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Biomedical subjects

M I Dunn

Publications and source records attributed to M I Dunn.

At least 19 recordsLinked to original sources
PubMed1995

Postinfarction ventricular aneurysms.

Ventricular aneurysms are circumscribed, thin-walled fibrous, noncontractile outpouchings of the ventricle. The majority are apically located, true aneurysms of the left ventricle (LV) that occur as a consequence of transmural myocardial infarction (MI). The precursor of aneurysm formation appears to be infarct expansion early after acute MI and occurrence generally relates to infarct size. The presence of underlying hypertension and the use of steroids and nonsteroidal antiinflammatory agents may promote aneurysm formation. The clinical sequelae include congestive heart failure (CHF), thromboembolism, angina pectoris, and ventricular tachyarrhythmias. Late rupture is a particular complication of false aneurysms in which the pericardium is the aneurysm wall. The diagnosis may be suspected by the clinical finding of a diffuse, pansystolic apical thrust, persistent ST-segment elevation on the electrocardiogram, and distortion of the cardiac silhouette on chest x-ray. This can be confirmed using echocardiography, radionuclide ventriculography, and cardiac catheterization. The latter has the additional advantage of being able to delineate the coronary anatomy. Management involves prevention, specific therapy for the various clinical manifestations, and surgery. Therapeutic interventions with thrombolytic agents, aspirin, heparin, and beta blockers that are applied early in the evolution of an MI may limit infarction size, thereby reducing the tendency toward infarct expansion and aneurysm formation. Patients with mild CHF can usually be controlled with the standard combination of angiotensin-converting enzyme inhibitors, diuretics, and digoxin. Thromboembolism is best prevented by anticoagulation with warfarin for at least 3 months after the acute MI. The choice of pharmacotherapy for ventricular tachyarrhythmias should be guided by electrophysiologic studies. The treatment of patients with angina pectoris utilizes conventional therapeutic modalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Heart Aneurysm↗
PubMed1995

'Vampire syndrome': serum protein and lipid abnormalities related to frequent sale of plasma.

The sale of plasma for profit has become a common occurrence. In the United States, a healthy individual can donate as frequently as six times per month and up to 60 L of plasma per year. Although plasma donors are generally healthy, intervening conditions can increase the catabolism or decrease the synthesis of certain serum constituents and thereby produce a confusing clinical picture. In 1 month, we encountered two patients who presented with hypoalbuminemia and hypocholesterolemia for which there was no obvious cause except a history of frequent plasma sales.

Adult↗
PubMed1991

Phenytoin hypersensitivity syndrome: a case report.

We report a life-threatening case of phenytoin hypersensitivity syndrome, a rare reaction primarily characterized by fever, skin eruptions, lymphadenopathy, eosinophilia, and hepatotoxicity. The reaction developed in a 27-year-old black man with surgically corrected tetralogy of Fallot who was treated with phenytoin for one month for exercise-induced sustained ventricular tachycardia. Phenytoin therapy was discontinued and the patient was treated with intravenous methylprednisolone; the therapy was later converted to oral prednisone. Clinical improvement was noted five days after admission and the patient was discharged on hospital day 14. This adverse reaction usually develops within six weeks of starting phenytoin therapy and may be fatal in up to 40 percent of the patients who develop hepatotoxicity. Early recognition of this relatively rare reaction is essential to prevent serious and potentially fatal complications.

Adult↗
PubMed1991

Low-intensity anticoagulation in mechanical cardiac prosthetic valves.

Retrospectively, we reviewed the charts of 101 patients at the University of Kansas Medical Center who received low-intensity anticoagulation for mechanical prosthetic valves implanted over a 17-yr period. The mean duration of follow-up was 4.6 yr, and the total duration of follow-up was 466.5 patient-yr. The patients' records were evaluated for evidence of hemorrhagic or thromboembolic complications. A prothrombin time ratio of 1.3 to 1.5 times control was considered to be low-intensity anticoagulation. There were three thromboembolic events or 2.9/100 patient-yr of follow-up at a prothrombin time ratio of less than 1.3, four thromboembolic events or 2.5/100 patient-yr of follow-up at 1.3 to 1.5 times control, four thromboembolic events or 2.2/100 patient-yr of follow-up at 1.6 to 2.0 times control, and no thromboembolic events at prothrombin time ratios greater than 2.0 times control. Hemorrhagic events occurred in three patients at a prothrombin time ratio of less than 1.3 times control or 2.8/100 patient-yr of follow-up, in six patients at 1.3 to 1.5 times control or 3.8/100 patient-yr of follow-up, in ten patients at 1.6 to 2.0 times control or 5.5/100 patient-yr of followup, and in two patients at 2.1 to 2.5 times control or 12.2/100 patient-yr of follow-up. The rate of hemorrhagic events at 2.5 times control was 470/100 patient-yr follow-up. While not providing definitive proof, we believe that our retrospective study provides supportive evidence for the use of low-intensity anticoagulation in patients with mechanical cardiac prostheses.

Adult↗
PubMed1990

Primary pulmonary hypertension in adults.

