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Biomedical subjects

W Markiewicz

Publications and source records attributed to W Markiewicz.

At least 37 records · Page 2Linked to original sources
PubMed1988

Beneficial effects of verapamil during metabolic acidosis in isolated perfused rat hearts.

Metabolic acidosis was produced in two groups of isolated, glucose-perfused beating rat hearts. The first group (control) was untreated whereas the second group was pretreated for 48 h by the addition of verapamil (1.2 g/L) to the drinking water. Untreated hearts all developed asystole during a 30 min perfusion with an acidotic substrate (pH = 6.8) or during subsequent reequilibration with physiologic substrate (pH = 7.4). Prior to asystole, all untreated hearts showed evidence of severe mechanical and biochemical deterioration evaluated by 31 P NMR spectroscopy. In contrast, hearts of treated rats showed less mechanical and metabolic deterioration, and all recovered during reequilibration. The mechanism of protection of verapamil against the effects of metabolic acidosis is unclear but appears to be related to preserved mitochondrial function by the drug and not to a reduced demand for energy.

Acidosis↗
PubMed1987

Regional left ventricular wall thickening by magnetic resonance imaging: evaluation in normal persons and patients with global and regional dysfunction.

Gated magnetic resonance imaging (MRI) provides excellent anatomic evaluation of the heart, but its capability for assessing cardiac physiology is less clear. Accordingly, regional left ventricular (LV) wall thickening was evaluated by multiphasic transverse images in 37 patients with a variety of myocardial diseases and in 9 normal subjects. Angiography and 2-dimensional echocardiography (2-D echo) were used for comparison. End-diastolic and end-systolic wall thickness, absolute systolic wall thickening and percent systolic wall thickening were determined in 7 regions. Mean systolic wall thickening in normal subjects was not significantly different among the regions. However, there was considerable individual variation in wall thickening, ranging from 18 to 100%. Patients with LV hypertrophy (n = 4), amyloid cardiomyopathy (n = 1), constrictive pericarditis (n = 5), and hypertrophic cardiomyopathy (n = 3) had absolute and percent systolic wall thickening within normal limits. Infarcted segments in patients with ischemic heart disease (n = 17) had reduced absolute and percent systolic wall thickening, often combined with diastolic wall thinning, whereas mean percent systolic wall thickening in adjacent normal myocardial regions was higher than in normal volunteers (p less than 0.001). In patients with coronary artery disease, MRI had a sensitivity and specificity of 93% in detecting regional wall motion abnormalities. Because sagittal images were not acquired, inferior wall motion abnormalities were not assessed by MRI due to parallel wall sectioning in transverse images.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomegaly↗
PubMed1987

Evaluation of the right ventricle by magnetic resonance imaging.

The ability of magnetic resonance imaging to evaluate right ventricular architecture and size was assessed in 149 subjects (26 normal volunteers and 123 patients with heart disease). The right ventricular myocardium was clearly delineated from adjacent structures in all patients. The trabeculated pattern of the right ventricle was well seen and was most evident during systole and in patients with right ventricular hypertrophy. The moderator band was discernible in 72% of the subjects, whereas smaller muscular structures such as the papillary muscles were identified less frequently. Magnetic resonance imaging provided a good image of the tricuspid valve leaflets but did not show the pulmonic leaflets well. The clear visualization of the endocardial and epicardial borders obtained with magnetic resonance imaging allowed measurement of wall thickness and of the internal dimensions of the cavity in normal subjects, in patients with moderate to severe systolic overload, and in patients with moderate to severe diastolic overload. Patients with severe systolic overload of the right ventricle had markedly thicker walls when compared with patients without this condition. The mean internal dimension at end diastole of patients with severe diastolic overload of the right ventricle was significantly increased when compared to other subgroups. Magnetic resonance imaging provides tomographic images of the right ventricle with clear distinction of the endocardial and epicardial surfaces that can be useful for quantitative and qualitative assessment of this complex structure.

Adolescent↗
PubMed1987

Influence of heart rate on metabolic and hemodynamic parameters in the Syrian hamster cardiomyopathy.

