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Biomedical subjects

M A Quinones

Publications and source records attributed to M A Quinones.

At least 73 records · Page 4Linked to original sources
PubMed1981

Combined vasodilator and inotropic therapy of heart failure: experimental and clinical concepts.

Vasodilators facilitate ventricular emptying by affording earlier onset of left ventricular (LV) ejection and increased stroke volume with achievement of a reduced end-systolic pressure and volume. Agents with positive inotropic properties increase stroke volume by shifting the end-systolic pressure-volume curve to the left through augmented force and velocity of contraction. With impedence reduction, improvement in pump performance occurs concomitant with reduced cardiac energy requirements (MVO2); positive inotropic agents most circumstances increase MVO2. The combination of a vasodilator and positive inotropic agent, as opposed to either alone, in the conscious animal shifts to the left and increases the slope of the LV end-systolic pressure-volume relation. Cardiac efficiency, defined by the slope of the relation between stroke volume and systolic tension, is increased by the combination of the drugs. In clinical heart failure, nitroprusside alone lowers LV preload with a modest increase in cardiac output (CO); dopamine markedly increases CO with little fall in LV preload. In combination the two agents achieve the individual beneficial effects of each drug, and cardiac efficiency indices are improved. Thus combined vasodilator and inotropic therapy appears to have a sound physiologic rationale and clinically documented beneficial effect superior to either modality alone.

Animals↗
PubMed1981

Left ventricular diastolic performance at rest and during exercise in patients with coronary artery disease. Assessment with first-pass radionuclide angiography.

We used first-pass radionuclide angiocardiography to assess filling fraction during the first third of diastole, peak filling rate and peak filling rate during the first third of diastole as indexes of left ventricular diastolic performance at rest and after upright bicycle exercise in 32 normal patients and 68 patients with coronary artery disease. The mean filling fraction was unchanged from rest to exercise in normal patients (47+/- 15% vs 46 +/- 13%; NS). Even in 49 coronary patients with normal (greater than or equal to 50%) ejection fraction at rest, filling fraction was less than that in normal patients at rest (35 +/- 11% vs 47 +/- 15%, p less than 0.001). Despite similar resting heart rates, patients with coronary disease had lower (p less than 0.001) peak filling rate and peak filling rate during the first third of diastole than normal patients. With exercise, filling fraction decreased (p less than 0.001) from the resting value in coronary patients. These data suggest that (1) indexes of diastolic performance can be noninvasively assessed at rest and during exercise using first-pass radionuclide angiocardiography, (2) abnormalities in early diastolic performance are often present at rest in patients with coronary artery disease despite normal systolic performance, and (3) exercise-induced ischemia results in increased early diastolic dysfunction in patients with coronary disease.

Adult↗
PubMed1981

A new, simplified and accurate method for determining ejection fraction with two-dimensional echocardiography.

A new method to determine left ventricular (LV) ejection fraction (EF) with wide-angle, two-dimensional echocardiography (2-D echo) has been developed using the parasternal long-axis, apical four-chamber and apical long-axis views. End-diastolic and end-systolic measurements of LV short axes at the base and mid-LV cavity in the parasternal long-axis view and at the upper, middle and lower thirds of the cavity in the apical views are made, from which an averaged minor axis at end-diastolic and at end-systole is calculated. Fractional shortening of the LV long axis (delta L) is estimated from apical contraction. Satisfactory 2-D echoes were obtained in 55 of 58 nonselected patients (all three views in 32 patients, two views in 22 and one view in one); 42 of 55 patients had coronary artery disease. EF by 2-D echo was compared with EF by gated cardiac blood pool imaging in all patients (r = 0.927, SEE = 6.7%) and to EF by single-plane cineangiography (angio) in 35 of 55 patients (r = 0.913, SEE = 7.4%). LV dyssynergy was frequently present and involved the apex in 29 of 55 patients. Using angio as the standard for evaluating wall motion at the apex, 2-D echo was 100% sensitive and specific in detecting abnormal apical wall motion. We conclude that EF can be determined accurately with 2-D echo in a large group of patients with and without dyssynergy by a simple method that eliminates the need for planimetry or computer assistance.

