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Biomedical subjects

A M Hutter

Publications and source records attributed to A M Hutter.

At least 37 records · Page 2Linked to original sources

Prognostic utility of predischarge dipyridamole-thallium imaging compared to predischarge submaximal exercise electrocardiography and maximal exercise thallium imaging after uncomplicated acute myocardial infarction.

The prognostic value of predischarge dipyridamole-thallium scanning after uncomplicated myocardial infarction was determined by comparison with submaximal exercise electrocardiography and 6-week maximal exercise thallium imaging and by correlation with clinical events. Two endpoints were defined: cardiac events and severe ischemic potential. Of the 40 patients studied, 8 had cardiac events within 6 months (1 died, 3 had myocardial infarction and 4 had unstable angina requiring hospitalization). The finding of any redistribution on dipyridamole-thallium scanning was common (77%) in these patients and had poor specificity (29%). Redistribution outside of the infarct zone, however, had equivalent sensitivity (63%) and better specificity (75%) for events (p less than 0.05). Both predischarge dipyridamole-thallium and submaximal exercise electrocardiography identified 5 of the 8 events (p = 0.04 and 0.07, respectively). The negative predictive accuracy for events for both dipyridamole-thallium and submaximal exercise electrocardiography was 88%. In addition to the 8 patients with events, 16 other patients had severe ischemic potential (6 had coronary bypass surgery, 1 had inoperable 3-vessel disease and 9 had markedly abnormal 6-week maximal exercise tests). Predischarge dipyridamole-thallium and submaximal exercise testing also identified 8 and 7 of these 16 patients with severe ischemic potential, respectively. Six of the 8 cardiac events occurred before 6-week follow-up. A maximal exercise thallium test at 6 weeks identified 1 of the 2 additional events within 6 months correctly. Thallium redistribution after dipyridamole in coronary territories outside the infarct zone is a sensitive and specific predictor of subsequent cardiac events and identifies patients with severe ischemic potential.(ABSTRACT TRUNCATED AT 250 WORDS)

Dipyridamole↗

Continuous monitoring of left ventricular function by an ambulatory radionuclide detector in patients with coronary artery disease.

Global left ventricular function and a modified V5 electrocardiographic (ECG) lead were continuously monitored by a radionuclide recorder in 12 normal subjects and 39 patients with coronary artery disease while the subjects were performing various daily activities. The ambulatory studies revealed that walking on a level surface caused 11 of 12 normal subjects and 18 of 32 patients to increase their left ventricular ejection fraction by greater than 6% units. A transient decrease in left ventricular ejection fraction (6 to 18%) lasting greater than or equal to 1 min was observed on 36 occasions in 16 patients with coronary artery disease; 12 episodes were accompanied by chest pain or shortness of breath and 24 were asymptomatic. Electrocardiographic ST segment depression suggestive of ischemia was recorded in 6 of the 12 symptomatic and 5 of the 24 asymptomatic episodes. In 10 of the 12 symptomatic episodes, left ventricular ejection fraction began to decrease 30 to 90 s before the onset of symptoms. These studies suggest that continuous monitoring of both left ventricular function and the ECG may permit stratification of episodes of ST depression suggesting ischemia by the degree of left ventricular dysfunction they produce.

Activities of Daily Living↗

Underestimation of prosthetic mitral valve areas: role of transseptal catheterization in avoiding unnecessary repeat mitral valve surgery.

In patients with symptoms of heart failure after mitral valve replacement, identification of a stenosed prosthesis may be difficult. Twelve such patients were evaluated, presenting at a mean of 8.4 years after mitral valve replacement (four mechanical, eight porcine). Transvalvular pressure gradients were obtained using both indirect (pulmonary capillary wedge) and direct (transseptal catheterization) measurements of left atrial pressure. In all 12 patients, the diastolic gradient across the prosthetic valve was overestimated when pulmonary wedge rather than transseptal measurements were used. Calculated mitral valve prosthetic area was underestimated by the pulmonary wedge determinations. These findings may be caused by either the phase delay of the pulmonary wedge V wave relative to the transseptal V wave, resulting in a higher diastolic mean left atrial pressure, or the faulty wedge determinations in the setting of pulmonary hypertension, or both. In patients being considered for repeat mitral valve replacement because of prosthetic valve stenosis, transseptal catheterization allows for more accurate determination of prosthetic valve area and more accurately defines the need for repeat mitral valve surgery.

