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Biomedical subjects

J Grimm

Publications and source records attributed to J Grimm.

At least 91 records · Page 5Linked to original sources
PubMed1989

Abnormal coronary vasomotion during exercise in patients with normal coronary arteries and reduced coronary flow reserve.

A reduced coronary flow reserve has been reported in patients with ischemialike symptoms and normal coronary arteries. In 13 such patients, both coronary vasomotion and flow reserve were studied. The luminal area of the proximal and distal third of the left anterior descending and left circumflex artery were determined by biplane quantitative coronary arteriography using a computer-assisted system. Patients were studied at rest, during submaximal supine bicycle exercise (4.0 minutes, 116 W), and 5 minutes after sublingual administration of 1.6 mg nitroglycerin. Heart rate, mean pulmonary pressure, and mean aortic pressure as well as the percent change of both proximal and distal luminal area were determined. In 10 of the 13 patients, coronary sinus blood flow was measured by coronary sinus thermodilution technique at rest and after dipyridamole infusion (0.5 mg/kg in 15 minutes) 10 +/- 5 days after quantitative coronary arteriography. Coronary flow ratio (dipyridamole/rest) and coronary resistance ratio (rest/dipyridamole) were determined in these patients. Patients were divided into two groups according to the behavior of the coronary vessels during exercise (vasodilation, group 1; vasoconstriction, group 2). Coronary vasodilation of the proximal (luminal area +26%, p less than 0.001) and distal (+45%, p less than 0.001) artery was observed in seven patients (group 1) during exercise and after sublingual nitroglycerin (+46%, p less than 0.001; and +99%, p less than 0.001, respectively). In group 2 (n = 6), however, there was coronary vasoconstriction of the distal vessel segments (-24%, p less than 0.001) during exercise, whereas the proximal coronary artery showed vasodilation (+26%, p less than 0.001) during exercise. After sublingual nitroglycerin, both vessel segments elicited vasodilation (distal coronary, +44%, p less than 0.001; proximal coronary artery, +47%, p less than 0.001). Coronary flow ratio amounted to 2.5 in group 1 and 1.2 in group 2 (p less than 0.05) and coronary resistance ratio to 2.7 in group 1 and to 1.2 in group 2 (p less than 0.05), respectively. Thus, among patients with ischemialike symptoms and normal coronary arteries, there is a group of patients (group 2) with an abnormal dilator response of the distal coronary arteries to the physiologic dilator stimulus of exercise and a reduced dilator capacity of the resistance vessels after dipyridamole (abnormal coronary vasodilator syndrome). The nature of this exercise-induced distal coronary vasoconstriction is not clear but might be due to an abnormal neurohumoral tone that may cause or contribute to the blunted vascular response during exercise.

Angiography↗
PubMed1989

Quantification of mitral regurgitation with amplitude-weighted mean velocity from continuous wave Doppler spectra.

Amplitude-weighted mean velocity from continuous wave (CW) Doppler spectra was used to measure aortic flow (QAo) and left ventricular mitral inflow (QLVin). These flows were used to quantify mitral regurgitation fraction: RFm = (QLVin-QAo).QLVin-1.100(%).QLVin was calculated from the diastolic time integral of amplitude-weighted mean velocity that was derived from CW spectra with the transducer placed in the apical window and the CW beam directed toward the left ventricular inflow tract. QAo was obtained from the systolic time integral of amplitude-weighted mean velocity by using the same apical window and directing the CW beam toward the left ventricular outflow tract. In 20 normal subjects, RFm ranged between -6.2% and +8% (mean, -0.8%). In 25 patients with pure mitral regurgitation, RFm obtained by Doppler (y) was compared with RFm calculated from biplane left ventriculography and the Fick method (x). The correlation was r = 0.96, SEE = 6.1% of the mean or 12% of the angio-Fick mean; the regression line was y = 0.96x + 0.18; mean y = 49%, mean x = 51%. It is concluded that RFm can be determined accurately by using amplitude-weight mean velocities from CW Doppler spectra. The advantages of this method are its independence from the measurement of the left ventricular inflow or outflow tract area.