Adult↗
PubMed1980

Assessment of pulsed Doppler echocardiography in detection and quantification of aortic and mitral regurgitation.

Pulsed Doppler echocardiography was employed to detect disturbed or turbulent flow diagnostic of aortic or mitral regurgitation. Sensitivity, specificity, diagnostic accuracy, and predictive value were assessed by the independent interpretation and comparison of aortic root angiograms (91 patients) and left ventriculograms (94 patients) to the time interval histogram display of the pulsed Doppler. Sensitivity of Doppler in detecting mitral regurgitation was 94 per cent, with specificity 89 per cent, predictive value 81 per cent, and diagnostic accuracy 90 per cent (32 patients with, 62 without regurgitation). In aortic regurgitation, sensitivity was also 94 per cent, specificity 82 per cent, predictive value 94 per cent, and the diagnostic accuracy was 91 per cent (69 patients with, 22 without aortic regurgitation). Additionally, no Doppler evidence of mitral or aortic regurgitation was present in 20 normal subjects. The aetiology of left-sided valvular regurgitation varied widely, with prosthetic valvular insufficiency being the cause of mitral and aortic regurgitation in seven and 10 patients, respectively. Sixteen of 17 (94%) paraprosthetic leaks were correctly identified by pulsed Doppler. In patients with aortic regurgitation the flow-velocity curve recorded in the ascending aorta frequently showed a negative (or reversed) diastolic component, the magnitude of which (expressed as percentage negative area) correlated significantly with angiographic severity of regurgitation. Thus, pulsed Doppler echocardiography is a highly accurate and objective non-invasive technique for detecting mitral and aortic regurgitation. In aortic regurgitation, estimation of severity is possible from inspection of the Doppler ascending aortic flow velocity curve.

Aortic Valve Insufficiency↗
PubMed1980

Exercise-induced ventricular tachycardia. Clinical features, relation to chronic ventricular ectopy, and prognosis.

To determine the clinical status, the occurrence of chronic ambulatory arrhythmias, and the prognosis of patients with exercise-induced ventricular tachycardia, 26 patients with ventricular tachycardia during or immediately following exercise on a treadmill were evaluated. Of the 26 patients, 16 had coronary arterial disease, two had nonischemic cardiomyopathy, and eight had no other cardiac disease. Eleven (61 percent) of the 18 patients with heart disease developed ventricular tachycardia during exercise, in contrast to six (75 percent) of eight normal subjects who had ventricular tachycardia after exercise. In eight patients with repeat stress testing, four (50 percent) had reproducible ventricular tachycardia or malignant ventricular ectopic beats. In 19 (73 percent) of 29 patients, malignant ventricular ectopy occurred on random 24-hour electrocardiographic monitoring; ventricular tachycardia occurred in 5/26 (19 percent), and malignant ventricular ectopic beats occurred in 14/26 (54 percent). Fifteen (83 percent) of 18 patients with cardiac disease vs 4 (50 percent) of eight normal subjects (P less than 0.05) evidenced malignant ventricular ectopy during ambulatory monitoring. Only one episode of sudden cardiac death occurred in 24 patients followed for 21 months. Thus, 30 percent (eight) of the patients with exercise-induced ventricular tachycardia had no evidence of heart disease. Furthermore, exercise-provoked ventricular tachycardia presaged sudden death in only one of 24 patients; however, ventricular tachycardia with exercise correctly predicts the presence of chronic advanced ventricular ectopic beats or ventricular tachycardia in 73 percent (19/26) of the patients.

Adult↗
PubMed1979

A vitamin profile of heroin addiction.

