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Biomedical subjects

A Mager

Publications and source records attributed to A Mager.

50 records · Page 3Linked to original sources
PubMed1990

B cells from bovine leukemia virus- (BLV) infected sheep with hematological disorders express the CD5 T cell marker.

Though peripheral blood B cells from healthy sheep were known to be devoid of the CD5 T cell marker, it appears from our study that most B cells from bovine leukemia virus- (BLV) infected sheep with hematological disorders express both the CD5 marker and surface IgM. The possible meaning of this T cell marker expression on B cells from BLV-infected sheep is briefly discussed.

Animals↗
PubMed1989

[Classification of acute myocardial ischemia by electrocardiography].

Electrocardiographic recording during chest pain is usually performed for detection of myocardial ischemia and localization of the affected area. By analyzing changes in electrocardiograms recorded during chest pain, pathophysiological mechanisms of ischemia, prediction of coronary pathology, and the risk of evolution to myocardial infarction can be determined. Myocardial ischemia is caused by either an increase in O2 demand, reduction in coronary flow, or both. The former is manifested by tachycardia and in such patients measures should be taken to slow the heart rate. Patients with ischemia without tachycardia suffer from reduction of coronary flow and therapy should be aimed at increasing flow. We classify patients with ischemia but without tachycardia according to electrocardiographic patterns recorded during chest pain by precordial leads as follows: group 1, those with ST segment elevation and with positive T waves; group 2, ST segment depression and negative T waves; and group 3, ST depression and positive T waves. Group 1 patients have anterior wall ischemia and the left anterior descending artery is usually involved. They are possible candidates for coronary angiography. In group 2, the electrocardiographic changes reflect extensive subendocardial myocardial ischemia. We found severe coronary artery disease (LMCA or right main artery equivalent) in 69% of such patients, and the mortality in those with subsequent myocardial infarction was 77%, mainly due to pump failure. When this latter electrocardiographic pattern is found, intervention should be prompt, and surgery rather than angioplasty is usually necessary. Patients with ischemic ST depression maximal in V2-V3 should not be included in this group since these changes are reciprocal with posterolateral wall ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1989

The head-up tilt table test in patients with syncope of unknown origin.

Forty patients with recurrent syncopal episodes of uncertain etiology were evaluated with a 60-degree head-up tilt table test for 60 minutes. There were 21 men and 19 women, with a mean age of 36 +/- 19 years, a mean of 7.6 syncopal episodes per patient, and a mean duration of symptoms of 4.2 +/- 6 years. Twelve patients had evidence of organic heart disease. Ten control subjects with no history of syncope were studied similarly. Syncope did not occur in any of these controls. Syncope occurred in 15 patients (37.5%) after a mean standing time of 42 +/- 12 minutes. Syncope was due to a typical vasovagal reaction in 11 patients and to hyperventilation in three patients. One last patient fainted without changes in heart rate or blood pressure. In each case, symptoms during the test resembled those previously experienced.

Adolescent↗
PubMed1989

Surgical removal of echocardiographically detected multiple pedunculated and mobile left ventricular thrombi in acute myocardial infarction.

Two-dimensional echocardiography revealed at least three left ventricular mural thrombi in a 59-year-old man with acute anterior myocardial infarction. The thrombi, which had highly mobile pedunculated elements, were attached to the septo-apical wall and protruded into the left ventricular cavity. In spite of the lack of a clinical event but in view of the potential risk of embolization, surgical removal of the thrombi was performed on the 16th day of hospitalization.

Echocardiography↗
PubMed1988

Unstable angina: ST segment depression with positive versus negative T wave deflections--clinical course, ECG evolution, and angiographic correlation.

Thirty-two consecutive patients who initially had horizontal or downward-sloping ST segment depression confined to the precordial leads were studied. Patients were divided into two groups: group A included 21 patients with horizontal or downward-sloping ST depression with peaked positive T waves, and group B comprised 11 patients with peaked negative T waves and downward or horizontal ST depression. The incidence of acute myocardial infarction (AMI) was similar (group A 38.1% vs group B 36.4%; p greater than 0.05). In-hospital mortality was much more significant in group B (p = 0.03). Coronary arteriography was performed in 31 patients. Of the 10 patients in group B who were catheterized, seven (70%) had left main occlusion. Of the 21 patients in group A, none had a significant left main lesion (p = 0.001), although eight (38.1%) had single-vessel disease (p = 0.05). Thus the ECG pattern of horizontal or downward-sloping ST depression passing into a peaked negative T wave identifies a subgroup of high-risk patients in whom the prognosis is poor once AMI occurs. Early catheterization is recommended when this ischemic pattern is apparent on the ECG.

Aged↗
PubMed1988

The natural course of electrocardiographic stages of acute inferior myocardial infarction in regard to R/Q ratio group classification.

Forty-three patients with their first acute inferior wall myocardial infarction (IWMI) were divided into three groups according to the R/Q ratio in standard lead II. This was done to correlate these groups with the characteristic course of electrocardiographic stages. The R/Q ratio was measured on the ninth day of follow-up study, and the electrocardiographic stages were followed from the onset of the IWMI up until the ninth day. Patients with R/Q greater than 2 (group I) had a more rapid progression through the electrocardiographic stages, along with a better clinical course than patients with a lower R/Q ratio. Patients in group III, with R/Q less than 1, had a slower electrocardiographic stage progression, which correlates well with a more complicated clinical course. Group II was an intermediate group in both the electrocardiographic and clinical course. Rapid stage evolution in the first 12 hours of the IWMI was followed by a more rapid progression through stages during the rest of the follow-up period. It is suggested that the R/Q ratio in lead II can be used as a marker of the severity of IWMI, since it correlates well with the course of electrocardiographic stages. The greater the R/Q ratio, the more rapid the progression of electrocardiographic stages, and the better the clinical course. This may be an additional simple and inexpensive electrocardiographic tool for following the natural course of IWMI.

