PubMed Health⌕ Search

Biomedical subjects

M Zabel

Publications and source records attributed to M Zabel.

At least 19 recordsLinked to original sources
PubMed1992

Short- and long-term efficacy and safety of flecainide acetate for supraventricular arrhythmias.

This report summarizes efficacy and safety data on the use of flecainide acetate for supraventricular arrhythmias. For this purpose, 60 original articles were identified by a literature search representing data from 1,835 treatment courses. In 18 trials, flecainide was administered intravenously; in 19, orally; and in 23, both forms of therapy were applied. There were 5 placebo-controlled and 12 comparative studies, whereas data from uncontrolled studies were represented in 43 articles. Short-term flecainide administration terminated atrial fibrillation in 65% of attempts and terminated atrial flutter in 28%. The drug was effective during long-term therapy for atrial fibrillation in 49% of patients, with similar efficacy rates in 11 comparative trials and in 16 uncontrolled studies. In randomized, placebo-controlled studies in patients with paroxysmal atrial fibrillation, flecainide was shown to reduce significantly the number of attacks, to prolong the time between attacks, and to improve quality of life. In patients with atrioventricular (AV) reciprocating tachycardias, acute drug administration was successful in 72%; 83% of patients with AV nodal reentrant tachycardias and 74% exhibiting arrhythmias associated with the Wolff-Parkinson-White syndrome responded acutely. During long-term therapy, efficacy rates were 70%, 78%, and 69%, respectively. Ectopic atrial tachycardia responded in 86% and 95% of patients treated with flecainide acutely or chronically. Data concerning drug-related side effects were available for 1,794 of 1,835 treatment courses (98%). Overall, 352 of 1,794 patients (20%) reported at least one non-cardiac or cardiac adverse experience.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1992

Arrhythmias during the acute phase of reperfusion therapy for acute myocardial infarction: effects of beta-adrenergic blockade.

In 107 patients with acute myocardial infarction, the incidence of ventricular arrhythmias during the acute phase of thrombolysis was examined by means of Holter monitoring. In patients with a patient infarct-related artery as assessed angiographically at 90 minutes, the occurrence of accelerated idioventricular rhythms was noted significantly more frequently than in patients with a permanent occluded vessel. This arrhythmia peaked in the first 180 minutes after the start of thrombolysis. In addition, single ventricular premature beats and runs of ventricular tachycardia were also more common in patients with successful reperfusion. The effects of acute intravenous administration of beta-blockers were examined in 66 patients without contraindications to this therapeutic approach. There were no differences in the occurrence of any type of rhythm disorders in patients with (n = 43) or without beta-blockade (n = 23). Thus ventricular arrhythmias particularly accelerated idioventricular rhythms, and single ventricular premature beats occur more frequently in patients with a patent infarct artery within the first 24 hours after thrombolysis. Acute intravenous beta-blockade does not appear to exert significant antiarrhythmic effects during this period.

Adrenergic beta-Antagonists↗
PubMed1992

Efficacy and safety of sotalol in patients with complex ventricular arrhythmias.

Sotalol is a unique beta-blocker that prolongs repolarization. Its use in 626 patients with complex ventricular ectopic activity, as reported in the literature, resulted in suppression of arrhythmia in 50 to 60% of treatment attempts. Detailed analysis of data on arrhythmias in 356 patients that were entered prospectively into a database revealed a median reduction in ventricular premature beats of 76%, compared to a median suppression of repetitive ventricular ectopic activity of 91% and of episodes of nonsustained ventricular tachycardia of 97% (p = 0.002 vs reduction of ventricular premature beats). This marked antiarrhythmic potency of sotalol in repetitive ventricular arrhythmias is thought to be due to its class III activity. Drug efficacy was independent of age, sex, the presence or absence of organic heart disease and the degree of sotalol-induced prolongation of corrected QT interval. Evaluation of left ventricular function in 215 patients treated with the drug demonstrated that depression of left ventricular ejection fraction occurred far less frequently than expected with conventional beta-blockers. Even patients with severely depressed pump function tolerated sotalol surprisingly well. There is a propensity of the drug to aggravate arrhythmia, which resulted in serious proarrhythmic events in 30 (3.5%) of 853 patients. These often consisted of torsades de pointes (9 of 30 patients). Proarrhythmia occurred primarily within the first 3 days of dosing, and exhibited a dose-dependence. In conclusion, sotalol is an effective and well-tolerated antiarrhythmic drug in patients with complex ventricular ectopic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Short- and long-term antiarrhythmic and hemodynamic effects of d,l-sotalol in patients with symptomatic ventricular arrhythmias.