Adult↗
PubMed1989

[Acute hip pain in the adult--assessment by magnetic resonance tomography].

Using the modern cross-sectional imaging technique of MRI, significant improvement has been achieved in the early diagnosis of acute hip diseases, such as avascular femoral head necrosis, transient osteoporosis, coxitis, and tumors, the demarcation of which can be seen by MRI. Studies with MRI in patients with transient osteoporosis have revealed three stages during the clinical course. The focal stage is similar to femoral head necrosis, but always without the typical sclerotic rim. To obtain complete remission, transient osteoporosis only requires immobilization. There are difficulties in diagnosing infected and neoplastic processes.

Acute Disease↗
PubMed1988

Laminar flow induces cell polarity and leads to rearrangement of proteoglycan metabolism in endothelial cells.

Bovine aortic endothelial cells in tissue culture were incubated with [35S]-sulfate to examine the pattern of proteoglycan production at various shear rates. It was observed that culturing bovine aortic endothelial cells under laminar flow changes the secretion pattern of proteoglycans to that observed in perfused organ cultures, induces polarity of secretion, down-regulates proteoglycan biosynthesis and decreases uptake of sulfate. These results indicate that surface shear is a major force influencing the endothelial cellular phenotype. The changed pattern of proteoglycan release under static conditions may contribute to the anticoagulant effect of endothelial cells which is much needed when activated coagulation factors are not dispersed by flow.

Animals↗
PubMed1988

[Assessment of prognosis with Markov chains in chronic cardiovascular diseases in relation to various therapies].

On the basis of 5-years intervention results concerning chronic heart and vessel diseases of a check, which is representative for approx. 280.000 inhabitants of defined territories (EBMO-Cor Berlin), the prognose for the time of 5 and 10 years were estimated. It refers to ambulantories with the diagnosis hypertension and coronary heart disease, who were treated in a different way. The fundamental idea was to extract a prognostic index to make possible a choice of the treatment, adequate to the specific disease and its severe degrees, free of chance. The basic requirement of the application of the "Markoff-model" was the evidence of homogeneity concerning transition of severe degrees, used as reference, which was proved by means of the 2-k-chi 2-Felder-test. By using a starting vector of 1000 patients in each case inquiries about the distribution to the severe degrees had been made. The so achieved results illustrate a therapy-dependent susceptibility of these (morphologically defined) population suffering from a heart disease and allow a forecast, estimated also for a longer period, about the extent of the transition of a respecting and with the possibilities of the outpatient practice defined severe degrees of a heart and circulation disease and with that about chance and risk of a patient. By means of the epidemiological reference of the study the result gains special importance for outpatient practice.

Cardiovascular Diseases↗
PubMed1988

[Coronary vasomotor activity; its significance for the therapy of angina pectoris].

Using quantitative biplane coronary arteriography, coronary vasomotion of normal and stenotic coronary artery segments was studied at rest and during supine bicycle exercise in 37 patients with coronary artery disease. Normal coronary arteries showed vasodilation during exercise, whereas stenotic arteries exhibited vasoconstriction. The occurrence of coronary stenosis narrowing during exercise can be explained either by a collapse of the free vessel wall due to an increase in coronary blood flow velocity (Venturi mechanism) or by insufficient production of the endothelium-derived vasorelaxing factor (endogenous nitrate). To explore further the nature of exercise-induced vasoconstriction of stenotic coronary arteries, intracoronary nitroglycerin, diltiazem or propranolol was given to a subgroup of patients prior to the exercise test. Administration of intracoronary nitroglycerin or diltiazem prevented exercise-induced vasoconstriction, probably due to the direct vasorelaxing effect of the drug on the smooth vasculature. Intracoronary administration of propranolol also prevented exercise-induced vasoconstriction, either due to a reduction in trans-stenotic pressure gradient (local beta blockade with a decrease in local coronary blood flow or an increase in distal arteriolar tone due to unopposed alpha-constrictor tone) or because of a local anesthetic effect of propranolol with a decrease in calcium influx into the smooth vasculature.