Aged↗

Anticoagulation in valvular heart disease preoperatively and postoperatively.

We have reviewed the risks and benefits of anticoagulation for cardiac valve disease before and after valve surgery. Though the absence of standardized reporting of complications and the paucity of well-designed comparative studies mandate careful consideration of the variables of individual cases, we have made the following general recommendations: Unoperated patients with rheumatic mitral valvular disease and atrial fibrillation should be chronically treated with warfarin, regardless of the hemodynamic severity of their valvular lesion. The presence of right- or left-sided heart failure is an indication for warfarin treatment, in the absence of significant contraindications. There is emerging evidence that platelet-suppressant therapy may be of benefit in diminishing the thromboembolic risk of at least a subset of patients with rheumatic valvular disease and decreased platelet survival. Until platelet-survival studies are more readily available and larger-scale studies can be performed, however, we do not recommend routine treatment with platelet-active agents. We recommend chronic warfarin anticoagulation in all patients with mechanical prostheses in either the aortic or mitral position, regardless of cardiac rhythm or prosthesis model. We do not routinely add platelet-active agents except in the case of embolism despite adequate anticoagulation with warfarin. Patients with aortic bioprostheses generally do not require warfarin treatment for more than 3 months following valve replacement. The presence of atrial fibrillation and marked depression of postoperative ventricular function are indications for chronic anticoagulation. In the case of mitral bioprostheses, we recommend indefinite warfarin treatment for patients with atrial fibrillation, depressed ventricular function, or low cardiac output. We consider a preoperative history of embolism or an operative finding of left atrial thrombus to be an additional indication for anticoagulation, in the absence of significant contraindications. Patients on anticoagulant therapy should be followed closely--when possible in specialized anticoagulation clinics--to minimize the risks of treatment. Specific recommendations are made for management of anticoagulation during infective endocarditis, pregnancy, and noncardiac surgery.

Anticoagulants↗

Exercise testing in asymptomatic or minimally symptomatic aortic regurgitation: relationship of left ventricular ejection fraction to left ventricular filling pressure during exercise.

Exercise radionuclide angiography is being used to evaluate left ventricular function in patients with aortic regurgitation. Ejection fraction is the most common variable analyzed. To better understand the rest and exercise ejection fraction in this setting, 20 patients with asymptomatic or minimally symptomatic severe aortic regurgitation were studied. All underwent simultaneous supine exercise radionuclide angiography and pulmonary gas exchange measurement and underwent rest and exercise measurement of pulmonary artery wedge pressure (PAWP) during cardiac catheterization. Eight patients had a peak exercise PAWP less than 15 mm Hg (group 1) and 12 had a peak exercise PAWP greater than or equal to 15 mm Hg (group 2). Group 1 patients were younger and more were in New York Heart Association class I. Group 1 patients also had a higher mean rest ejection fraction (0.64 +/- 0.08 vs 0.49 +/- 0.13, p less than 0.01, higher exercise ejection fraction (0.63 +/- 0.10 vs 0.40 +/- 0.18, p less than 0.01), lower end-systolic volume (38 +/- 13 vs 79 +/- 36 ml/m2, p less than 0.01) and higher peak oxygen uptake (24.9 +/- 5.1 vs 16.6 +/- 4.9 ml/kg/min, p less than 0.01) than group 2 patients. However, the two groups had similar cardiothoracic ratios, changes in ejection fractions with exercise, and rest and exercise regurgitant indexes. Using multiple regression analysis, the best correlate of the exercise PAWP was peak oxygen uptake (r = -0.78, p less than 0.01). No other measurement added significantly to the regression. When peak oxygen uptake was excluded, rest and exercise ejection fraction also correlated significantly (r = -0.62 and r = -0.60, respectively, p less than 0.01). Patients with asymptomatic or minimally symptomatic severe aortic regurgitation have a wide spectrum of cardiac performance in terms of the PAWP during exercise. The absolute rest and exercise ejection fraction and the level of exercise achieved are noninvasive variables that correlate with exercise PAWP in aortic regurgitation, but the change in ejection fraction with exercise by itself is not.

