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Biomedical subjects

H Just

Publications and source records attributed to H Just.

At least 199 records · Page 11Linked to original sources
PubMed1991

[Incidence of tricuspid valve prolapse].

The incidence of tricuspid valve prolapse and its association with mitral valve prolapse was studied in 100 patients with right- and left-ventricular angiography. Coronary artery disease was present in 81 patients (pts), a dilative cardiomyopathy in 6 pts, and a hypertrophic cardiomyopathy in 2 pts. 11 pts were angiographically normal. A total of 27 pts had a tricuspid valve prolapse, and 15 pts had a mitral valve prolapse. In 19 pts prolapse of the tricuspid valve was isolated, and in 8 pts it was associated with a mitral valve prolapse. The associated finding of a prolapse of the tricuspid and mitral valve was statistically significant (p less than 0.02). Patients with a tricuspid valve prolapse experienced a higher right-ventricular ejection fraction (58 + 10 vs 53 +/- 10%; p less than 0.05) and smaller end-systolic right ventricular volume indices (39 +/- 16 vs 47 +/- 17 ml/m2; p less than 0.05) compared to those without tricuspid valve prolapse. There was no further difference in clinical and hemodynamic parameters between those with and those without tricuspid valve prolapse. The clinical significance of a tricuspid valve prolapse is still undefined.

Adolescent↗
PubMed1990

Echocardiographic evaluation of patients with clinically suspected arterial emboli.

153 patients (mean age 42 years, range 16-60) who had arterial embolic events were examined prospectively by transthoracic and transoesophageal echocardiography. Patients older than 60 years and those with evidence of extracranial carotid artery occlusive disease were excluded. 84 patients had a cerebral ischaemic event, 50 patients had embolic events in an abdominal organ or limb, and 19 patients had acute retinal ischaemia. The transthoracic echocardiographic examination was normal in 92 patients (60%), whereas only 65 patients (42%) had normal findings after both transthoracic and transoesophageal examination (p less than 0.005). Intracardiac masses, including valvular vegetations, were found in 39 patients (25%), including 27% of patients with cerebral embolism and 32% of these with peripheral embolism, but in none of the patients with retinal ischaemia (p less than 0.001). 47 patients (31%) had valvular disease, 10 (7%) had wall motion abnormalities, 23 (15%) had abnormalities of the interatrial septum, and 9 patients (6%) had diseases of the thoracic aorta. Cardiovascular abnormalities were frequently found by echocardiography in patients with arterial emboli. The transesophageal technique significantly increased the chance of detecting such abnormalities, especially intracardiac masses.

Adolescent↗
PubMed1990

[The thrombolytic treatment of acute and subacute recurrent pulmonary embolism with recombinant tissue plasminogen activator].

Thrombolytic treatment with recombinant tissue plasminogen activator (rt-PA) at a dosage of 40-150 mg was given to five patients with acute and five with recurrent pulmonary emboli (three women and seven men; mean age 54 [30-78] years). Mean pulmonary artery pressure fell from 29 +/- 7 mm Hg before to 20 +/- 5 mm Hg after treatment (P = 0.001), and in recurrent emboli from 47 +/- 19 to 18 +/- 10 mm Hg (P = 0.01). Pulmonary vascular resistance fell from 546 +/- 262 to 318 +/- 116 dyn.s.cm-5 (P = 0.02) in the former group and from 993 +/- 583 to 377 +/- 438 dyn.s.cm-5 (P = 0.01) in the latter. Pulmonary arteriograms were assessed using the Miller index. This indicated a drop from an average of 23 points before to an average of 10.5 points after treatment. Mild bleedings occurred in all patients, but in two it was severe enough to require discontinuation of treatment. These results demonstrate that rt-PA is highly effective as a thrombolytic agent in acute and in subacute recurrent pulmonary embolism.

Acute Disease↗
PubMed1990

[The role of ACE-inhibition in the therapy of chronic heart insufficiency].

It is now established that ACE-inhibitors are effective in the treatment of severe chronic heart failure; in addition to digitalis and diuretics. Furthermore, recent studies suggest, that beneficial effects of ACE-inhibitors can be expected in patients with moderate heart failure: when combined with diuretics. In atrial fibrillation, the combination with digitalis is recommended. Up to now, there is no clear evidence that monotherapy with ACE-inhibitors is superior to first line therapy with diuretics or digitalis. Nevertheless, initial (and limited) experience favors the use of ACE-inhibitors to prevent progressive LV-dysfunction following myocardial infarction. Based on experimental data, several additional mechanisms of action (besides unloading the heart) have been proposed; which may open up new indications for ACE-inhibition, such as antiarrhythmic, antiischemic or antiproliferative effects (including decreased incidence of coronary restenosis following angioplasty). If confirmed by clinical studies, the indications for ACE-inhibitors will expand considerably, putting emphasis on prevention of occurrence and progression of heart failure rather than treatment of very late stages of chronic heart failure. Yet, the Consensus trial demonstrated a significant impact of these agents on mortality in the latter patient population.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1990

Repeat determination of left ventricular wall thickness from mass and volume during one cardiac cycle for the calculation of left ventricular wall stress parameters.