Angina Pectoris↗
PubMed1988

Prevention of coronary vasoconstriction by diltiazem during dynamic exercise in patients with coronary artery disease.

Whether exercise-induced vasoconstriction of coronary artery stenoses is modified by the administration of calcium antagonists was examined in 14 patients with classic angina pectoris. In this group the effect of intracoronary diltiazem (2 to 3 mg) on luminal area was evaluated in normal and stenotic segments of epicardial coronary arteries during symptom-limited supine exercise. The luminal area of a normal and a stenotic coronary artery segment was determined by quantitative coronary arteriography with a computer-assisted system. Patients were studied at rest, 6 min after 2 to 3 mg of intracoronary diltiazem, during supine bicycle exercise (96 W) and 5 min after sublingual administration of 1.6 mg nitroglycerin. Heart rate, mean pulmonary and aortic pressure as well as the percent change of both normal and stenotic luminal area were determined. Intracoronary administration of diltiazem was associated with mild dilation of both normal (19%, p less than 0.01) and stenotic coronary luminal area (11%, p less than 0.05). During subsequent exercise, luminal area of the stenotic vessel segment increased by 23% (p less than 0.001) and that of the normal vessel segment by 24% (p less than 0.001), whereas in a previously reported control group, luminal area of the stenotic vessel segment decreased by 29% during exercise. After sublingual administration of nitroglycerin, the luminal area of both the normal and the stenotic vessel segment increased further by 19% (p less than 0.01) and 22% (p less than 0.01), respectively, compared with the values after intracoronary administration of diltiazem.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1988

Correction for preload in assessment of myocardial contractility in aortic and mitral valve disease. Application of the concept of systolic myocardial stiffness.

With single-beat analysis, the new concept of systolic myocardial stiffness is applied to provide a new approach for the assessment of myocardial contractility in aortic and mitral valve disease. Seventy patients underwent diagnostic right and left heart catheterization. Twenty-six patients had aortic stenosis, 18 had aortic insufficiency, and 26 had mitral regurgitation. Patients with aortic stenosis were divided into two groups on the basis of left ventricular mass index less than 172 g/m2 (AS1) and mass index greater than or equal to 172 g/m2 (AS2). The mitral regurgitation patients were divided into those in normal sinus rhythm (MR1) and those in atrial fibrillation (MR2). Nine patients without significant coronary or cardiovascular disease served as controls. Thirteen patients with aortic stenosis and eight with aortic insufficiency were evaluated (average, approximately 18 months) after successful aortic valve replacement. With simultaneous left ventricular pressure and cineangiographic methods, myocardial contractility was assessed by the conventional ejection fraction-afterload relation (uncorrected for preload) and by two new methods that permit the correction of the ejection fraction for preload. Assessments of the contractile state by these two new methods differed from those by the conventional method in 20-40% of the cases studied. Contractile state improved postoperatively in aortic stenosis and aortic insufficiency even in patients with preoperative depressed contractile states. In patients with mitral regurgitation, there was considerable heterogeneity of contractile function preoperatively. Severe left ventricular hypertrophy in aortic stenosis was not a marker for postoperative outcome since contractility was normal postoperatively in AS1 and AS2 in equal numbers. This study demonstrates that preload correction is important in a preoperative assessment of contractility in aortic and mitral valve disease but that it is less important postoperatively, presumably because of reductions in the preload.

Adult↗
PubMed1988

Determination of left ventricular wall thickness and muscle mass by intravenous digital subtraction angiocardiography: validation of the method.

