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Biomedical subjects

M M Zion

Publications and source records attributed to M M Zion.

At least 19 recordsLinked to original sources
PubMed1994

A prospective randomized trial of intravenous magnesium versus intravenous propranolol in acute myocardial infarction.

A total of 266 patients entered into a study comparing the effect of intravenous magnesium and propranolol following acute myocardial infarction. Of these, 97 were able to receive either drug and were therefore randomized into the magnesium (n = 51) or propranolol group (n = 46). 88 patients were unable to receive propranolol and formed a third group (NR) while a further 81 patients could not receive either drug and formed a fourth group (N). The study showed that intravenous magnesium was as effective in preventing potentially lethal arrhythmias as propranolol and could be given to some 70 per cent of such patients whereas propranolol could only be given to 36 per cent.

Aged↗
PubMed1994

Long-term follow-up after acute myocardial infarction in patients randomized to treatment with intravenous magnesium or intravenous propranolol in the acute phase.

Ninety-five patients with acute myocardial infarction were followed up for 6 months to 3 years (mean 25.4 months) in a preliminary study to compare the effects of intravenous magnesium (49 patients) with that of intravenous propranolol (44 patients) given immediately after admission to the intensive care unit. There were four cardiac deaths in the propranolol group and no deaths in the magnesium group (P < 0.046) and 27 per cent of patients who received propranolol subsequently developed cardiac failure as opposed to 12 per cent of those who had received magnesium (P < 0.04). Intravenous magnesium given in the early stages of myocardial infarction reduces the subsequent cardiac death rate possibly by reducing infarct size.

Aged↗
PubMed1993

Progression and regression of coronary artery disease in one year. Quantitative angiographic assessment in patients with stable angina pectoris.

The rate of progression of coronary artery stenoses (CAS) is not clear. Spontaneous regression may also occur. Seventy-one CAS in 25 patients who were enrolled in a study of the effects of chromium on CAS were analysed. Coronary angiography was performed in multiple views and patients randomised to chromium or placebo treatment. Videodensitometric quantitative analysis was performed using a Vanguard XR70 Analyzer. After 1 year all patients were recatheterised. Corresponding frames from identical views were analysed. CAS were assessed with the observers blinded to the initial study results. No differences were found between chromium or placebo and the results have been combined. There was no overall progression of CAS as assessed by % area stenosis (p = 0.65), % diameter stenosis (p = 0.19), stenotic area (p = 0.87), or stenotic diameter (p = 0.99). However, 20% of individual lesions progressed, while 10% regressed, and 70% remained the same. These changes must be taken into account in studies of interventions which may modify the course of coronary atherosclerosis, and if coronary by-pass surgery is to be performed with a 1 year delay after angiography.

Adult↗
PubMed1992

Reproducibility of measurements of coronary narrowings by videodensitometry and by digital calipers.

Computer-assisted videodensitometry has been shown to be a reliable and reproducible method of measuring absolute and relative coronary narrowings. Using a commercially available analyzer (Vanguard XR70) we confirmed intra- and interobserver reproducibilities in 34 narrowings in 9 patients. Analyses were performed on normal area and diameter, stenotic area and diameter, percent area stenosis and percent diameter stenosis. For all 6 analyses, excellent intra- and interobserver correlations were found (r = 0.93-0.98), with slopes close to 1 and intercepts close to zero. Caliper measurements (Mitutoyo Digimatic) of the same lesions by the same observers showed good inter- and intraobserver reproducibility for percent diameter stenosis (r = 0.90 and 0.86), with mean interobserver difference of 1.67 +/- (SD) 6.4% and intraobserver difference of 2.97 +/- (SD) 7.9%. However, less good correlations were found between caliper and videodensitometric measurements of percent diameter stenosis; r = 0.61 and 0.76 for the two observers. These data suggest that videodensitometry is a highly reproducible quantitative angiographic method, suitable for documenting changes in the severity of coronary artery lesions, both spontaneous or related to interventions. Caliper measurements do not provide the same degree of accuracy, but they have acceptable reproducibility in measuring diameter stenosis. As such, they are also suitable for assessing changes in severity of coronary artery lesions in individual patients.

Angioplasty, Balloon, Coronary↗
PubMed1990

Reproducibility of measurements of coronary narrowings by videodensitometry: unreliability of single view measurements.

Computer-assisted videodensitometry has been shown to be a reliable and reproducible method of measuring absolute and relative coronary narrowings. Using a commercially available analyzer (Vanguard XR70) we confirmed the intra- and interobserver reproducibilities in 34 narrowings in 9 patients. Analyses were performed on normal area and diameter, stenotic area and diameter, percent area stenosis and percent diameter stenosis. For all 6 analyses, excellent intra- and interobserver correlations were found (r = 0.93-0.98), with slopes close to 1 and intercepts close to zero. In a separate study of 16 lesions in 11 patients, each lesion was analyzed in both the RAO and LAO planes. Correlation between the measurements was reasonable with r = 0.76 for the stenotic area and r = 0.75 for the absolute diameter stenosis. However, with suboptimal slopes (0.54 and 0.63 respectively), actual differences between measurements in the two planes were often unacceptably large. These data suggest that videodensitometry is a highly reproducible quantitative angiographic method; however, single view analyses are inadequate for comparative studies.