Adult↗
PubMed1988

Repetitive ventricular fibrillation preceded by both ST segment depression and elevation during acute myocardial ischemia.

A patient had repetitive ventricular fibrillation preceded by alternating ST segment depression and elevation. The ECG changes were confined to the precordial leads only, reflecting subendocardial and transmural ischemia, respectively. It is speculated that the patient exhibited consecutive episodes of subtotal and total coronary occlusion, both episodes being critical enough to induce lethal arrhythmias.

Aged↗
PubMed1987

Traumatic internal jugular vein cannulation.

A 63-year-old man with acute myocardial infarction complicated by atrioventricular block underwent an insertion of a temporary electrode for cardiac pacing. The posterior approach for right internal jugular vein cannulation was used. A 15-gauge needle was inserted under the sternocleidomastoid muscle aiming at the suprasternal notch with a 30-degree posterior angle of entry. An hour later the patient started to hiccup. The hiccups were resistant to drug therapy and to cessation of pacing. A chest radiograph revealed elevation of the right diaphragm and hematoma on the right side of the trachea, possibly compressing the right phrenic nerve on its route beneath the sternocleidomastoid muscle and the internal jugular vein. Within seven days the hiccups gradually ceased. Our case shows the advantages and complications of internal jugular vein cannulation.

Catheterization↗
PubMed1987

Effect of metaraminol during acute inferior wall myocardial infarction accompanied by hypotension: preliminary study.

This study was designed to evaluate the effects of metaraminol (Aramine) in six patients with evolving acute inferior wall myocardial infarction accompanied by hypotension and warm limbs. There were 16 episodes of acute inferior wall ischemia, and the response to therapy was judged by evaluating blood pressure and ST segment and T wave abnormalities. Three patients received intravenous isosorbide dinitrate and two received streptokinase as the initial therapy. The mean ST segment elevation was significantly reduced (from 4.94 +/- 1 to 0.5 +/- 0.7 [p less than 0.0001]) after metaraminol infusion was initiated. The average T wave height also decreased (from 6.8 +/- 2 to -1.3 +/- 2.5 mm [p less than 0.0005]). The average heart rate decreased from 82 +/- 11 to 69 +/- 9 beats/min (p less than 0.05) and the mean arterial blood pressure increased from 81 +/- 12 mm Hg before metaraminol treatment to 126 +/- 8 mm Hg after treatment. All these changes occurred within a few minutes after metaraminol therapy was instituted. In 12 episodes, accelerated idioventricular rhythm appeared concomitantly with the resolution of ST segment elevation. Coronary angiography performed between 4 and 10 days after admission demonstrated significant obstruction in all infarct-related arteries, but none was totally occluded. Left ventricular function was normal in three patients and slightly hypokinetic in the inferior wall in two. These results indicate that in a selected group of patients with acute inferior myocardial infarction, metaraminol administration (in certain hemodynamic circumstances) can alleviate acute ischemia within a few minutes and thereby reduce ischemic injury.

Adult↗
PubMed1986

Predominant right ventricular infarction. Clinical and electrocardiographic features.

Based on two-dimensional echocardiographic wall motion abnormalities, 82 patients with acute inferior wall myocardial infarction were divided into 3 groups: group 1. predominant right ventricular infarction-20 patients; group 2. combined right and left ventricular infarction-33 patients; and group 3. predominant left ventricular infarction-29 patients. There were no significant statistical differences between the three groups regarding age, sex, Killip class on admission and jugular venous engorgement. Group 2 patients had higher peak creatine kinase levels and a lower rate of life threatening ventricular arrhythmia than the other groups. On M-mode echo, patients in group 1 had higher RV/LV ratios and lower left ventricular systolic and diastolic dimensions than group 3 patients. On 2-D echo and radionuclear studies, group 1 patients had more right ventricular wall motion abnormalities and minimal left ventricular wall motion disturbances. The left ventricular ejection fraction was higher and the right ventricular ejection fraction lower in group 1 patients than in those groups 2 and 3. The electrocardiogram showed small Q and relatively tall R waves in II, III, AVF in group 1 patients, and deep Q with loss of R waves in patients with combined or exclusive left ventricular infarction (groups 2 and 3). We conclude that predominant right ventricular infarction, which occurs in 24% of inferior wall infarction patients cannot be characterized clinically; however, an electrocardiographic pattern was found to detect this form of infarction with a sensitivity of 80% and a specificity of 70%. Combined left and right ventricular infarction and exclusive left ventricular infarction could be detected electrocardiographically with a sensitivity of 70% and a specificity of only 30%.

Aged↗
PubMed1982

[Magnetic shielded room to measure very low magnetic and electric fields].

An extraordinary magnetically shielded room was designed and constructed for the Physikalisch-Technische Bundesanstalt Institut Berlin to measure extremely weak magnetic fields of the human body with SQUID-magnetometers. The inner and the outer dimensions of the cube-shaped room are 2.25 m and about 5 m. The shield has 6 magnetic shells of a high-permeability alloy and an inner shell welded of massive copper plates. The total weight of the magnetic alloy is about 10 t and about 5 t for the inner copper shell. The required shielding factor of 1000 for the very low frequencies was greatly surpassed by the real measured value of 10000 (measured without any compensating or idealizing method). With rising frequencies the shielding factor reaches higher values, at 50 Hz more than 100000 and a million for 1000 Hz. First measurements in the shielded room with high-resolution magnetocardiograms (HR MCG) and high-resolution electrocardiograms (HR ECG) showed new methods for non-invasive electrophysiological investigations in man.

Electricity↗