Left ventricular (LV) wall thickness and muscle mass are important measures of LV hypertrophy. In 24 patients LV end-diastolic wall thickness and muscle mass were determined (two observers) by digital subtraction angiocardiography (DSA) and conventional LV angiocardiography (LVA). Wall thickness was determined over the anterolateral wall of the left ventricle according to the technique of Rackley (method 1) or by planimetry (method 2). Seventeen patients were studied at rest and seven during dynamic exercise. Wall thickness correlated well between LVA and DSA; the best correlations were obtained by a combined subtraction mode using either method 1 or 2 (method 1, r greater than or equal to 0.80; method 2, r greater than or equal to 0.75). The standard error of estimate of the mean (SEE) was slightly lower for method 2 (less than or equal to 10%) than for method 1 (less than or equal to 13%). DSA significantly overestimated wall thickness by 5-7% with method 1 and underestimated by 12-14% with method 2. Muscle mass correlated well between LVA and DSA; the SEE was less than or equal to 15% for method 1 and less than or equal to 12% for method 2. Overestimation of muscle mass by DSA was 7-11% with method 1 and underestimation was 13-15% with method 2. It is concluded that LV wall thickness can be determined accurately by DSA with an SEE ranging between 10 and 13%. Determination of LV muscle mass is slightly less accurate and the SEE is slightly larger ranging between 13 to 17%. With method 1, wall thickness and muscle mass were overestimated and with method 2 underestimated.

Adult↗
PubMed1987

[Problem-specific grading in disease course assessment and calculation of the likelihood of transition of chronic cardiovascular diseases].

For the course rating of cardiovascular caused drop in efficiency a problem-specific grading is introduced, the characterization of which is composed of simple, non-invasive parameters. The grading is specified for 4 clinical diagnostic classes (hypertension, coronary heart diseases, pulmonary heart, "other heart and vessel diseases") and takes into consideration the frequent coincidence or connection of several diagnoses of heart and vessel diseases with each other. The choice of parameter and connection have to fulfil the demand, which is essential for the course rating of heart and vessel diseases, like practicability proportionate with the frequency of heart and vessel diseases, adequate registration of changes in severe degrees, statement about the patient and not about several parameters. Furthermore it has to make it possible to calculate provisional probabilities under variable conditions as well as to make possible a valuation of prognosis. For that purpose the construction of suitable matrixes is shown and an integral projection is represented, which is used for the interpretation of courses dependent on severe degrees. The conception of grading has the function to modify necessary parameters for inclusion in the hierarchy according to medical starting position (for instance primary mode of registration). The model which is applicable to level of population makes possible an electronic data - processing - based evaluation including algorithmic classification.

Cardiovascular Diseases↗
PubMed1987

Is there coronary vasoconstriction after intracoronary beta-adrenergic blockade in patients with coronary artery disease.

Vasomotility of normal and stenosed coronary arteries was studied at rest and during supine bicycle exercise in 10 patients with classical exercise-induced angina pectoris receiving 1 mg intracoronary propranolol before the exercise test (propranolol group). Normal and stenotic coronary lumen areas were determined from biplane coronary arteriograms using a computer-assisted system. Measurements were performed at rest, after 1 mg intracoronary propranolol, during supine exercise (89 W for 3.4 minutes) and 5 minutes after 1.6 mg sublingual nitroglycerin administered at the end of the exercise test. The results were compared with previously obtained data on the effect of dynamic exercise on coronary lumen area in 12 patients receiving no medication (control group) and in 6 patients receiving 0.1 mg intracoronary nitroglycerin before the exercise test (nitroglycerin group). In the control group, coronary stenosis area decreased during exercise to 71% of levels at rest (p less than 0.001) whereas normal coronary lumen area increased to 123% of control (p less than 0.01). In the propranolol group both normal (113%, p less than 0.05 versus rest) and stenotic coronary lumen area (122%, p less than 0.05 versus rest) increased during exercise. A similar increase in both normal and stenotic areas was observed during exercise after pretreatment with 0.1 mg intracoronary nitroglycerin (123%, p less than 0.01 and 114%, p = NS versus rest). Sublingual administration of 1.6 mg nitroglycerin at the end of exercise increased coronary stenosis area to 145% (p less than 0.01 versus rest) in the propranolol group and to 115% in the control group (p = NS versus rest). It is concluded that intracoronary administration of propranolol does not potentiate coronary vasoconstriction of the epicardial vessels at rest and during exercise. In contrast, intracoronary propranolol prevents exercise-induced stenosis narrowing either because of reduced myocardial oxygen demand with a lower coronary blood flow resulting in a smaller transstenotic pressure gradient and, thus, a smaller flow-induced fall in stenosis distending pressure; or because of "local" beta-receptor blockade with unopposed distal arteriolar alpha-receptor tone, resulting in a higher poststenotic pressure and, thus, in a greater stenosis distending pressure; or because of a local anesthetic effect of propranolol with a decrease in calcium influx to the coronary smooth musculature.