Adolescent↗

Contrast-medium-induced electrocardiographic abnormalities: comparison of bolus and infusion of methylglucamine iodamide and methylglucamine/sodium diatrizoate.

A double-blind study comparing electrocardiographic (ECG) abnormalities induced by methyglucamine iodamide and methylglucamine/sodium diatrizoate was conducted in 189 patients. The media were each administered by both bolus and infusion. Iodamide caused fewer ECG changes both by injection and infusion. This contrast medium also resulted in fewer ECG changes in the patient groups with known prior ECG abnormalities, cardiovascular disease, arrhythmias, ischemia, or renal impairment and in those over 50 years of age. Digitalis did not increase the frequency of ECG abnormalities with either medium. With diatrizoate, the lower bolus dose produced as many major ECG changes in the presence of preexisting ECG abnormalities (arrhythmias, ischemia) or prior cardiovascular disease as the three-times-larger infusion dose more slowly administered; conversely, the opposite was found when renal insufficiency or older age existed. The conclusion is that iodamide media caused fewer ECG abnormalities and may be less hazardous.

Arrhythmias, Cardiac↗

The association of clinical, psychosocial, and angiographic variables with work status in patients with coronary artery disease.

The bearing of clinical history, epidemiological risk factors, psychosocial factors, angiographic findings, and treatment characteristics was studied in relationship to the work status of 182 men who underwent coronary angiography because of presumptive coronary artery disease. Follow-up at one year found 42% of the cohort persistently unemployed or working at a lower level, 40% at the same job, and 19% at a more demanding job. Multiple regression analysis was used to derive the most important variables predictive of work status. Neither number of vessels diseased nor Coronary Artery Bypass Graft surgery entered the multiple regression analysis. Instead, the most important variables, listed in decreasing order of importance, are: age, subsequent cardiac morbid events, past myocardial infarction, and mood during the follow-up year. Together, they account for 24% of the variance in work status outcome (p less than 0.001).

Angina Pectoris↗

Early discharge following acute myocardial infarction. Long-term follow-up of randomized patients.

Long-term follow-up was obtained on 138 patients who participated in a prospective, randomized study comparing two weeks with three weeks of hospitalization following uncomplicated acute myocardial infarction. Follow-up information was available on 123 (89%) of all randomized patients. The mean follow-up period was 35 months for those patients who died and 99 months for those who survived. No differences were found between the two groups with respect to survival, cardiac-related deaths, frequency or severity of angina pectoris, subsequent myocardial infarction, incidence of congestive heart failure, number of ventricular aneurysms, or subsequent medical therapy. A significantly greater number of survivors in both groups stopped smoking and had a normal initial heart size than those who died. This long-term follow-up study further supports the conclusions of earlier short-term studies that two weeks of hospitalization is safe in patients with uncomplicated acute myocardial infarction.

Adult↗

Prospective study of medical and urgent surgical therapy in randomizable patients with unstable angina pectoris: results of in-hospital and chronic mortality and morbidity.