Primary pulmonary hypertension is an enigmatic disease found predominantly in young women, but it also affects a significant number of middle-aged and elderly males and females. Its onset, characterized by progressively worsening dyspnea, fatigue, and chest pain, is insidious. Three distinct histopathologic subtypes have been identified, and the natural history of the disease process has been well-defined. Pharmacologic treatment options have, in general, been disappointing, and it appears that heart-lung transplantation will be applied only to a small minority of young patients with primary pulmonary hypertension in the near future. We review the histopathology, evaluation, treatment, and prognosis of primary pulmonary hypertension.

Adult↗
PubMed1990

Chest pain.

The accurate diagnosis of chest pain is often difficult. We review the differential diagnosis of chest pain and the diagnostic studies used in the evaluation of chest pain syndromes. Myocardial ischemia, aortic dissection, pulmonary embolism, pericarditis, and gastroenterologic sources of chest pain are the most common. The chest X-ray, electrocardiogram, echocardiogram, heart catheterization studies, and esophageal studies are helpful diagnostically.

Aortic Dissection↗
PubMed1990

The significance of eosinophils in mild and moderate acute cardiac allograft rejection.

The presence of eosinophils has previously been associated with severe acute cardiac allograft rejection. This appears to be a relatively uncommon finding, judging from our experience and the paucity of information appearing in literature. We report three cases where a prominent infiltrate of eosinophils was noted on endomyocardial biopsy following cardiac transplantation. There was no evidence of severe acute rejection in any of these three patients, and one patient had only mild acute rejection without even focal myocardial necrosis. An infiltrate, which includes eosinophils, does not appear to be restricted to severe acute cardiac allograft rejection. Therefore, when eosinophils are noted in endomyocardial biopsy specimens, decisions to revise the immunosuppressive regimen of cardiac transplant recipients should continue to be based upon established conventional histologic criteria.

Acute Disease↗
PubMed1989

Noninvasive assessment of myocardial dysfunction in patients with chronic aortic regurgitation.

Chronic aortic regurgitation may have minimal symptoms until severe myocardial dysfunction is apparent. Multiple preoperative indicators of postoperative prognosis have been sought. It appears that an elevated left ventricular end systolic dimension on echocardiography or elevated end systolic volume on radionuclide ventriculography in combination with depressed LV function and substantially increased calculated systolic wall stress may present an indicator for aortic valve replacement. Response of ejection fraction to stress may not be as reproducible, but when combined with a depressed resting ejection fraction may also be an indicator for aortic valve replacement. Even patients with severely depressed left ventricular ejection fraction may improve with surgery; however, the risks of a poor postoperative outcome is substantial increased. Appropriate management of a patient with chronic aortic regurgitation requires monitoring of multiple parameters during the patient's clinical course for optimal timing of valve replacement surgery.

Aortic Valve Insufficiency↗
PubMed1988

Efficacy and safety of guanadrel in elderly hypertensive patients.

Hypertension is common in the elderly and is associated with higher morbidity and mortality, which may be decreased by effective blood pressure control. Many antihypertensive drugs, however, are not well tolerated by the aged. We treated 21 patients (ten men and 11 women) between ages 65 and 84 years (mean, 73.6 years) with guanadrel sulfate. All patients had received prior antihypertensive therapy, which either was ineffective or caused undesirable side effects. Average follow-up time was 17 months. Mean systolic pressure on enrollment was 188 +/- 17 mm Hg and mean diastolic pressure was 100 +/- 10 mm Hg. After treatment, the mean systolic pressure was 139 +/- 15 mm Hg and mean diastolic pressure was 82 +/- 8 mm Hg. Dosage varied from 5 to 30 mg/d with a mean of 16 mg/d. The only significant side effects were fatigue, dizziness, and dyspnea reported in four patients. Eleven patients took the medication as monotherapy and ten received diuretics or diuretics and beta-blockers as additional therapy. Our conclusion is that guanadrel is an effective, well-tolerated medication for treatment of hypertension in the elderly.

Aged↗
PubMed1987

Breathing pattern abnormalities and arterial oxygen desaturation during sleep in the congestive heart failure syndrome. Improvement following medical therapy.

We observed breathing pattern abnormalities and arterial oxygen desaturation in patients with stable congestive heart failure during overnight polysomnography. To determine whether congestive heart failure was the reason for these abnormalities, we then studied six additional patients before and after treatment of heart failure. Breathing was more abnormal (153 +/- 87 episodes/night) during decompensation of heart failure and improved with medical therapy (72 +/- 100 episodes/night) (p less than 0.05). Abnormal breathing patterns resolved in three patients, improved in two, and were unchanged in one patient after therapy. Allographic cardiac transplantation in one patient whose sleep study remained unchanged after medical therapy was associated with resolution of breathing pattern abnormalities and severe desaturation during sleep. Therapy-related improvement in nocturnal respiratory events suggests congestive heart failure is a contributing factor for breathing abnormalities and arterial oxygen desaturation during sleep.

Aged↗
PubMed1987

Metastatic malignant melanoma presenting clinically as obstruction of the right ventricular inflow and outflow tracts. Characterization by magnetic resonance imaging.

Metastatic disease involving the heart may present in a variety of fashions. A patient with melanoma metastatic to the right ventricle which was diagnosed clinically by evidence of recent onset of right ventricular inflow and outflow tract obstruction is described. Important information regarding the extent of the metastatic process and potential resectability of the tumor was gained by magnetic resonance imaging.

Cardiomegaly↗