Adult↗
PubMed1986

Effect of coronary occlusion during percutaneous transluminal angioplasty in humans on left ventricular chamber stiffness and regional diastolic pressure-radius relations.

The effect of repeated (3 to 10 second) and transient (15 to 75 second) abrupt coronary occlusion on the global and regional chamber stiffness was studied in nine patients undergoing angioplasty of a single proximal left anterior descending coronary artery stenosis. The left ventricular high fidelity pressure and volume relation was obtained before and after the procedure as well as during coronary occlusion, after 20 seconds (n = 9) and after 50 seconds (n = 5). During ischemia, there was an upward shift of the pressure-volume relation. The nonlinear simple elastic constant of chamber stiffness increased from 0.0273 +/- 0.017 before angioplasty (mean +/- SD) to 0.0621 +/- 0.026 after 20 seconds of occlusion (p less than 0.05) and 0.0605 +/- 0.015 after 50 seconds of occlusion (p less than 0.01). In five patients, the postangioplasty value remained higher than the control value, but at the group level the mean value (0.0529 +/- 0.037) was not statistically different. The regional stiffness was determined from the changes in the length of six segmental radii during diastole, from the lowest diastolic to the end-diastolic pressure. The regional constant of elastic stiffness was unaffected in the nonischemic zone. In the adjacent and ischemic zones, the regional stiffness was increased during occlusion (p less than 0.05). These regional abnormalities in diastolic function persisted at the time of postangioplasty measurements, 12 minutes after the end of the procedure. This suggests that recovery of normal diastolic function after repeated ischemic injuries is delayed after restoration of normal blood flow and systolic function.

Angioplasty, Balloon↗
PubMed1986

Vasoconstriction of stenotic coronary arteries during dynamic exercise in patients with classic angina pectoris: reversibility by nitroglycerin.

To study the vasomotility of normal and diseased coronary arteries during dynamic exercise, symptom-limited supine bicycle exercise during cardiac catheterization was performed by 18 patients with classic angina pectoris. The cardiovascular response was assessed by hemodynamic measurements and computer-assisted determination of normal and stenotic coronary artery luminal areas from biplane coronary angiograms made before, during, and after exercise. After baseline measurements were recorded, 12 patients (group 1) performed bicycle exercise for 3.4 min (mean), reaching a maximum workload of 81 W (mean); at the end of exercise they received 1.6 mg sublingual nitroglycerin. After measurements at rest in six other patients (group 2), 0.1 mg intracoronary nitroglycerin was given, followed by exercise (3.8 min, 96 W; NS) and sublingual nitroglycerin as in group 1. During exercise in group 1, luminal area of the coronary stenosis decreased to 71% of resting levels (p less than .001), while area of the normal coronary artery increased to 123% of control (p less than .001). After sublingual nitroglycerin at the end of exercise, area of the normal vessel further increased to 140% of control (p less than .001), while luminal area of the stenosis dilated to 112% of resting levels (p less than .001 vs exercise, NS vs rest). Pretreatment with intracoronary nitroglycerin increased both normal (121%; p less than .05) and stenotic (122%; p less than .05) luminal areas, while preventing the previously observed narrowing of stenosis during exercise (114%; NS). Exercise resulted in a similar heart rate-systolic pressure product and caused angina pectoris in two-thirds of the patients in each group. However, patients pretreated with intracoronary nitroglycerin (group 2) had a lower mean pulmonary arterial pressure during maximum exercise (35 mm Hg) than those patients (group 1) not receiving pretreatment (47 mm Hg; p less than .001). Group 2 patients reached a percentage of their predicted work capacity (65%) that was about the same as that during previous upright bicycle exercise (71%; NS), while group 1 patients had a significantly lower work capacity (51% of predicted) than that before catheterization (82%; p less than .001). Hence, narrowing of coronary artery stenosis during dynamic exercise is attributable to active vasoconstriction due to its reversibility by preexercise intracoronary nitroglycerin. Patients who did not experience narrowing of stenosis during exercise (group 2) had less evidence of myocardial ischemia (lower mean pulmonary arterial pressure) and maintained their work capacity.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1986

Diastolic filling dynamics in patients with aortic stenosis.

