Effect of stenotic geometry on flow behaviour across stenotic models.
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Arterial Occlusive Diseases↗
Biomedical subjects
H Just
Publications and source records attributed to H Just.
Estimation of left ventricular volume and mass by magnetic resonance imaging: comparison with quantitative biplane angiocardiography.
Magnetic resonance imaging (MRI) is well suited for the delineation of cardiac anatomy. In this study an estimation of left ventricular volume and muscle mass by MRI was attempted, using an iron-shielded resistance magnet (Bruker) with 0.23 T. Images were obtained with ECG gating. For image-processing our own software program was used. Slice images were 8 mm thick and spaced 16 mm. Volumes were standardized for a "normal" LV. Muscle mass was calculated directly from the systolic image as the difference between inner and outer ventricular outline. There was a wide range of volumes and mass (100-300 ml, 200-500 g). For comparison and validation conventional biplane left ventriculography was used. Fourteen patients were studied with MRI, but satisfactory studies were obtained in only 7. Correlation of MRI and angiographic volumes was good (r = 0.84). For left ventricular mass it was excellent (r = 0.94). Ventricular walls and cavities were clearly outlined. Even minor details of anatomy were recognized. Limitations of MR study included a narrow space for the patient within the system and the long duration of data acquisition time.
Adult↗
Prospects for the use of ACE inhibitors in patients with coronary artery disease.
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Angiotensin-Converting Enzyme Inhibitors↗
Central and regional vascular hemodynamics following intravenous milrinone in the conscious rat: comparison with dobutamine.
This study examined the hemodynamic and regional vascular profile of intravenous (i.v.) milrinone during increasing doses (3, 6, 12 micrograms/kg/min, n = 8) and by intraindividual comparison of milrinone and dobutamine (n = 10) in normal conscious rats. At 3 micrograms/kg/min, Milrinone increased coronary and cerebral blood flow (radioactive microspheres 15 +/- 5 microns) (7.7-9.8 and 1.05-1.27 ml/min/g respectively, both p less than 0.05) without significant changes in systemic hemodynamics. At 6 micrograms/kg/min milrinone increased skeletal muscle blood flow (0.19-0.24 ml/min/g, p less than 0.05) along with increases in cardiac output, stroke volume, and stroke work (all p less than 0.05), while systemic vascular resistance decreased (-51%, p less than 0.05). When compared with dobutamine, milrinone caused a greater increase in cardiac output (+26% vs. +17%) and a greater reduction in systemic vascular resistance. Milrinone and dobutamine increased renal, intestinal, cerebral, and coronary flow to a similar extent, but only milrinone enhanced hepatic arterial blood flow (+26%, p less than 0.05) and tended to increase flow to skeletal muscle (+35%, p = 0.07). We conclude that milrinone exerts significant regional vasodilating effects in a conscious rat model, being most prominent in the coronary and cerebral circulations at a dosage that does not alter central hemodynamics. At higher doses, milrinone causes a balanced increase in regional blood flow including enhanced flow to skeletal muscle. The hemodynamic (particularly as compared with dobutamine) and regional vascular profile of milrinone suggests a predominant vasodilating effect in the rat. Given a similar limited response of rat and diseased human myocardium to milrinone, these findings may have important clinical implications.
Animals↗
Hierarchy of levels of ischemia-induced impairment in regional left ventricular systolic function in man.
