[Swiss pacemaker statistics of the year 1982].

The data of 96% of pacemaker implantations in Switzerland is analyzed and compared with previous years. The numbers of first implantations slightly increased to 216 per million population per year. The percentage breakdown of the various indications remain unchanged. Two thirds of the pacemakers implanted were multiprogrammable. Implantation of physiologic pacemakers has increased to 8.8% in recent years. Complications requiring reintervention decreased despite the increase in first implantations.

Adolescent↗

[Atypical and ischemic chest pain more than a year after aortocoronary bypass].

215 consecutive patients were followed up for more than a year (22 +/- 9 months) after aortocoronary bypass. Recurrence of ischaemic (anginal) and atypical chest pain was assessed: 54% of all patients were completely without pain postoperatively, 76% free of angina and 93% improved by at least one NYHA class. The frequency of severe atypical chest pain was similar pre- and postoperatively (11% and 13%, respectively), but nearly double that of postoperatively severe angina (13% vs 7%, P less than 0.05). Limiting atypical chest pains in patients with pre-operative atypical chest pain was much more frequent postoperatively than in patients who pre-operatively had only angina (30% vs 11%, P less than 0.005). These two patient groups did not differ with respect to age, sex, degree of vessels disease, exercise-induced ischaemia or number and patency of bypasses. Thus, exercise-limiting atypical chest pain can influence the surgical results in up to 30% of patients with pre-operative atypical chest pain (with or without typical angina).

Adult↗

Influence of age on pulmonary haemodynamics at rest and during supine exercise.

To determine the effects of age on the pulmonary circulation at rest and on exercise we analysed the results of right heart catheterization studies performed in 125 asymptomatic subjects aged 14-68 years, who were healthy or had indispositions which did not impair cardiac or pulmonary function. Age accounted for less than 10% of total variation in resting values of right atrial, pulmonary artery and wedge pressures, and of cardiac output. The pulmonary artery-wedge pressure gradient and flow resistance at rest significantly increased with age. On exercise there were significant increases with age in right atrial, pulmonary artery and wedge pressures, pulmonary to wedge pressure gradient and flow resistance, but cardiac output was not influenced by age. Pulmonary circulation variables at rest are mainly influenced by sex and size, but during exercise significant effects of age are apparent.

Adolescent↗

Comparative effects of nitroglycerin, nifedipine and metoprolol on regional left ventricular function in patients with one-vessel coronary disease.

To compare acute effects of nitroglycerin (0.8 mg sublingually), nifedipine (5 ng/kg/min i.v.) and metoprolol (0.15 mg/kg i.v.) on normal, ischemic and scarred myocardial segments in man, we performed simultaneous hemodynamic and radionuclide measurements of left ventricular functions. Sixteen patients with isolated left anterior descending (LAD) disease were studied at rest and during exercise. Nine patients had angina and exercise-induced ischemia (LAD stenosis) and seven patients had previous transmural myocardial infarction and no ischemic changes during thallium imaging (LAD occlusion). The effects of the drugs on regional ejection fraction of the involved anteroseptal region and the normal posterolateral area were compared. Global ejection fraction at rest did not change after nitroglycerin, increased after nifedipine and decreased after metoprolol. In patients with ischemia, the exercise ejection fraction improved after all drugs due to increased regional ejection fraction in ischemic segments: i.e., a regional antiischemic effect evidenced by improved regional function could be demonstrated with all three agents. Regional ejection fraction increased from 35.8 +/- 19.5% to 66.2 +/- 15.2% (+/- SD) after nitroglycerin (p less than 0.001), to 61.7 +/- 8.7% after nifedipine (p less than 0.001), and to 48.4 +/- 7.0% after metoprolol (p less than 0.01). In regions of myocardial scar, regional ejection fraction was not changed after any drug. In normal areas, regional ejection fraction remained unchanged after nitroglycerin and nifedipine, but decreased after metoprolol. Despite similar antiischemic effects of all three drugs, underlying hemodynamic mechanisms were quite different and may provide a rationale for combined forms of treatment. These results may help to select optimal drug combinations to improve myocardial performance in patients with chronic ischemic heart disease.

Adult↗