The effect of varying heart rate in 155- to 170-day-old isolated, perfused cardiomyopathic Syrian hamster hearts was evaluated by 31P nuclear magnetic resonance spectroscopy. At a low paced heart rate of 170 bpm, cardiomyopathic hearts did not differ from normal hearts except for a lower developed left ventricular pressure. As pacing rate was increased progressively to 270/min, cardiomyopathic hearts showed prolongation of contraction, which led to a pronounced rise in diastolic pressure as the interstimulus interval shortened. This was accompanied by a marked decrease in energy-rich phosphorus compounds. By contrast, increasing heart rate in normal hearts did not change left ventricular pressure and caused only a mild reduction in energy-rich phosphorus compounds. Intracellular pH of cardiomyopathic animals paced at 270 bpm was significantly lower than in normal animals. Thus, indices reflecting mitochondrial function of 155- to 170-day-old cardiomyopathic hamsters appear adequate at low heart rate. Increasing the heart rate unmasks latent mitochondrial dysfunction.

Adenosine Triphosphate↗
PubMed1987

Measurement of ventricular volumes in the dog by nuclear magnetic resonance imaging.

Nuclear magnetic resonance (NMR) imaging is a new, noninvasive approach for imaging the cardiovascular system. Being a three-dimensional technique, NMR imaging has the capability of measuring volumes without the need for assumptions regarding ventricular geometry. In this study, the technique was validated in 19 excised dog hearts, filled with silicone-rubber, imaged using a multislice spin-echo sequence. The volume of the cavity in each slice was calculated from the number of pixels outlined for each slice multiplied by the pixel volume. Ventricular volumes measured by NMR imaging were highly correlated with cast volumes measured by water displacement: right ventricle (RV):RVNMR = 1.05 RVcast - 1.62; r = 0.99, SEE = 0.96 ml; left ventricle (LV):LVNMR = 0.98 LVcast + 0.35, r = 0.98, SEE = 1.48 ml. After validation in casts, NMR imaging volumes were measured in eight living dogs using a multiphasic gated technique to obtain images at 5, 105, 205, 305 and 405 ms after the QRS complex. Cardiac output (CO) and stroke volume (SV) measured by NMR imaging were significantly correlated with thermodilution (TD) measurements (CONMR = 0.63 COTD + 0.51 liters/min; r = 0.78, SEE = 0.57 liters/min; SVNMR = 0.67 SVTD + 1.95 ml; SEE = 5.58 ml). Right and left stroke volumes were closely related (LVSVNMR = 0.9 RVSVNMR + 1.75; r = 0.94, SEE = 4.32 ml), with the slope and intercept of the regression line showing no difference from 1 and 0, respectively. However, volumes determined by NMR imaging underestimated the thermodilution measurements, presumably reflecting the inability to obtain a true systolic image with the present sampling rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Prolyl hydroxylase activity in liver and serum of rats and human subjects intoxicated by chronic administration of ethanol.

It was found that chronic intoxication of rats with ethanol results in an increase in prolyl hydroxylase activity in liver and serum of the investigated animals. Similar effects have been observed in some alcoholic patients. We hope that the assay of prolyl hydroxylase in serum or in liver biopsy samples might be useful for the diagnosis and prognosis of the tendency of some individuals to develop liver cirrhosis.

Alcoholic Intoxication↗
PubMed1986

Cardiac tamponade in medical patients: treatment and prognosis in the echocardiographic era.

Experience was reviewed in the management of pericardial tamponade in 36 patients with emphasis on factors governing short and long-term survival. Malignant pericardial effusion was the most common etiology and accounted for pericardial tamponade in 14 of the 36 patients (39%). Of the 36 patients, three received medical therapy alone, 18 were treated by one or more needle pericardiocentesis, pericardial drains were inserted in six patients, and thoracotomy was performed in nine. Needle pericardiocentesis was attempted as the initial therapy in all but two patients and was initially successful in relieving tamponade in 30 patients. Twenty-four patients died during a follow-up of from 1 day to 6 years. Delay in diagnosing tamponade was frequent and accounted for three deaths. Two more patients died from recurrent tamponade following initial relief. Eighteen patients died primarily from complications related to their basic illness, though recurrent pericardial effusion was a contributory factor in five. One patient died following pericardiectomy. The remaining 12 patients are well and free of pericardial disease. Short-term survival in pericardial tamponade is mostly dependent upon early diagnosis and relief of tamponade. Long-term survival depends upon the prognosis of the primary illness, irrespective of the mode of treatment used.

Adolescent↗
PubMed1986

Evaluation of the hereditary Syrian hamster cardiomyopathy by 31P nuclear magnetic resonance spectroscopy: improvement after acute verapamil therapy.