We tested the hypothesis that different subsets of ischemia-induced wall motion disorders are characterized by specific patterns of abnormal regional left ventricular systolic function. Regional contraction was quantitatively assessed from two-dimensional echocardiograms by an automated integrative analysis considering the time course of wall motion during the entire contraction sequence in 20 patients with chronic myocardial infarction, in 13 patients with impending myocardial infarction (less than 2 hr after the onset of symptoms), and in nine patients during transient myocardial ischemia. Wall motion abnormalities were detected in all patients by the integrative analysis. In contrast, the sensitivity for detecting wall motion abnormalities was 80% during chronic infarction, 77% during impending infarction, and 56% during transient ischemia if only end-diastolic and end-systolic frames were compared for assessment of overall regional systolic function. There were distinct differences in the time course of abnormal wall excursion between the three groups. Chronic infarction was characterized by a monophasic contraction pattern, with abnormal synergy in regional contractile events occurring predominantly during early systole. In contrast, transient ischemia caused predominantly mid-to-late systolic abnormal synergy followed by late systolic shortening corresponding to a polyphasic contraction pattern. During impending infarction, an intermediate temporal contraction pattern was present with both early and mesosystolic abnormal synergy.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Blood flow distribution within skeletal muscle during exercise in the presence of chronic heart failure: effect of milrinone.
Recent studies suggest that, in the presence of heart failure, the capability of skeletal muscle to utilize delivered flow may be impaired due to maldistribution of blood flow within working muscle. Similarly, this mechanism could explain the failure of drugs to improve maximal oxygen consumption (VO2max) immediately. Accordingly, we assessed muscular blood flow distribution (ml/min/g, radioactive microspheres, 15 +/- 5 micron) among and within working muscle, VO2max, and arterial lactate in a rat preparation of myocardial infarction and heart failure (infarct size 36.0 +/- 3.3% of the left ventricle, n = 9), and in sham-operated animals (n = 11). Data were obtained at maximal treadmill exercise during alternate infusions of milrinone and saline. Total skeletal muscle blood flow during exercise was significantly lower in the infarction group (p less than .05 vs sham); reduced blood flow was primarily attributed to decreased flow to oxidative working muscle such as soleus and the red portion of gastrocnemius, whereas blood flow to glycolytic muscle portions (e.g., gastrocnemius white, vastus lateralis white) was similar in the infarction and sham-operated groups. Milrinone increased flow to the glycolytic working muscle portions in sham-operated animals (e.g., vastus lateralis white, 0.23 vs 0.29, p less than .05); by contrast, blood flow to the oxidative muscle fibers was increased in the infarction group (e.g., gastrocnemius red, 1.45 vs 1.87, p less than .05). Arterial lactate levels at similar workloads during exercise were higher in the infarction group (p less than .05). Neither lactate nor VO2max were significantly altered with milrinone in either group.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[Hemodynamic effects of serially arranged model stenoses (tandem stenoses )].
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Coronary Artery Disease↗
Early clinical evaluation of the intravenous treatment of acute myocardial infarction with anisoylated plasminogen streptokinase activator complex.
50 consecutive patients with acute myocardial infarction and symptoms of less than 4 hours duration were treated with anisoylated plasminogen streptokinase activator complex (APSAC) 30U intravenously as a bolus injection over 5 minutes. An open infarct-related artery was found in 32 patients (64%) when the first coronary angiography was taken 66 +/- 21 minutes after APSAC. Complete reperfusion was subsequently seen in 10 of 18 patients with an occluded infarct-related artery 74 +/- 16 minutes after injection of APSAC. Thus, a patient infarct-related artery was seen in 42 patients (84%) within 68 +/- 20 minutes. A control coronary angiography was performed in 37 patients (74%) after 25 +/- 19 days. Reocclusion was found in 5 patients. The minimal cross-sectional area of the residual coronary stenosis increased from 1.3 +/- 0.9 mm2 to 1.8 +/- 1.9 mm2. Patients with residual thrombi after coronary thrombolysis (n = 13) demonstrated an increase of the minimal cross-sectional area of the residual stenosis from 1.2 +/- 0.8 to 2.6 +/- 2.3 mm2, whereas those without residual thrombi showed only minor changes of the minimal cross-sectional area (1.3 +/- 0.9 to 1.2 +/- 1.2 mm2). Thus, APSAC demonstrated a high patency rate and a low reocclusion rate after intravenous administration. The prolonged fibrinolytic activity of APSAC leads to a further regression of the residual coronary stenosis among patients with coronary thrombi after reperfusion.
Adult↗
[Relation between spontaneous and electrically inducible ventricular arrhythmias in patients with coronary heart disease].