The antiarrhythmic and hemodynamic effects of sotalol (160 to 480 mg/day), a beta-blocking agent that prolongs ventricular repolarization, were examined in 38 patients with complex symptomatic ventricular ectopic activity. During ambulatory monitoring, 24 patients (63%) exhibited a reduction of greater than 75% in single ventricular premature beats (VPBs) and greater than 90% reduction in repetitive arrhythmia. In contrast to the effects of other agents, left ventricular ejection fraction as determined by radionuclide angiography was not impaired, increasing slightly from 45 +/- 14% to 47 +/- 14% during therapy (p less than 0.05). Antiarrhythmic drug efficacy did not correlate with baseline ejection fraction or sotalol-induced changes in ventricular function. Late follow-up studies disclosed that antiarrhythmic efficacy and tolerance were maintained in the majority of patients. Repeat radionuclide angiography at 6 months revealed no late drug-induced depression of left ventricular function. Sotalol appears to be an effective and well tolerated agent for treatment of complex ventricular ectopic activity, even in the setting of compromised cardiac function.

Adult↗
PubMed1992

ST segment analysis for assessment of coronary artery patency: comparison of surface ECG and Holter recordings.

In a prospective trial in 124 patients with acute myocardial infarction, Holter and surface ECG recordings were obtained simultaneously and compared for their ability to assess thrombolysis-induced ST segment changes. Accuracy in predicting patency of the infarct-related artery was evaluated in both methods. Success or failure of thrombolysis was determined angiographically 90 min after the start of therapy. For both methods, sensitivity, specificity, and positive predictive value for correct prediction of the perfusion status ranged between 64% and 92%. However, the negative predictive value was considerably lower (40-53%). There were no significant differences in any parameter evaluated for either method. Thus, two surface ECG recordings before and 2 h after the start of therapy yield the same predictive value as continuous Holter monitoring with respect to thrombolysis-induced coronary artery reperfusion. However, for triage of patients to early coronary interventions, more sophisticated methods are needed for non-invasive prediction of coronary artery patency due to the low negative predictive value of ST segment analysis.

Adult↗
PubMed1992

Intraindividual reproducibility of heart rate variability.

Heart rate variability was determined from three consecutive Holter recordings performed on days 1, 7, and 28 in 17 normal subjects, in 13 patients with angiographically normal coronary arteries, and in 9 patients with remote myocardial infarctions. Group data of several time and frequency domain measures of heart rate variability were highly reproducible (correlation coefficients 0.629-0.894). However, some individuals exhibited considerably larger day-to-day variations in heart rate variability. Single heart rate indices differed by up to 50% between two Holter recordings. Such potential differences must be considered when repeated heart rate variability determinations are used to assess changes in neurocardiac reflex regulation or effects of therapeutic interventions.

Chest Pain↗
PubMed1992

Efficacy of intravenously administered amiodarone for short-term control of serious arrhythmias.

Intravenously administered amiodarone exerts substantial antiarrhythmic activity that is based on several different electrophysiologic mechanisms. Of these, the most important consists of an antitachycardic effect together with a significant prolongation of repolarization. The acute intravenous administration of amiodarone has been found to be effective in supraventricular and ventricular tachyarrhythmias resistant to conventional antiarrhythmic agents. Because amiodarone is free of detrimental hemodynamic effects in the majority of patients, intravenous administration of this compound seems to be particularly suitable in patients with serious arrhythmias in the setting of compromised left ventricular function.

Action Potentials↗
PubMed1991

[Anti-arrhythmia drugs in geriatric patients].