Absorptiometry, Photon↗
PubMed1990

Use of pulmonary artery catheters in patients with acute myocardial infarction. Analysis of experience in 5,841 patients in the SPRINT Registry. SPRINT Study Group.

This study analyzes the use of PAC in a registry comprising 5,841 hospitalized patients with AMI. A total of 371 patients received PAC. In-hospital mortality was higher in patients with CHF who received PAC, while there was no difference in patients with cardiogenic shock or persistent hypotension. Mortality in patients receiving PAC was higher irrespective of the presence or absence of "pump failure." A separate analysis of discharge summaries of 364 patients with CHF showed that PAC was used more frequently in sicker patients and that when severity of CHF was assessed, no difference in mortality was found in patients with mild or moderate CHF. We conclude that while a higher in-hospital mortality is found in patients receiving PAC, this excess is likely related to difference in severity of CHF, which had not been assessed in every individual. It is unlikely that PAC increases mortality.

Adult↗
PubMed1990

Continuous intravenous infusion of magnesium sulfate after acute myocardial infarction.

Two hundred and fifty patients admitted with acute myocardial infarction were treated with a continuous infusion of magnesium sulfate for 24 h (a total of 46 mmol of elemental magnesium). Only 1 patient had ventricular fibrillation; no patient had sustained ventricular tachycardia requiring cardioversion. Twenty-five patients had short runs of non-sustained ventricular tachycardia and did not need cardioversion. In 6 further patients, the infusion had to be discontinued because of a drop in blood pressure. The in-hospital mortality for the group was 3.4%.

Aged↗
PubMed1989

Acquired obstruction of the ventricular septal defect in tetralogy of Fallot.

The interventricular septal defect in patients with tetralogy of Fallot is, in most cases, a nonrestrictive malalignment type of defect. Rare examples of a restrictive defect have been described. We report a case of tetralogy of Fallot with pulmonic atresia in which the interventricular septal defect was found to be nonrestrictive at birth. The obstruction of the defect developed gradually, until, at the age of 6 years, a gradient of 55 mm Hg across the defect was found at repeat cardiac catheterization. Echocardiography proved that the acquired obstruction was due to excessive tricuspid valve tissue, while Doppler studies suggested a similar gradient between the right ventricle and the ascending aorta. This rare case should alert the clinician to the possibility of an acquired obstruction of the ventricular septal defect, with suprasystemic right ventricular pressure, in cases of tetralogy of Fallot, even if an early study suggested a nonobstructive defect. The diagnosis of this situation is of importance because of the poor prognosis which it carries.

Cardiac Catheterization↗
PubMed1988

Lymphocyte potassium and magnesium concentrations as prognostic factors after acute myocardial infarction.

215 patients admitted with acute myocardial infarction were prospectively evaluated for prognostic factors. When lymphocyte potassium concentration increased by up to twofold of normal, a high lymphocyte magnesium concentration was associated with a good prognosis. However, when the increase in lymphocyte potassium concentration was greater than twofold, the presence of a high lymphocyte magnesium made no difference to mortality. Age, the female sex, anterior wall infarction, high serum enzymes, heart failure, diabetes mellitus in females and serious arrhythmias were all bad prognostic signs.

Aged↗
PubMed1988

Recurrent ventricular tachycardia in hypothyroidism--report of a case and review of the literature.

A 47-year-old woman suffered from recurrent attacks of ventricular tachycardia. Her electrocardiogram showed low voltage, right bundle branch block and prolonged QT interval. Hormonal studies disclosed primary hypothyroidism. The arrhythmia responded to treatment with procainamide and did not recur following thyroid replacement therapy. The QT interval returned to normal. Five similar cases reported in the literature are reviewed, emphasizing the importance of QT prolongation, in the context of hypothyroidism, as a risk factor for the occurrence of ventricular tachycardia.

Electrocardiography↗
PubMed1988

Effects of enalapril on lymphocyte sodium, potassium, magnesium and calcium levels in patients with severe congestive heart failure.

Fifteen patients (median age 73 years) with severe congestive heart failure were treated with Enalapril for a total of 12 weeks with a significant improvement in their right atrial pressures and in their functional state. Renal function, serum potassium, magnesium and calcium levels were unchanged. Lymphocyte sodium, potassium and calcium levels were generally lower than control values throughout the study but these differences were only statistically significant early in the study. Lymphocyte magnesium levels were unchanged. These findings are in contrast to those previously reported in the literature for such patients treated with conventional diuretics.

Aged↗
PubMed1987

Magnesium in the prevention of lethal arrhythmias in acute myocardial infarction.

Seven of 48 patients (14.6%) with acute myocardial infarction who were given 2.4 g of magnesium sulfate as a single intravenous dose had potentially lethal arrhythmias during the first 24 hours after admission, whereas 16 (34.8%) of 46 patients receiving placebo had similar arrhythmias. In addition, 14 of these 16 patients in the placebo group had their first arrhythmia (in the intensive coronary-care unit) within two hours after the start of the study, whereas in the magnesium-treated group, there were no such arrhythmias until some four hours later. The higher the lymphocyte potassium concentration, the greater the reduction in the incidence of arrhythmias. Serum magnesium levels increased by 16.5% and lymphocyte magnesium concentrations by 72% in the magnesium treated group. Intravenous magnesium reduces the incidence of serious arrhythmias after acute myocardial infarction.

Aged↗