In a prospective study, 267 patients with invasively diagnosed coronary artery disease were studied by programmed electrical stimulation (PES) and induced ventricular arrhythmias were compared to spontaneous arrhythmias occurring during 24 h Holter registration. In 89 patients (33%) no evidence of myocardial infarction was present, 61 patients (23%) were studied for 6 weeks to 3 months, 36 patients (13%) for 3-6 months and 81 patients (31%) for more than 6 months after myocardial infarction. PES was performed in the right ventricular apex with 1 and 2 extrastimuli during pacing with 100, 120 and 140 beats/min. Endpoint of the study was defined by the induction of 4 repetitive ventricular responses (RVR). Within 72 hours after PES a 24 h Holter registration was performed in all patients. During PES, 15 patients (6%) were not inducible for any RVR. Single RVR (1-2) were induced in 146 patients (55%) and 3-5 RVR in 68 patients (25%). Ventricular tachycardia and ventricular fibrillation were induced in 38 patients (14%); 6 patients showed a sustained, monomorphic tachycardia. Altogether, the incidence of RVR was higher when a history of myocardial infarction was present. With increasing time after infarction the incidence of inducible 3-5 RVR remained stable; however, the number of greater than 6 RVR decreased. During Holter registration, 54/255 patients (21%) showed no spontaneous ventricular arrhythmias, 70 patients (28%) had arrhythmias of Lown-class I/II, 84 patients (33%) of Lown-class III. Complex arrhythmias were observed in 47 patients (18%) (Lown-class IVA: 33 patients, IVB: 14 patients).(ABSTRACT TRUNCATED AT 400 WORDS)
Adult↗
[Anti-arrhythmia effectiveness and tolerance of retard in comparison with standard mexiletine].
In a controlled randomized cross-over trial, 21 patients with coronary artery disease and frequent ventricular arrhythmias were studied to test the efficacy and tolerance of mexiletine 200 mg t.i.d. in comparison to a released application form of mexiletine perlongettes 360 mg b.i.d. During 24-hour Holter monitoring, all patients but one showed more than 30 ventricular premature beats/h; additionally, in 16 patients, complex ventricular arrhythmias (Lown class IV) were documented. In all patients each medication was given for 5 days. Before treatment and during both medication periods, a 4 days' wash-out period was interposed. Mexiletine and mexiletine perlongettes each resulted in a suppression of ventricular ectopy of more than 84% in 10/21 patients (47%); in two patients the response was different. The mean reduction rate in all patients was 68% for mexiletine and 64% for mexiletine perlongettes. In the responder group, the mean reduction rate amounted to 95% under both medications. Ventricular pairs and tachycardia were reduced by more than 90%. Plasma concentration under mexiletine perlongettes was slightly higher, as compared to the standard form of mexiletine; however, under mexiletine, significant changes of plasma concentration were observed during the day only when the standard form was used. Side effects were observed in 8/21 patients (38% for mexiletine) and in 5/21 patients (24% for mexiletine perlongettes). These were mainly gastrointestinal or neurological, but were mild in all patients and did not necessitate discontinuation of the medication in any patient.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
The sliding rail system (monorail): description of a new technique for intravascular instrumentation and its application to coronary angioplasty.
The sliding rail technique is a new technique for intravascular instrumentation, especially coronary stenosis dilatation. The so-called monorail balloon catheter is the first device which can be used according to this technique. The monorail catheter has a single lumen shaft and only a short central tube within the distal balloon part. With the guidewire inserted into the tube, the balloon can be advanced or retracted on the guidewire as on a sliding rail. The most relevant improvements for coronary dilatation are steerability, contrast flow and rapid and easy exchangeability of balloon catheters and other intracoronary devices. These characteristics are felt to result in a more simple and time- and fluoroscopy-saving dilatation procedure. A special transfusion catheter may also improve procedural safety. The first clinical results in 69 patients with a success rate of 96%, an emergency bypass rate of two patients (one infarction) and a stenosis improvement of 58% confirm the theoretically conceived advantages.