Left ventricular filling dynamics were investigated in 24 patients with aortic stenosis (AS). Biplane cineangiography was performed with simultaneous micromanometry in these 24 patients and in six control subjects. Twelve of the patients with AS had moderate hypertrophy with a left ventricular muscle mass index of less than 180 g/m2 (ASI group) and 12 had severe hypertrophy with an index of 180 g/m2 or more (AS2 group). Filling dynamics were also evaluated postoperatively in eight patients in the AS1 and six patients in the AS2 group. Preoperatively, end-diastolic and end-systolic volume indexes were larger and ejection fraction was lower in the AS2 compared with the control or AS1 group. Percent volume increase during the first half of diastole (%V1) was smaller in the AS1 than in the AS2 group. Peak filling rate in the first half of diastole (PFR 1) was higher in the AS2 than in the control or in AS1 group, while peak filling rate in the second half of diastole (PFR2) was considerably greater in the AS1 group than in the other two groups. The time constant of left ventricular pressure decline, an index of the rate of relaxation, was prolonged in the AS2 group. In contrast, mitral valve opening pressure (MVOP) was significantly higher in this group than in the other two groups. The constant of left ventricular chamber stiffness was slightly but not significantly greater in both AS groups than in the control subjects. After surgery in patients in the AS1 group, preoperatively reduced %V1 had increased and preoperatively enhanced PFR2 had decreased. In patients in the AS2 group, excluding one with a persistent low ejection fraction after surgery, preoperatively enhanced PFR1 decreased in association with a decrease in MVOP. Thus, left ventricular filling dynamics vary in patients with AS depending on the degree of left ventricular hypertrophy and systolic function. In patients with AS and moderate hypertrophy %V1 is slightly reduced but is compensated for by a forceful atrial contraction. In those with severe hypertrophy and systolic dysfunction increased driving pressure allows %V1 to remain within normal limits, despite prolonged left ventricular relaxation and decreased elastic recoil. Both changes in left ventricular filling dynamics tend to normalize after surgery in association with a reduction in left ventricular hypertrophy and/or an improvement of systolic function.

Adult↗
PubMed1986

Myocardial relaxation and passive diastolic properties in man.

We have developed a model for assessing the influence of the decaying contractile systolic tension on diastolic wall dynamics and the passive properties of left ventricular muscle. Total measured left ventricular diastolic pressure and stress (sigma T) are determined by two overlapping processes: the decay of actively developed pressure and stress (sigma A) and the buildup of passive filling pressure and stress (sigma*). The decaying contractile stress sigma A is formulated in terms of a relaxation pressure with a time constant (T) assessed during the isovolumic relaxation interval. By subtracting the contribution of sigma A from sigma T we obtain sigma*. With micromanometry, echocardiography, and cineangiography, total and passive stress-strain relations and strain rates were evaluated over the entire filling period in six normal control subjects and in seven patients with aortic stenosis. Elastic stiffness constants (k), the slopes of the linear passive stiffness vs sigma* relations, did not differ in the two groups over a common lower stress range (6/6 normal, k = 9.37 +/- 1.23; 7/7 aortic stenosis, k = 9.34 +/- 1.08). Over a higher sigma* range, transition into a much steeper linear region occurred, and k values were much larger (4/7 aortic stenosis, k = 28.76 +/- 2.02). When diastolic stress levels are elevated, passive stiffness-stress relations can be better described as bilinear, with a much greater wall stiffness constant in the higher than in the lower stress range. Dynamic effects of decaying systolic contractile wall stress components are important in the rapid filling phase in normal hearts as well as in those with aortic stenosis.

Angiocardiography↗