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Biomedical subjects

M J Ptacin

Publications and source records attributed to M J Ptacin.

16 recordsLinked to original sources
PubMed1990

Cardiovascular regulation during head-out water immersion exercise.

Head-out water immersion is known to increase cardiac filling pressure and volume in humans at rest. The purpose of the present study was to assess whether these alterations persist during dynamic exercise. Ten men performed upright cycling exercise on land and in water to the suprasternal notch at work loads corresponding to 40, 60, 80, and 100% maximal O2 consumption (VO2max). A Swan-Ganz catheter was used to measure right atrial pressure (PAP), pulmonary arterial pressure (PAP), and cardiac index (CI). Left ventricular end-diastolic (LVED) and end-systolic (LVES) volume indexes were assessed with echocardiography. VO2max did not differ between land and water. RAP, PAP, CI, stroke index, and LVED and LVES volume indexes were significantly greater (P less than 0.05) during exercise in water than on land. Stroke index did not change significantly from rest to exercise in water but increased (P less than 0.05) on land. Arterial systolic blood pressure did not differ between land and water at rest or during exercise. Heart rates were significantly lower (P less than 0.05) in water only during the two highest work intensities. The results indicate that indexes of cardiac preload are greater during exercise in water than on land.

Adult↗
PubMed1990

Cardiovascular ochronosis: a case report and review of the medical literature.

Ochronosis is a rare disorder of tyrosine metabolism due to a deficiency of the enzyme homogentisic acid oxidase. The most common clinical manifestations include alkaptonuria, spondyloarthropathy, large joint arthritides and pigmentation of cartilage. Cardiac involvement may occur due to the deposition of polymerized homogentisic acid in the aortic, mitral and pulmonic valves. Usually, this leads to increasing rigidity and calcification. The only functionally significant valve lesion reported appears to be aortic stenosis. A possible link between ochronosis and coronary artery disease has been postulated. Further, a link between peripheral vascular disease and ochronosis may be present. We describe a case of ochronotic cardiovascular disease and review the literature on the subject.

Aged↗
PubMed1988

Spontaneous recovery of left ventricular function following acute anterior myocardial infarction.

Four patients with acute anterior wall myocardial infarction showing spontaneous and marked improvement in systolic left ventricular function are described. All 4 patients showed abnormal Q waves and severe wall motion abnormalities soon after acute infarction. In all 4 patients, at least some regeneration of R-wave forces occurred and the regional wall motion in the involved area of the left ventricle improved dramatically without coronary angioplasty or surgical revascularization during the intervening period. The improvement in left ventricular function was attributed to spontaneous increase in nutrient flow to the involved area. It is concluded that Q waves and severe wall motion abnormalities do not necessarily indicate irreversible scar formation.

Electrocardiography↗
PubMed1988

Comparison of ST segment depression in upright treadmill and supine bicycle exercise testing.

Significant differences in the hemodynamic response to upright and supine exercise have been reported in patients with coronary artery disease. The purpose of the present study was to compare the degree of myocardial ischemia as assessed by ST segment depression during upright treadmill and supine bicycle exercise in 98 patients with coronary artery disease and in 34 patients with normal coronary arteries. The amount of ST segment depression at maximal exercise in patients with coronary artery disease was 0.90 +/- 0.80 mm for treadmill and 1.34 +/- 1.09 mm for supine bicycle (p less than 0.001). The amount of ST segment depression during treadmill and supine bicycle exercise tests was also compared at highest similar heart rates (0.68 +/- 0.77 versus 1.17 +/- 1.01, p less than 0.001), at highest similar rate-pressure products (0.71 +/- 0.77 versus 1.08 +/- 1.04, p less than 0.001), at highest similar metabolic equivalents of oxygen consumption (MET) levels (0.69 +/- 0.75 versus 1.20 +/- 1.05 mm, p less than 0.001) and at the onset of angina (0.84 +/- 0.73 versus 1.18 +/- 0.88 mm, p less than 0.001). The rate-pressure product achieved at maximal exercise was similar in both tests (18.74 +/- 5.80 x 10(3) versus 18.81 +/- 5.17 x 10(3), p = NS). The occurrence of angina during treadmill and supine bicycle exercise tests was similar (47 of 98 versus 48 of 98, respectively, p = NS). For the detection of coronary artery disease, the sensitivity was 50.0% for treadmill and 63.3% for supine bicycle (p less than 0.05) and the specificity was 73.5 versus 70.6%, respectively (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

The effect of age on hemodynamic response to graded postural stress in normal men.

