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Biomedical subjects

M Tauchert

Publications and source records attributed to M Tauchert.

At least 37 records · Page 2Linked to original sources

Beneficial effects of intracoronary nifedipine during percutaneous transluminal coronary angioplasty.

In twelve patients with coronary heart disease and hemodynamically significant coronary artery stenoses (LAD: 11, LAD plus RCA: 1) the effect of intracoronary nifedipine, 0.2 mg, on PTCA-related myocardial ischemia was evaluated. The severity of angina pectoris during balloon inflation was not significantly reduced by nifedipine, whereas the sum of ST segment alterations in Einthoven and Goldberger leads on inflation was significantly decreased by the drug. Before inflation intracoronary nifedipine lowered the systolic arterial blood pressure significantly, whereas diastolic and mean aortic pressure and heart rate remained unchanged. At the end of the inflation period heart rates were significantly faster after nifedipine, and the heart rate-blood pressure product higher with nifedipine. No significant correlations could be calculated between the extent of ST segment alterations and any of the hemodynamic parameters. From our results we conclude that, besides the possibility of ventricular afterload reduction, the beneficial cardioprotective effect of intracoronary nifedipine may mainly be attained by the local "cardioplegic" action of this substance.

Adult↗

[Endocardial cardioversion--a new method for treating recurrent ventricular tachycardia].

The effect of endocardial cardioversion was investigated in 17 patients (aged 26-76 years), ten of them with ventricular tachycardia, either spontaneous or initiated by programmable stimulation. During a total of 14 days of observation there were 33 episodes of spontaneous or induced ventricular tachycardia. A special cardioverter catheter had been placed into the right ventricle and endocardial microshocks were given ranging from 0.05-2.0 J. All patients could feel the shock, but in most instances it was mild to moderate, in only one painful. The tachycardia was slowed in 20% of all microshocks, moderate acceleration occurred in 6%, while in 71% the tachycardia rate remained unchanged. In 7 out of 65 microshocks sinus rhythm occurred spontaneously, after an interval in which the tachycardia slowed. Atrial fibrillation was induced in 6% of cases, but there was no instance of ventricular fibrillation. Reversion directly to sinus rhythm after endocardial cardioversion occurred in 26 of 33 episodes of ventricular tachycardia, while in 7 episodes the tachycardia rate slowed. In no case was it necessary to use external DC cardioversion to terminate a ventricular tachycardia. Threshold values for successful cardioversion of ventricular tachycardia averaged 0.77 (+/- 0.63) J. In one patient, atrial flutter with a relatively high A-V conduction rate was converted into atrial fibrillation by an intra-atrial microshock of 5.0 J. Thus endocardial cardioversion proved effective and safe in terminating ventricular tachycardia, even in patients in whom anti-tachycardic ventricular pacemaker stimulation had failed. The method is apparently not suitable for the conversion of supraventricular tachy-arrhythmias to sinus rhythm.

Adult↗

[Effect of nitroglycerin plasters on hemodynamics and stress tolerance of patients with coronary heart disease].

The haemodynamic and antianginous efficacy of percutaneous nitroglycerin was evaluated in 24 patients with coronary heart disease. Groups of 8 patients each received one, two or four patches (nitroglycerin liberation 5 mg per patch within 24 hours). Prior to application and after 1 and 2 hours cardiac frequency, arterial and pulmonary arterial pressures and exercise tolerance were assessed. Cardiac frequency and arterial pressure showed no relevant changes after application of patches. The mean pulmonary arterial pressure decreased after application of one or two plasters by 18.5 and 22.2% at rest and by 12.7 and 21.1%, respectively, during exercise. The working capacity showed a trend towards improvement only. With four nitroglycerin patches the mean pulmonary arterial pressure at rest was lower by 26.2% and during exercise by 39.1%. The working capacity rose significantly by 48.7%. Comparison of these effects with oral single dosage of 20 mg 5-isosorbide mononitrate (ISMN) showed that two simultaneously administered plasters did not achieve efficacy of 20 mg 5-ISMN, four plasters, however, were more effective.

Adult↗

[Long-term therapy with nitrates. Relation between dosage and tolerance effect].