Owing to the special pharmacodynamic and pharmacokinetic situation in the aged, the therapeutic spectrum of antiarrhythmic agents is very narrow. The indication for these substances must be established in accordance with strict criteria. Once indicated, antiarrhythmic drug therapy must be initiated at the lowest possible dose, and increases in dosage must be gradual. Non-controlled empirical treatment with such drugs rejected, and the success or lack of success of such treatment must be checked using suitable methods, for example, Holter monitoring. Since the patients often have multiple diseases, particular attention must be paid to interactions with other drugs. Careful consideration must be given to the possibility of Cardiac side effects of antiarrhythmic agents such as proarrhythmic or negative inotropic effects.

Aged↗
PubMed1991

Assessment of coronary artery patency after thrombolytic therapy: accurate prediction utilizing the combined analysis of three noninvasive markers.

The predictability of patency of the infarct-related artery assessed by means of three noninvasive easily obtainable markers was prospectively examined in 82 patients undergoing thrombolysis for their first myocardial infarction. Positive noninvasive markers were defined as follows: 1) early peak creatine kinase (CK) activity less than or equal to 12 h after the start of thrombolysis; 2) greater than or equal to 50% reduction in ST segment elevation; and 3) occurrence of reperfusion arrhythmias within the 1st 90 min of thrombolytic therapy. In 63 (77%) of the 82 patients, Thrombolysis in Myocardial Infarction (TIMI) grade II/III reperfusion was achieved within the 1st 90 min as assessed by coronary angiography. Separate analysis of each marker revealed the following respective values for sensitivity, specificity and positive and negative predictive value regarding prediction of coronary artery patency: CK peak less than or equal to 12 h: 84%, 95%, 98% and 64%; reduction of the ST segment elevation greater than or equal to 50%: 60%, 95%, 97% and 42%; and reperfusion arrhythmias: 63%, 89%, 95% and 43%. The combined analysis of all three markers utilizing a logistic regression procedure showed that CK peak (p = 0.0001) and resolution of the ST segment elevation (p = 0.005), but not the occurrence of reperfusion arrhythmias (p = 0.26), were independent predictors of vessel patency. From this logistic regression procedure, a sensitivity of 100%, a specificity of 90%, a positive predictive value of 97% and a negative predictive value of 100% for prediction of coronary artery patency were obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1991

Calcitriol decreases calcitonin secretion from a human medullary carcinoma cell line via specific receptor action.

Since calcitonin stimulates calcitriol production we examined whether a feedback regulatory mechanism exists between these hormones. First, the calcitriol receptor was localized immunocytochemically in cultured TT cells originating from a human thyroid medullary (C-cell) carcinoma. The receptor was demonstrated by light and electron microscopy in cell nuclei and in small amounts in the cytosol. Receptor levels increased when the cells were cultured at physiological (120-240 pmol/l) or somewhat higher concentrations (1200-2400 pmol/l) of calcitriol. In parallel, the same doses of calcitriol markedly inhibited secretion of calcitonin into the medium. These results indicate a feedback loop between calcitriol and calcitonin.

Calbindins↗
PubMed1990

Immunohistochemical studies on human myocardial mast cells.

Immunoreactivity of resting human heart mast cells [MCs] to a wide variety of antisera was studied in the right atrial auricles and papillary muscles of patients subjected to open heart surgery. All MCs reacted positively to antisera against leukocyte common antigen, vimentin and histamine. Some MCs positively reacted with antisera against lysozyme, alpha 1-antitrypsin, alpha 1-antichymotrypsin, and S-100 protein. Immunostaining pattern was similar in papillary muscle MCs and atrial MCs. There was no reaction with antisera against epithelial, tumor, neuronal, and endocrine cell antigens used in this study. Our studies displayed the existence of differences in immunoreactivity between human neoplastic and reactive MCs and heart resting mast cells. This may reflect the heterogeneity of human MCs from different anatomic sites and/or different pathological processes.

Adolescent↗
PubMed1990

[Copper sulfate allergy with special reference to internal exposure].