Adult↗
[Acute effects of nitroglycerin on the energetics of the human left ventricular myocardium].
We analyzed performance and efficiency of the left ventricular myocardium on the basis of two new energetic parameters. The myocardial energy consumed during one cardiac cycle is related to performed work on the one hand (E1) and to the stress-time-integral on the other (E2). E1 was obtained by analysis of the pressure-volume integral divided by left ventricular muscle mass. E2 was obtained as follows: the stress-time integral was analyzed from pressure-volume data and wall thickness using an ellipsoidal calculation model. In order to transfer the stress-time integral into energy units, the value was multiplied by a constant factor which was obtained in experimental myothermal studies. In ten patients with coronary heart disease undergoing diagnostic heart catheterization, angiocardiography was performed before and after oral administration of nitroglycerin (1.6 mg). Total energy consumption (2E1 + E2) per gram myocardium per beat decreased from 6.1 +/- 1.3 mcal/g to 4.7 +/- 1.4 mcal/g (P less than 0.01), and myocardial efficiency (E1/[2E1 + E2]) increased from 27.0 +/- 3.1% to 28.4 +/- 4.3% (N.S.) on the average. This analysis explains quantitatively the beneficial effect of nitro-preparations on myocardial function and energetics.
Adult↗
[Infection of the CNS caused by Listeria monocytogenes].
This report examines two cases of infection of the central nervous system by Listeria monocytogenes (L.m.). Both cases show that listeriosis is not only a differential diagnosis of purulent meningitis, but can also be the cause of an isolated brain stem syndrome with normal cerebrospinal fluid cell count. The prognosis depends crucially on the early antibiotic therapy (ampicillin). The first patient was a chronic alcoholic. He died of fulminant septic shock and meningitis with brain stem encephalitis (cell count of cerebrospinal fluid: 10500/microliters). L.m. was isolated from blood cultures and from cerebrospinal fluid. The second patient had no indications of preexisting immunological disorder. Two days after perianal injections for haemorrhoids, symptoms of a progredient brain stem syndrome developed. The cell count of cerebrospinal fluid was only 10/mu, but L.m. was isolated from blood cultures. The patient died of circulatory failure. At autopsy, a brain stem encephalitis and cerebellitis with inflammation of the surrounding leptomeninx was identified.
Cerebral Ventricles↗
[Prognostic significance of ventricular arrhythmia in dilated cardiomyopathy].
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Arrhythmias, Cardiac↗
[Central and regional vascular hemodynamics of milrinone in experimental heart failure: comparison with captopril and dobutamine].
The present study was designed to evaluate the regional vascular profile of milrinone in the setting of experimental heart failure. Utilizing the rat model of myocardial infarction and failure (average infarct size 28%), we measured cardiac output (CO), arterial pressure (MAP), LVEDP, heart rate and systemic vascular resistance, as well as regional blood flow (radioactive microspheres 15 +/- 5 microns) before and after milrinone i.v. (20 microns/kg bolus, 3 micrograms/kg/min infusion) in the conscious state (LVEDP 22 mm Hg versus 10 mm Hg in the sham-operated group, p less than 0.01). Similarly, central hemodynamics and regional blood flow were determined before and after dobutamine or captopril, administering equipotent doses. Milrinone reduced LVEDP more than dobutamine, both more than captopril; MAP was decreased by captopril only. Although all three drugs reduced SVR to a similar extent and increased CO, a quite different blood flow distribution occurred. Improvement in flow to skeletal muscle and splanchnic circulatory bed was exerted by milrinone only. Thus, milrinone attenuated the vasoconstriction in those circulations known to be impaired in heart failure. In contrast to captopril, the effects of milrinone on renal perfusion were modest. These results demonstrate the potent vasodilator activity of milrinone, which is independent of its direct-positive inotropic effects, being most prominent in the splanchnic, coronary and skeletal muscle circulation. The latter might have clinical relevance since improved muscular flow during exercise is likely to improve exercise capacity in heart failure after long-term treatment.