We studied the hemodynamic effect of graded gravity (g) increments from 10 degrees headdown (-0.17 g) to 70 degrees headup (+0.94 g) tilt on young (20 to 29 years), middle-aged (40 to 49 years) and older (60 to 69 years), healthy men. Thoracic blood volume and ventricular stroke volume decreased linearly with increasing g levels. Heart rates and diastolic pressures increased, but only at the higher g levels; however, the increases were significantly less in the 60- to 69-year-old men. The results indicate that thoracic blood volume and ventricular stroke volume are remarkably gravity dependent over the entire tilt range in all groups, the lesser heart rate and diastolic pressure responses in older participants are significant circulatory handicaps and may contribute to the increased incidence of postural hypotension in elderly persons, the sharp rise in vascular resistance at lower +g levels (when arterial pressure is unchanged) suggests that cardiopulmonary reflexes play an important role in human circulatory adjustment to the headup posture.

Adult↗
PubMed1987

Determination of stroke volume and cardiac output during exercise: comparison of two-dimensional and Doppler echocardiography, Fick oximetry, and thermodilution.

Simultaneous estimates of cardiac output were made during graded upright maximal exercise in 10 male subjects by means of Doppler velocity spectrum of ascending aortic flow, apical two-dimensional echocardiograms, thermodilution, and Fick oximetry. In 15 subjects, aortic annular and root diameters were measured during similar exercise from parasternal two-dimensional echocardiograms. The linear correlation between Doppler, two-dimensional echocardiography, and the invasive estimates ranged from r = .78 to r = .92. Both echocardiographic techniques were able to predict changes in invasive flow estimates with reasonable accuracy. Two-dimensional echocardiographic flow estimates underestimated invasive values by about 60%. The accuracy of Doppler flow estimates varied with the method of estimating aortic cross-sectional area. Greatest accuracy was obtained with areas calculated from diameters measured at the aortic value anulus with the leading edge-to-leading edge method of measurement. Correlation coefficients comparing Doppler and thermodilution flow estimates were generally higher (r = .75 to .96, mean .86) for individuals than for the group, but accuracy of the Doppler estimates in single subjects was quite variable. Aortic diameters did not increase from rest to moderate levels of upright exercise. A 3% to 5% increase in resting aortic diameter was noted in the upright posture as compared with the supine. Doppler flow estimates were obtained in all subjects to maximal exertion but in only a minority of subjects with two-dimensional echocardiography or thermodilution. Thus two-dimensional and Doppler echocardiography offer a noninvasive means of estimating cardiac output during vigorous exercise. The Doppler technique is technically more suitable to the study of exercise than two-dimensional echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Value of exercise electrocardiography to predict additional jeopardized myocardial regions remote from site of previous myocardial infarction.

In order to evaluate the efficacy of exercise electrocardiography (ECG) to identify jeopardized myocardial regions remote from the site of previous infarction, exercise ECG, left ventriculography, and coronary arteriography were performed in 90 patients with previous transmural myocardial infarction (MI). Of the 90 patients, angiographic studies revealed jeopardized myocardial regions in 47 patients. Exercise ECG correctly identified 32 of these 47 patients for a sensitivity value of 68%. There were 43 patients without any additional jeopardized myocardial regions. Exercise ECG correctly identified only 24 of these 43 patients for a specificity value of 56%. The sensitivity and specificity values were similar in patients with prior anterior and inferior wall MI. It is concluded that relatively low sensitivity and specificity values preclude the ability of exercise ECG to accurately identify patients with jeopardized myocardial regions distant from the site of previous MI. Moreover, when such patients were correctly detected, exercise ECG was rather poor in localizing these additional jeopardized myocardial areas.

Angina Pectoris↗
PubMed1983

Spontaneous mediastinal hemorrhage. A complication of intracoronary streptokinase infusion for coronary thrombosis.