At the Massachusetts General Hospital, all 190 patients who presented with the clinical and ECG criteria of the national Unstable Angina Pectoris Study (NUAPS) for unstable angina pectoris (UAP) were prospectively evaluated from their entrance between 1972 and 1976 (the entry period for NUAPS). Coronary angiography was performed in 166 patients. Of these, 83 patients (50%) were not eligible for randomization because of obstruction in the left main coronary artery (4%), inoperable diffuse coronary disease (11%), failure of initial medical therapy (20%), minimal coronary disease (13%), or other reasons (2%). The other 83 patients (50%) were eligible for randomization by NUAPS criteria; 39 received medical therapy and 44 underwent urgent coronary artery bypass surgery (CABG). The medical and surgical patients were comparable in terms of clinical characteristics and extent of anatomical disease. In-hospital (3% medical and 2% surgical) and late (5% medical and 5% surgical) mortality were similar over a mean follow-up period of 46 months. Myocardial infarction rate was statistically similar in-hospital (5% medical and 11% surgical) and during chronic evaluation (5% medical and 14% surgical). However, late severe angina (NYHA class III or IV) occurred in a significantly higher percentage of medical patients (28% medical versus 9% surgical; p less than 0.05) and nine medical patients (23%) required late elective CABG for relief of persistent angina. This experience is comparable to NUAPS, and supports the conclusion that acute management of unstable angina pectoris may begin with intensive medical treatment followed later by more elective CABG for those patients with persistent angina despite medical therapy.

Angina Pectoris↗

Nontransmural myocardial infarction: a comparison of hospital and late clinical course of patients with that of matched patients with transmural anterior and transmural inferior myocardial infarction.

The hospital and long-term course of 67 patients with nontransmural myocardial infarction was compared with that of 66 patients with transmural anterior and 63 patients with transmural inferior infarction matched for age, sex, previous infarction and prior congestive heart failure. During their hospital stay, patients with nontransmural infarction had significantly less congestive heart failure and fewer intraventricular conduction defects than did patients with transmural anterior infarction; fewer atrial tachyarrhythmias and less sinus bradycardia and atrioventricular block than did patients with transmural inferior infarction; and an incidence of hypotension, pericarditis and ventricular irritability similar to that of patients in the other two groups. Patients with nontransmural infarction had a significantly lower coronary care unit mortality rate (9 percent) than that of patients with transmural anterior or transmural inferior infarction (20 and 19 percent, respectively). By 3 months, the mortality rate had risen to 14 percent in patients with nontransmural infarction, but was significantly higher (29 and 27 percent, respectively) in patients with transmural anterior or transmural inferior infarction. Angina was common in all three groups, occurring in more than 50 percent of patients during a mean follow-up period of 28.6 months after hospital discharge. In contrast, the incidence of subsequent myocardial infarction was significantly greater in patients with nontransmural myocardial infarction, occurring in 21 percent at 9 months compared with only 3 percent of patients with transmural anterior (p less than 0.01) and 2 percent of patients with transmural inferior (p less than 0.05) infarction. By 54 months, 57 percent of patients with nontransmural infarction had sustained a new infarction contrasted with only 12 percent of patients with transmural anterior (p less than 0.001) and 22 percent of patients with transmural inferior (p less than 0.01) infarction. Late mortality increased in patients with nontransmural myocardial infarction and, although this group had a significantly better survival rate at 3 months, the overall late mortality of the three groups was comparable. The study suggests that nontransmural myocardial infarction is an unstable ischemic event associated with a great risk of later myocardial infarction and high late mortality rate. A more aggressive diagnostic and therapeutic approach may be warranted in patients with nontransmural myocardial infarction.

Arrhythmias, Cardiac↗

Predicting cardiac morbidity based on risk factors and coronary angiographic findings.

A cohort of 189 men was followed up for 1 year after performance of coronary angiography and determination of risk factors to ascertain which risk factors or clinical and laboratory findings could aid in predicting the patients who would have a substantial cardiac morbid event. Data on clinical signs and symptoms, psychosocial assessments, angiographic findings and presence of standard risk factors for coronary artery disease were collected in each case. Twenty-five percent of the men experienced a substantial cardiac morbid event (hospitalization, myocardial infarction, resuscitation or death). With or without inclusion of the patients who underwent surgery, discriminant analysis equations were successful in predicting morbidity on the basis of risk factor data. For the whole sample such analysis was significant at p < 0.00005 and accurately predicting the fate of 78 percent of the subjects. With exclusion of the surgically treated patients, the discriminant analysis accurately predicted future morbidity 83 percent of the time (p < 0.0001). The following risk factors for increased morbidity were common to both analyses: severity of angina, history of myocardial infarction, family history of heart disease, fatigue and absence of type A behavior.

Adolescent↗