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Biomedical subjects

M G Adams

Publications and source records attributed to M G Adams.

25 records · Page 2Linked to original sources
PubMed1996

ST segment monitoring with a derived 12-lead electrocardiogram is superior to routine cardiac care unit monitoring.

BACKGROUND: Prior studies have shown that a derived 12-lead electrocardiogram with a simple electrode configuration is comparable with the standard electrocardiogram for arrhythmia analysis. METHODS: A prospective, comparative, within subjects design was used to compare the value of the derived 12-lead electrocardiogram with that of routine monitoring of leads V1 and II for detection of transient myocardial ischemia in 250 patients treated for unstable angina or myocardial infarction. RESULTS: During 11,532 hours of derived 12-lead ST segment monitoring, 55 (22%) of 250 patients had 176 episodes of ischemia. Of the 55 patients with ischemia, 75% reported no chest pain and 64% had no ischemic ST changes with routine monitoring leads. All five patients who developed angiographically confirmed abrupt reocclusion after percutaneous transluminal coronary angioplasty had ischemic ST changes with the derived electrocardiogram (sensitivity, 100%), compared with only two patients with routine monitoring (sensitivity, 40%). Serious complications occurred in 17% of angina patients with ischemic events compared to 3% of those without ischemia. Length of stay in the cardiac care unit was twice as long in angina patients who had ischemic events. In patients with acute myocardial infarction, ischemic events were not associated with a more complicated hospital course; however, length of stay in the cardiac care unit was longer in patients with recurrent ischemia. CONCLUSIONS: The findings show that derived 12-lead ST monitoring is superior to routine monitoring of leads V1 and II for detecting transient myocardial ischemia. ST monitoring of the derived 12-lead electrocardiogram may identify high-risk patients with unstable angina and provide prognostic information that would not be otherwise available from the usual clinical measures.

Adult↗
PubMed1996

ST segment deviation during myocardial ischemia: are there gender differences?

UNLABELLED: Prior research indicates that women have greater ST segment shifts at the time of percutaneous transluminal coronary angioplasty (PTCA) balloon inflation than men. However, ST deviation in men and women has not been compared during balloon occlusion of the same coronary vessel. METHODS: To determine whether there is a gender difference in degree of ST deviation, 12-lead electrocardiographic (ECG) recordings were made in 45 subjects undergoing PTCA (25 men, 20 women). A total ST score was obtained by summing absolute deviations across all 12 leads. All patients had single vessel coronary artery lesions in the proximal half of one of the major epicardial arteries without evidence of collateral circulation. RESULTS: There were no differences between men and women in terms of age, left ventricular hypertrophy, ejection fraction, or the Norris Coronary Prognostic Index, which combines age, history of infarction, and evidence of heart failure on chest X-ray. When comparing mean ST segment deviation in men and women, vessel to vessel, no gender differences were found. CONCLUSION: When matched for coronary vessel, men and women have comparable ST deviation patterns during coronary occlusion with PTCA balloon inflation. Therefore, detection of myocardial ischemia related to coronary occlusion with continuous ST segment monitoring should be equally sensitive in men and women.

Adult↗
PubMed1994

Severe hypophosphataemia in anorexia nervosa.

In addition to well-described acid-base and electrolyte disturbances, anorexia nervosa may be complicated by severe hypophosphataemia. We report a case of anorexia nervosa complicated by life-threatening hypophosphataemia manifesting as generalized muscle weakness and bulbar muscle dysfunction, resulting in an aspiration pneumonia and cardiorespiratory arrest.

Adult↗
PubMed1981

Fat accumulation in the rat heart during fasting.

Following a short period of fasting, with free access to water, lipid droplet accumulation (LDA) occurs in many glandular organs as well as in the heart of several species. The present work describes the changes in the hearts of male and female rats of different ages (6, 12, 18 and 24 weeks) deprived of food for 1, 2 and 3 days. LDA was demonstrated by staining with Oil Red O and a special "scoring" system was developed based on sections arbitrarily divided into five regions for each ventricle and two for each atrium. Three standard sections were studied from each heart. This system largely avoided problems arising from the uneven distribution of fats in different parts of the heart. In control animals very little fat was seen in any part of the heart. The pattern of changes was similar in males and females but the degree of LDA was usually much greater in the male. In both sexes LDA increased after 1 day and usually reached a peak by the second day, followed by a sharp decrease, returning to almost normal. However in both sexes the response in the 18-week-old animals was minimal, with no clear peak. The LDA was always maximal in the R ventricle, followed by the L ventricle. The heaviest deposition occurred in the superior parts of the ventricles, close to the atria. LDA was comparatively rare in the atria. Fat appeared to be retained longest in the most heavily loaded regions. Recovery from LDA was rapid, being almost complete 24 hr after returning to a normal diet. Again the most heavily loaded regions retained fat longest. These findings are discussed in related to possible anatomical factors such as the distribution of blood vessels. It is unlikely that such factors offer an adequate explanation abd it is suggested that since the uptake of fats into the heart is probably controlled by lipoprotein lipase the distribution of this enzyme in difference parts of the heart should be investigated. The histochemical changes are also discussed in relation to previous biochemical work. Finally it is pointed out that it is common procedure to fast experimental animals overnight and even such a brief period could bring about considerable histological and metabolic changes.

Age Factors↗
PubMedDate not supplied

Frequency of silent myocardial ischemia with 12-lead ST segment monitoring in the coronary care unit: are there sex-related differences?

BACKGROUND: Ischemia that occurs in the coronary care unit (CCU), whether symptomatic or silent, is associated with significant in-hospital and out-of-hospital complications. Studies have reported that more than 90% of ischemic episodes are silent in patients with unstable angina who are treated in the CCU with maximal medical therapy. Prior reports indicate that women complained more frequently of chest pain than men did. PURPOSE: The aim of this study was to compare the frequency of silent myocardial ischemia in men versus women with use of continuous 12-lead ST segment monitoring in the CCU. A secondary goal was to determine whether silent ischemia was associated with less ST segment deviation as compared with symptomatic ischemia. METHOD: Patients admitted for treatment of acute coronary syndrome in the CCU and who subsequently had 1 or more ischemic events during their monitoring period were selected for this analysis. All patients were continuously monitored (42.5 hours +/- 37.6) in the CCU with the EASI (Zymed Medical Instruments, Camarillo, Calif) 12-lead electrocardiogram (ECG) system that derives 12 leads with use of 3 information channels and 5 electrodes. RESULTS: Of 491 patients, 128 (91 men and 37 women) had at least 1 episode of transient myocardial ischemia. Men and women did not differ in their proportion of chest pain during ischemia (men 27% and women 21%, NS). For both men and women, ST segment deviation was significantly greater during symptomatic ischemia compared with silent ischemia. CONCLUSION: There are no sex-related differences in ischemic events in the CCU in regards to the variables of chest pain and ST magnitude. Therefore, because chest pain is not a reliable indicator of myocardial ischemia in the CCU, regardless of sex, patients should be adequately monitored for ischemic events.

Aged↗