Animals↗
[Treatment of heart failure: status of therapy with vasodilator agents].
Treatment of heart failure comprises the use of diuretics, vasodilators and inotropic substances. Unloading of the heart and the circulation in hydropic states is classically achieved with diuretics. The retention of salt and water in chronic heart failure requires chronic treatment with diuretics. This mode of treatment is basic to all forms of hydropic heart failure. Inotropic substances such as digitalis glycosides, sympathomimetic amines or phosphodiesterase inhibitors have certain disadvantages: Inotropic stimulation increases energy demand of the working heart muscle. Most of the substances used today increase energy consumption inordinately, thereby decreasing economy of myocardial contraction. This aspect calls for caution in the application of these substances in chronic heart failure, although they seem indispensable (sympathomimetic amines) in acute hypotensive failure and shock. Digitalis glycosides, basically suited for longterm treatment, exert only mild inotropic effects. In addition inotropic stimulation brings with it arrhythmogenic effects. All inotropic substances can induce ventricular arrhythmias already at therapeutic levels. Vasodilating substances have found increasing acceptance as a particularly useful and safe group of drugs for the treatment of heart failure. Nitrates: With the different nitrate compounds and nitrate preparations an effective venodilation with preload reduction can safely be achieved. At higher doses, arteriolar also dilatation can be induced. Although tolerance may be a problem with chronic application, this can be avoided with prudent dosing. The strong venodilating property makes these drugs together with their rapid onset of action ideally suited for the treatment of acute heart failure with pulmonary congestion.(ABSTRACT TRUNCATED AT 250 WORDS)
Angiotensin-Converting Enzyme Inhibitors↗
Radiological prerequisites for spatial intracoronary orientation and quantitation in interventional cardiology.
The prerequisite for the safe performance of an intracoronary intervention is an optimal angiographic visualization. This includes high resolution film and video equipment and the acquisition of spatial information about anatomic details during the procedure. The geometric properties of modern biplane multidirectional X-ray equipment allow for exact spatial computations. These can be used for optimal portraying of coronary segments by computed triple orthogonal projections. In addition, an improvement in quantitative angiography is possible by calculation of the exact radiological magnification factor of coronary stenosis.
Angiography↗
[The effect of stress ulcer prevention on the incidence of pneumonia in artificial respiration].
The role of stress ulcer prophylaxis in increasing the risk of pneumonia in ventilator patients was analyzed prospectively in 142 artificially ventilated patients at a medical and surgical intensive care unit (104 males, 38 females, mean time of ventilation 7.9 days, mean age 46.5 years). The pH of gastric aspirate and bacterial counts in gastric fluid and tracheal secretions were investigated daily. Identical isolates from gastric aspirates and tracheal secretions were typed by agglutination, bacteriocin, or phage typing. An average of 2.1 bacterial species were isolated in 80.5% of all gastric aspirates. Bacterial counts increased with rising gastric aspirate pH, which was especially true for Gram-negative and less so for Gram-positive organisms; colony counts of Candida sp. decreased slightly. In 31.6% of patients identical bacterial species were first isolated from gastric aspirates and 1 to 2 days later from tracheal secretions. Of these microbes that were first isolated from gastric aspirate and later from tracheal secretions, 50.3% were Gram-negative, 37.5% Gram-positive, and only 4.2% Candida sp. One-half of all bacterial aspirations occurred between the 2nd and 7th day of ventilation; 80% occurred within 11 days of ventilation. Only 20% of all migrations of Gram-positive organisms from stomach to respiratory tract lead to pneumonia, as compared with 60% of Gram-negatives. At a gastric pH below 3.4 the incidence of ventilation pneumonia was 40.6%; above pH 5.0 the incidence was 69.2% (P less than or equal to 0.05). As pH increased, the organism causing pneumonia was significantly more often isolated first from the gastric aspirate and 1 to 2 days later from the tracheal secretion of the same patient.
Anesthesia↗