Sensitization due to copper has rarely been reported, so far. There is no standard patch test regarding allergy against copper sulphate (CSA). Our study is concerned with the evaluation of data of 10.936 patients patch tested between 1975 and 1985. Since--aside from external exposure--internal exposure to copper sulphate has become increasingly significant, we additionally tested 118 female patients who were or had been wearing intrauterine contraceptives containing copper. Our results showed that CSA is relatively rare and not as often found as sensitization to cobalt or nickel. CSA is rarely monovalent, but usually associated with other metal allergies, especially with nickel and cobalt sensitization. Since we frequently saw toxic reactions to copper sulphate, the skin tests should be performed with 0.5 or 0.01% copper sulphate in water. The test persons with intrauterine contraceptives were not often sensitive either; thus the likelihood of CSA seems to be small in these cases. Individual patients, however, may develop skin eruptions caused by an intrauterine contraceptive containing copper sulphate, as we can prove in one of our patients.

Adolescent↗
PubMed1989

Comparison of twice daily with thrice daily administered encainide for benign or potentially lethal ventricular arrhythmias.

The antiarrhythmic efficacy of encainide administered 2 (group A) or 3 times daily (group B) was evaluated in a randomized, placebo-controlled trial involving 101 patients with benign or potentially malignant ventricular arrhythmias. In group A, encainide was titrated at dosages of 35, 50 and 75 mg twice daily and in group B at dosages of 25, 35 and 50 mg 3 times daily. Drug efficacy, as judged by repeated ambulatory monitoring, was defined as greater than 75% reduction in ventricular premature complexes combined with a greater than 90% abolition of pairs and runs of nonsustained ventricular tachycardia. In group A, 27 of 52 patients (52%) had their arrhythmia suppressed by the drug compared with 34 of 49 (69%) in group B (difference not significant). There was a trend toward better arrhythmia control in group B if a total daily dose of greater than 100 mg was necessary for arrhythmia suppression. Side effects were frequent in both groups (24 vs 28%, difference not significant). Thus, encainide administered twice daily effectively suppresses ventricular arrhythmias in this patient population.

Adult↗
PubMed1989

Immunocytochemical localization of vitamin D-dependent calcium-binding protein (calbindin) in thyroid parafollicular cells of guinea pig.

The presence of the 28K vitamin D-dependent, calcium-binding protein (28K calbindin) was investigated by immunocytochemistry in normal thyroid glands and parathyroid glands of rats, guinea pigs, rabbits and men, as well as in human thyroid medullary carcinomas and human parathyroid adenomas. In addition, thyroid glands and parathyroid glands of rats and guinea pigs were studied after treatment with vitamin D3 injected intramuscularly at a total dose of 1.2 x 10(6) IU per 100 g body weight. 28K calbindin was found exclusively in parafollicular cells of guinea pigs and never in those of other species investigated. It was present predominantly in the cytoplasm and in lower concentration in nuclei. After vitamin D3 treatment, increased immunoreactivity of 28K calbindin was observed in the cytoplasm and, even more pronounced, in the nuclei. In normal parathyroid cells and in parathyroid tumors and medullary thyroid carcinomas, 28K calbindin was not demonstrable. Our findings suggest an important function of calbindin in the cellular calcium processing of parafollicular cells of guinea pigs.

Adenoma↗
PubMed1989

The effect of stress induced experimental gastric ulcers on enterochromaffin cells and on serotonin and 5-hydroxyindolacetic acid levels in stomach and duodenum of the white rat.

In rats subjected to acute or protracted stress of immobilization, gastric and duodenal mucosae were monitored for presence of ulcers and their enterochromaffin cells were examined, identifying them with the use of anti-serotonin antibodies and PAP technique. In parallel, serotonin and 5-hydroxyindolacetic acid levels in the stomach and duodenum were estimated. Ulcers developed only in the stomach and exclusively in stress-unadapted animals. Development of ulcers was paralleled by enterochromaffin cell degranulation, decrease in serotonin levels, and increase in 5-hydroxyindolacetic levels in both the stomach and the duodenum. Significance of the findings for contemporary hypothesis of gastric ulcers' pathogenesis was discussed.

Animals↗