A 72-year-old man with a recent inferior-wall myocardial infarction complicated by continued ischemic cardiac pain underwent an intracoronary streptokinase infusion in an attempt to re-establish coronary perfusion. Although the cardiac catheterization and streptokinase infusion were technically uncomplicated, signs of an enlarging mediastinal mass associated with a drop in the hematocrit reading developed in the patient 12 hours after the procedure. Aortography showed no evidence of aortic dissection or laceration. The patient was believed to have a spontaneous mediastinal hemorrhage related to streptokinase infusion.

Aged↗
PubMed1983

Noninvasive evaluation of a left ventricular pseudoaneurysm: complementary role of echocardiographic and nuclear techniques.

This 45-year-old white male was evaluated for congestive heart failure initially ascribed to a rapidly progressive cardiomyopathy. Both radionuclide ventriculography and echocardiography correctly identified a left ventricular pseudoaneurysm as the cause for heart failure. Thallium-201 scintigraphy, by demonstrating a large perfusion defect, suggested a large ostium of the pseudoaneurysm. Following resection of the false aneurysm, a Dacron prosthesis was required to close a large posterior wall defect. We conclude that both radionuclide ventriculography and echocardiography can independently demonstrate a left ventricular pseudoaneurysm. The combined noninvasive approach is able to delineate various anatomical aspects of the pseudoaneurysm and help in planning adequate surgical intervention.

Cardiac Catheterization↗
PubMed1983

Prevalence of mitral prolapse by two dimensional echocardiography in healthy young women.

In order to establish the relative prevalence of mitral valve prolapse as diagnosed by two dimensional echocardiography, we studied 100 presumably healthy young women with two dimensional echocardiography and M-mode echocardiography, history, physical examination, electrocardiography, and phonocardiography. Two dimensional echocardiograms were obtained from parasternal, apical, and subcostal acoustic windows. Mitral valve prolapse was defined as extension of leaflet tissue cephalad to the plane of the mitral annulus into the left atrium; note was also made of any valvular thickening, redundancy, or excessive annular motion. One subject had a midsystolic click and late systolic murmur with evidence of mitral prolapse on both M-mode and two dimensional echocardiography. One subject had a midsystolic click with mitral prolapse demonstrated by two dimensional but not on M-mode echocardiography. One subject had a thick mitral valve on echocardiography but no click or murmur. Four subjects had midsystolic clicks without echocardiographic abnormalities. Mild artefactual pansystolic posterior bowing of the mitral valve on the M-mode echocardiogram could be produced in 20 subjects by incorrect transducer position. We conclude that the prevalence of mitral valve prolapse by two dimensional echocardiography is relatively low in presumably healthy young women. Use of two dimensional echocardiography may avoid overdiagnosis of mitral prolapse and identify a smaller group of individuals with true anatomical abnormalities of the mitral valve.

Adolescent↗
PubMed1982

Evaluation of postresuscitation left ventricular global and segmental function by radionuclide ventriculography in sudden coronary death survivors of prehospital cardiac arrest: Correlation to subsequent short-term prognosis.

Previous data have shown that patients with significant left ventricular (LV) dysfunction, marked abnormalities in resting hemodynamics, and multiple vessel coronary artery disease (CAD) are at increased risk for sudden cardiac death. However, in-hospital assessment of ventricular function in the early postresuscitation period of out-of-hospital cardiac arrest has not been evaluated and related to short-term outcome. By using bedside radionuclide ventriculography (RNV) we evaluated LV ejection fraction (LVEF) and wall motion in 36 nonconsecutive patients within 24 hours of their episode of out-of-hospital cardiac arrest. There were 24 men and 12 women with mean age of 62.3 years (range 21 to 85 years). Total mortality of the entire group was 38.8% at 4 weeks. Eighteen patients had LVEF less than 0.30 and 18 had LVEF greater than 0.30. Mortality in the low LVEF group was 55.5% at 4 weeks versus 22.2% in patients with LVEF greater than 0.30 (p less than 0.05). Patients with normal LV wall motion had no short-term mortality (none of seven), while patients having abnormal LV wall motion had a significantly higher short-term mortality (14 of 29) (p less than 0.05). We conclude that out-of-hospital cardiac arrest survivors have a high incidence of severe LV dysfunction in the early postresuscitation period and that a significantly higher early mortality is seen in the group with LVEF less than 0.30. In addition, abnormalities of LV wall motion by RNV examination demonstrated poorer prognosis in the first 4 weeks than patients with normal LV wall motion.

Adult↗