The relation between metabolic and functional derangement in various cardiomyopathies has not been well characterized. This information was specifically sought in a spontaneous cardiomyopathic model. Metabolic and hemodynamic parameters were obtained in glucose-perfused beating hearts of 180-200-day-old cardiomyopathic Syrian hamsters and age-matched healthy animals. This period in the cardiomyopathic hamster lifetime is intermediary between the necrotic phase and the appearance of heart failure. We used 31P nuclear magnetic resonance spectroscopy to analyze energy metabolites and intracellular pH. Cardiomyopathic hamsters had significantly higher mole fraction values for inorganic phosphate, lower phosphocreatine mole fraction as well as lower phosphocreatine/inorganic phosphate and adenosine triphosphate/inorganic phosphate ratios. Analysis of pH indicated the presence of regions of increased acidity within the heart of myopathic hamsters. Cardiomyopathic hamsters also had significantly lower left ventricular pressure, coronary flow, and myocardial oxygen consumption. Separate groups of normal and myopathic hamsters were given verapamil for 24 hours (one injection of 4 mg/kg s.c. followed by 1.2 g/l in drinking water). Verapamil-treated myopathic hamsters had evidence of markedly improved mitochondrial function when compared with untreated animals. Left ventricular pressure and coronary flow rose to normal levels. Replacing glucose by pyruvate in the perfusate of myopathic hamsters results in a marked increase in left ventricular pressure, coronary flow, and oxygen consumption with a moderate rise in phosphocreatine. Thus, 180-200-day-old cardiomyopathic hamster heart is characterized by evidence of decreased mitochondrial function, by areas of increased acidity within the heart, and by reduced left ventricular function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1986

The effect of alfentanil on experimental myocardial infarction size: a comparison with fentanyl and halothane.

We compared the action of alfentanil on experimental myocardial infarction size with two widely used anesthetic drugs: fentanyl and halothane. Myocardial infarction size, measured by histological techniques, was identical for the three drugs investigated. Our results demonstrate that the action of alfentanil on factors governing myocardial oxygen supply and demand in the rat with coronary artery ligation is no different from the action of fentanyl or halothane.

Alfentanil↗
PubMed1986

Contribution of echocardiography to cardiac diagnosis.

In order to quantify information provided by echocardiography for residents in internal medicine and for cardiologists, 150 selected patients were studied by echocardiography, and the ultrasonic diagnosis was compared with the clinical evaluation. Among 144 patients with adequate visualization of the heart, echocardiography provided findings that were totally unexpected to the residents in 13 (9%) and to the cardiologist in 9 (6%) patients. Echocardiography also provided information relevant to the management of the patient in another one-third of the cases. Both the residents and the cardiologist were able to correctly predict the cause of cardiomegaly and the mechanism of heart failure in most patients presenting with these findings. Despite the introduction of cross-sectional echocardiography, the amount of information contributed by echocardiography has not increased since 1978, when a similar study was performed at our institution. This may reflect increased clinical skill among residents, probably due to long-term exposure to echocardiography during their training.

Adolescent↗
PubMed1985

Echocardiographic evaluation after blunt trauma of the chest.

We studied by cross-sectional echocardiography 27 consecutive subjects with severe blunt trauma of the chest. Inadequate studies were obtained in 6 subjects (22%). Abnormal, unexpected findings were noted in 6 of the remaining 21 subjects (29%): moderate size pericardial effusion in 3 and focal ventricular dysfunction in 4. No patient with echocardiographic abnormality was suspected clinically of having heart damage. One of the 6 subjects with abnormal echocardiographic findings died from sudden asystole 6 days later. The remaining 5 patients had normal echocardiographic findings when studied 1 week after trauma. This study shows that, following blunt chest trauma, cross-sectional echocardiography can detect unsuspected myocardial and pericardial damage in an appreciable number of patients. Ultrasonic examination of the heart complements other investigations in establishing the diagnosis of heart damage and may help improve the care of patients with heart trauma.

Adolescent↗
PubMed1979

The heart in acute glomerulonephritis: an echocardiographic study.

Patients with acute glomerulonephritis often are seen with signs suggesting heart failure. Whether these signs are due to fluid overload secondary to kidney damage only, or whether there is associated myocardial damage has not been elucidated. Fourteen children with acute glomerulonephritis were studied by echocardiography during the edematous phase of the disease and five months later to evaluate cardiac function in this disease. Left ventricular size and function remained normal in all children throughout the study. The most consistent finding was enlargement of the left atrium during the edematous phase with a return toward normal values five months later. There was no correlation between blood pressure and the echocardiographic findings. This study suggests that signs of heart failure in acute glomerulonephritis are not due to myocardial damage but probably reflect fluid overload.

Cardiomegaly↗