Circulating thiamine, riboflavin, nicotinates, folates, vitamin B12, B6, A, and carotenes of 149 heroin addicts aged 17-60 years were compared to 204 healthy subjects not using drugs or vitamins. Only 24 per cent of the addicts had no evidence of hypovitaminemia; 45 per cent and 37 per cent had vitamin B6 and folate deficit respectively, whereas deficits of thiamine, vitamin B12, riboflavin, and nicotinate were recorded for 13-19 per cent of the addict population; impaired liver function in addicts did not influence these results.

Adolescent↗
PubMed1979

Evaluation of drug abuse rehabilitation efforts: a review.

During the 1960s, three modalities of treatment aimed at rehabilitation of the drug abuser (methadone maintenance, outpatient drug free treatment, and the residential therapeutic community) were developed. Large amounts of public and private monies have gone to supporting these modalities; little evaluation as to the efficacy of such rehabilitation efforts has been done. This paper attempts to delineate the evaluative research efforts undertaken in the drug abuse field to date. In addition, the findings of an eight-year evaluation of six drug treatment programs in Newark, NJ are presented. The authors propose a paradigm for quick, effective evaluation of drug and alcohol programs at minimal cost.

Ambulatory Care↗
PubMed1979

Training minorities for health careers: a five-year follow-up study.

This study investigates the economic status of 69 residents of Newark, New Jersey, who completed health career programs at the College of Medicine and Dentistry of New Jersey in June 1973. The subjects were black females from socially and economically disadvantaged backgrounds ranging in age from 20 to 37 years. Approximately 28% of the 85 subjects who started the program had dropped out of high school by the 11th grade: three had completed the ninth grade and 54 were high school graduates. None had received postsecondary education. Candidates were recruited from the city welfare roster and referred to a selection committee consisting of Newark officials, community residents and representatives from the New Jersey Medical School. Accepted candidates were given first, second and third choices for career selection. Prior to training, 44 subjects were unemployed or receiving public assistance. Only six graduates now receive public assistance.

Black or African American↗
PubMed1978

Percentage of shortening of the echocardiographic left ventricular dimension. Its use in determining ejection fraction and stroke volume.

The percentage of shortening of the echocardiographic left ventricular dimension (% delta D) was prospectively evaluated in 42 patients without detectable asynergy during diagnostic cardiac catheterization and was found to correlate well with angiographic ejection fraction (r = 0.90). Ejection fraction was calculated as the product of % delta D X 1.7 or as % delta (D2), both formulae having similar degrees of accuracy and a better correlation with the angiographic determination than conventional formulae. Ejection fractions (angiographic and echocardiographic) of 51 percent or greater were always associated with a % delta D of 30 percent or more. In five patients the echocardiographically derived ejection fractions were normal (greater than or equal to 51 percent), while the angiographic ejection fractions were reduced; four of these patients had valvular regurgitation. End-diastolic volumes were calculated from end-diastolic echocardiographic dimensions utilizing a linear regression equation derived from correlating the end-diastolic echocardiographic dimension with the end-diastolic volume in 27 patients without valvular regurgitation (end-diastolic echocardiographic dimension ranged from 3.7 to 8.2 cm). The value for stroke volume determined as the product of calculated end-diastolic volume times ejection fraction correlated with the angiographically determined stroke volume (r = 0.88; standard error of estimate, +/- 11 ml) better than the value for stroke volume derived from conventional echocardiographic formulae.

Adolescent↗
PubMed1977

Restructuring rehabilitation for women: programs for the female drug addict.

Two residential therapeutic communities for female addicts--one coeducational and the other all female--encountered serious problems shortly after their formation. The authors found that the male and female staff of the coeducational program had quite different perceptions of the purposes and characteristics of the women's part of the program. In both programs the female staff held such strongly ambivalent feeling toward their roles as women and authority figures that they had difficulty functioning effectively. The authors suggest the need for research that will identify the female addict's special needs, and a restructuring of programs to meet those needs. Further, training programs for female staff must enable them to distinguish between their own ideals and their clients' needs.

Attitude of Health Personnel↗