In 56 patients with angiographically-documented coronary artery disease, the longterm effects of isosorbide dinitrate (ISDN) and isosorbide 5-mononitrate (5-ISMN) on exercise hemodynamics and exercise capacity were assessed. The hemodynamic and antianginal acute and longterm effects of the respective agents were objectively analyzed on the basis of the tested parameters of mean pulmonary artery pressure and work capacity (watts X minutes). These parameters are unaffected by placebo and show reproducible changes at rest and during exercise after drug administration. After the standard 20 mg dose of ISDN or 5-ISMN, both at rest and during exercise, there was a marked decrease in pulmonary artery pressure as well as an increase in exercise capacity. The acute effects of 60 mg ISDN or 50 mg 5-ISMN were not substantially more marked than those of the 20 mg doses. During longterm treatment with 20 mg ISDN or 5-ISMN three times daily there was no attenuation of the hemodynamic effects, that is, no tolerance development; the increase in exercise capacity was maintained. In contrast, at the end of the four-week treatment period with 60 mg ISDN or 50 mg 5-ISMN three times daily there was a marked attenuation of the hemodynamic effects as well as the associated exercise capacity. The results of this study do not enable delineation of the mechanism responsible for the attenuated effect during high-dose treatment. Most probably, it is due to a complex process, in which, in addition to pharmacokinetics and pharmacodynamics, alterations in various reflex and adaptive mechanisms also play a role.

Adult↗

[Value of the dipyridamole test in the diagnosis of coronary heart disease. Comparison with the stress ECG and coronary angiogram].

In 500 patients suffering from angina pectoris (454 males, 46 females) in whom coronary angiography had been performed a dipyridamole test was carried out. The test was positive in 319 of 396 patients with stenosing coronary heart disease (sensitivity 80%); ECG changes typical of ischaemia were demonstrated in 51%. The exercise ECG test was positive in only 68% of 229 patients with coronary heart disease. Among 104 patients without stenosing coronary heart disease the dipyridamole test was false-positive in 47, giving a specificity of 55%, while in 17 (16%) there were false-positive ECG-changes. The exercise test was falsely positive in 20 of 38 patients without stenosing coronary heart disease (specificity of 47%). Coronary blood flow was measured with the argon technique in 19 of 47 with a false-positive dipyridamole test and three with a false-positive exercise ECG. Maximal pharmacologically induced coronary blood flow was significantly reduced in all so that the diagnosis of "atypical coronary heart disease" or "small vessel disease" was made. The dipyridamole test or the exercise ECG test were falsely positive in these patients only with regard to the coronary arteriogram, correctly positive, however, in relation to angiographically non-demonstrable coronary blood flow abnormalities. The dipyridamole test is complementary to the exercise ECG test and has comparable accuracy. The same precautions must be observed for both tests.

Angiography↗

Dose dependence of tolerance during treatment with mononitrates.

In order to test the clinically supposed development of tolerance during chronic high-dose nitrate therapy, we studied a total of 24 patients with angiographically proven coronary heart disease at rest and during ergometric exercise (supine position, 50 w for 3 min). Pulmonary arterial pressure (PAP, floating catheter), arterial blood pressure (cuff method), cardiac output (Fick principle), heart rate, and exercise capacity (w X min) were measured at rest and exercise before and during chronic (4 weeks) oral therapy with 5-isosorbide mononitrate (5-ISMN), 3 X 20 mg/day (n = 14) and 3 X 50 mg/day (n = 10). After acute administration, both doses of 5-ISMN decreased mean PAP at rest and during exercise (rest: by 25% with 20 mg and by 29% with 50 mg; exercise: by 30% with 20 mg and by 45% with 50 mg), whereas cardiac output and stroke volume were only reduced by 5-ISMN at rest. During chronic treatment with 60 mg and 150 mg 5-ISMN, and additional administration of 20 mg or 50 mg respectively lowered PAP at rest by 15% and 19%; during ergometric exercise PAP was 22% and 14% lower than during ergometry before any drug treatment. The exercise capacity slightly increased during treatment to 60 mg 5-ISMN, whereas it decreased by 25% on chronic treatment with 150 mg 5-ISMN per day. Our results show that acute administration of 5-ISMN in either dose (20 mg and 50 mg) exerts unloading effects on the heart and will increase the exercise tolerance. In contrast to the higher dose of 150 mg 5-ISMN per day, chronic treatment with the lower dose of 60 mg 5-ISMN daily will not result in drug tolerance.

Adult↗

Long-term treatment of patients with coronary heart disease using isosorbide dinitrate, nifedipine and molsidomine.

