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Biomedical subjects

M I Dunn

Publications and source records attributed to M I Dunn.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1985

Hemodynamic and metabolic effects of enalapril in patients with heart failure.

Placebo and enalapril were added on a double-blind basis to conventional treatment in 14 patients with congestive heart failure (CHF), New York Heart Association class II-III. The patients were followed for 14 weeks and their performance was evaluated by a treadmill test, ejection fraction by nuclear scan, cardiothoracic ratio, and Yale Scale score. Metabolic studies were done to test any adverse effects of the drugs. Enalapril decreased arterial pressure and cardiothoracic ratio, and increased ejection fraction. Placebo exerted no significant effects. However, both drugs improved treadmill time and Yale Scale score. No adverse metabolic or clinical effects were observed with either drug. Based on these limited observations we conclude that: Enalapril is a useful ancillary agent to conventional treatment of CHF; it exerts its effects through afterload and preload reduction; and it is safe and well tolerated and has a prolonged duration of action.

Aged↗
PubMed1985

Streptokinase.

Explore the source record for details and available documents.

Cardiac Catheterization↗
PubMed1983

Cardiogenic pulmonary edema.

Cardiogenic pulmonary edema is a medical emergency and must be treated quickly and aggressively with oxygen and intravenous medications. Hemodynamic improvement may precede clinical improvement by several hours.

Heart Diseases↗
PubMed1981

Guanadrel. A new antihypertensive drug.

Guanadrel sulfate, a new adrenergic neuron inhibitor similar to guanethidine sulfate, was tested on 199 outpatients by 11 investigators. The patients had mild, moderate, or severe hypertension as determined by diastolic blood pressures of 95 to 105, 106 to 114, and 115 to 120 mm Hg, respectively. Guanadrel was found to be an effective antihypertensive agent for all levels of hypertension. Since guanadrel has a short onset of action and a short offset of action, which prevents many of the side effects of guanathidine, the dosage could be adjusted rapidly and safely. At low doses side effects are infrequent. There was no organ toxicity and no CNS effect. Guanadrel should be an effective step II or step III drug for treatment of hypertension.

Adult↗
PubMed1979

Progression of aortic stenosis.

We assessed progressive stenosis of the aortic valve in 11 adult patients (mean age of 48 years) with aortic stenosis who had undergone two cardiac catheterizations without intervening aortic valve surgery. The mean time between cardiac catheterization was 59 months (range 20 to 133). No patients had mitral valve disease. Two patients had coronary artery disease. The results showed that progressive stenosis of the aortic valve occurred in 10 of 11 patients with a significant decrease in the calculated mean aortic valve area from 1.2 +/- 0.2 sq cm to 0.7 +/- 0.1 sq cm (P less than 0.005); a significant increase in mean left ventricular peak systolic pressure from 149 +/- 8 mm Hg to 199 +/- 3 mm Hg (P less than 0.01), and a significant increase in mean left ventricular aortic pressure gradient from 31 +/- 4 mm Hg to 75 +/- 13 mm Hg (P less than 0.005). On an individual basis, the change in left ventricular pressure and the left ventricular-aortic gradient did not always reflect the decrease in aortic valve area because of variations in cardiac output. The shortest period of time in which progression of aortic stenosis occurred was 27 to 29 months. Thus, progressive stenosis of the aortic valve occurs in adults with isolated aortic valvular stenosis. Significant decrease in the aortic valve area can develop in as short a period as 27 to 29 months.

Adult↗
PubMed1978

Echocardiographic features of an aneurysm of the left sinus of Valsalva.

The echocardiographic features of an aneurysm of the left sinus of Valsalva are described and correlated with angiographic findings. The echocardiogram showed the presence of a thin line of echoes occurring proximal to the anterior leaflet of the mitral valve and moving in and out of apposition with the posterior aortic wall. During systole, this line of echoes moved away from the aorta into the left atrium, and during diastole, the line moved into the aorta. Recognition of these features provides a potential noninvasive way to diagnose aneurysms of the left sinus of Valsalva prior to rupture.

Adult↗