1. After initial acute administration of 20 or 60 mg ISDN, 2 mg molsidomine and 20 mg nifedipine, a clear effect on the circulation and an increase in work tolerance is detectable. 2. Following 4 weeks' treatment with 3 X 20 mg ISDN, there is no essential loss of action in the venous branch or with respect to working capacity. 3. After 4 weeks' treatment with 3 X 60 mg ISDN, the improvement in working capacity is partially retained, but the action on the venous branch is significantly poorer. 4. During 4 weeks' treatment with 3 X 20 mg nifedipine, there is no essential loss of action in the arterial or venous branches, or with respect to working capacity. 5. Our results with continuous high doses of ISDN indicate that high doses should be used only in monitored exceptions.

Adult↗

[Echinococcosis involvement of the heart].

A case report is given of a 37-year-old patient who had echinococcus infestment the heart. Diagnosis was established after drainage of the pericardium, when cysts of a diameter between 0.5 and 3 cm were evacuated. During this procedure the pericardium and the left ventricle were searched and revised extensively and drug therapy with Mebendazole was instituted. In spite of that a new cyst developed in the pericardium and a big cyst in the abdomen, was found which had practically transformed the whole left lobe of the liver into a cyst. Both lesions were removed surgically. It must be emphasized 1) that a very careful search of all organs liable to harbour echinococcus should be performed in patients who have cardiac involvement of the disease, 2) that chemotherapy will not prevent with necessity the development of fertile elements which could not be removed during surgery and 3) that patients have to be followed through several years in order to evaluate the success of therapy.

Adult↗

[5-isosorbide mononitrate at rest and on exercise in coronary heart disease: acute and long-term effect].

Haemodynamic effects of 5-isosorbide mononitrate (5-ISMN) were studied at rest and on exercise in 31 patients with angiographically confirmed coronary heart disease. A decrease in arterial blood pressure and mean pulmonary artery pressure without significant change in heart rate, cardiac output and stroke volume occurred both at rest and on exercise after 20 mg of 5-ISMN to 12 patients. Administration of 50 mg 5-ISMN to 19 patients achieved greater decrease in mean pulmonary artery pressure; cardiac output and stroke volume were highly significantly reduced at rest, while on exercise both cardiac output and stroke volume remained unchanged. Ten patients, in whom after a single dose of 50 mg 5-ISMN the mean pulmonary artery pressure at rest and on exercise had decreased 28% and 45%, respectively, with a definite rise in exercise tolerance, repeat acute administration of a single dose of 50 kmg 5-ISMN produced a fall in mean pulmonary artery pressure at rest by 20% after 50 mg three times daily for four weeks. On exercise the fall was only 14% below the control levels before treatment. In addition, exercise tolerance was reduced. These results indicate that acute administration of 5-ISMN at rest and on exercise decreases cardiac work load. But on chronic administration of high doses, tolerance to the drug may develop.

Adult↗

Electrophysiological effects of cardioselective and non-cardioselective beta-adrenoceptor blockers with and without ISA at rest and during exercise.

1 In 46 patients (16 female and 30 male), aged between 18 and 73 years and effect of acute beta-adrenoceptor blockade with i.v. pindolol, acebutolol and atenolol has been studied at rest and during ergometric exercise, during routine intracardiac His bundle investigations. 2 At rest the functional parameters of the sinus node were impaired most markedly by atenolol. A-V nodal conduction was more depressed with acebutolol and atenolol than with pindolol. The His-Purkinje system conduction remained unaffected by all three beta-adrenoceptor blocking agents. 3 During ergometric exercise the depressant action of beta-adrenoceptor blockade on sinus nodal function with lower heart rates and on A-V nodal conduction with slower conduction velocities was equieffective with pindolol, acebutolol and atenolol. His-Purkinje system conduction again remained unchanged with one exception that after administration of pindolol, conduction rate during exercise was faster than before beta-adrenoceptor blockade. 4 It may be concluded that, in patients with low heart rates, an antagonist such as pindolol with relatively pronounced intrinsic sympathomimetic activity can be considered to be the drug of choice. In contrast, patients with higher heart rates at rest should be treated with a cardioselective betablocker without ISA. Patients with overt Sick Sinus Syndrome should not be given beta-adrenoceptor blockers at all. 5 Physical activity may change (improve or impair) the antiarrhythmic potency of beta-adrenoceptor blockers used in the treatment of supraventricular tachycardias or tachyarrhythmias.

Acebutolol↗