Left ventricular end-diastolic wall stress, end-systolic wall stress, and systolic stress-time integral are important parameters to characterize left ventricular load and function. To obtain these parameters, left ventricular pressure, volume, and wall thickness data must be determined at short time intervals throughout one cardiac cycle. However, the measurement of wall thickness at short intervals (i.e., 20 ms) throughout a cardiac cycle is tedious. Furthermore, measurements of wall thickness are less accurate at end-systole compared with end-diastole. For these reasons we developed a computer program for calculating wall thickness at short intervals (20 ms) throughout the cardiac cycle from one single determination of left ventricular wall mass and repetitive measurements of left ventricular (LV) volume.

Computer Simulation↗
PubMed1990

Lidocaine in the early phase of acute myocardial infarction: the controversy over prophylactic or selective use.

In acute myocardial infarction, lidocaine is considered the drug of choice for the treatment of malignant ventricular arrhythmias. While initially a so-called "selective" treatment strategy prevailed, in which lidocaine was administered only after the onset of certain "warning arrhythmias," the prophylactic use of lidocaine in acute myocardial infarction has been gaining wider usage in intravenous and intramuscular application in recent years. Both therapeutic applications have been found to be problematic of late, which has led to increasingly restrictive use of lidocaine. While in selective treatment forms, the definition and prompt recognition of the so-called warning arrhythmias created especially acute problems, the prophylactic therapeutic use is problematic due to the occurrence of sometimes serious side effects, which is to be expected as the size of the collective being treated increases. Both treatment forms also appear limited by the narrow preventive efficacy of lidocaine against malignant ventricular arrhythmias, especially against ventricular fibrillation. The current therapeutic recommendation for lidocaine in acute myocardial infarction should be limited to patients presenting with very frequent and complex ventricular arrhythmias, especially when these are elicited by an R-on-T phenomenon. Side effects and other therapeutic problems encountered when the therapeutic modality is switched or adjusted can be greatly reduced by careful dosing and selection of the optimal combination substances.

Acute Disease↗
PubMed1990

Treatment with diltiazem preoperatively in open heart surgery for myocardial protection: experimental studies in dogs with chronic healed myocardial infarction.

Calcium antagonists have become important in open heart surgery because of their effects on myocardial protection and cardioplegia. We evaluated the effect of pretreatment with the calcium antagonist diltiazem for myocardial protection in dogs with experimentally induced, chronic, healed myocardial infarction in a double-blind randomized study. One group consisted of 5 dogs treated with diltiazem (10 mg/kg bodyweight) for 7 days preoperatively, while a second group of 4 dogs were treated with placebo. All animals then underwent hypothermic, ischemic cardiac arrest (90 min) with extracorporeal circulation (ECC), followed by 30 min of reperfusion. Hemodynamic parameters were measured before and after ECC. An EKG was recorded during the entire procedure. The myocardium was studied by light microscopy for fresh necroses. The old, experimentally induced infarction scars were quantified by a new method that was developed for planimetry of the histological specimens. The diltiazem group compared with the placebo group showed myocardial cell necroses to a smaller extent. The hemodynamic studies supported the contention that diltiazem given preoperatively has a myocardial protective effect. These results encourage further studies on the use of diltiazem preoperatively for myocardial protection.

Animals↗
PubMed1990

An epidemiological study assessing the relative importance of airborne and direct contact transmission of microorganisms in a medical intensive care unit.

A prospective epidemiological survey was carried out over a period of seven weeks in a medical intensive care unit. Bacteria from patients, staff and air were monitored and the transmission of isolated microorganisms was followed. Handwashing samples revealed pathogenic bacteria in 30.8% of physicians (average number of colony forming units: 71,300 per hand) and 16.6% of nurses (39,800 cfu per hand). Air cultures yielded pathogens in 15% of sampling periods and nine of 53 patients were found to be colonized with Gram-negative bacteria, Staphylococcus aureus or Candida spp. The spectrum of bacteria recovered from patients and air was generally different, whereas strains recovered from patients and their attendants' hands were indistinguishable on multiple occasions. The results of this study confirm that direct contact is the principal pathway of microbial transmission, whereas little evidence for a significant role of airborne transmission is shown. The call for more extensive air-filtering and ventilation systems in medical intensive care units is not supported by the results shown in this communication.

Air Microbiology↗
PubMed1990

Coronary reperfusion studies with pro-urokinase in acute myocardial infarction: evidence for synergism of low dose urokinase.

Pro-urokinase is a single chain precursor of two chain urokinase, which has been shown to induce fibrin-selective plasminogen activation. In the present study, thrombolytic efficacy of 9 million U of glycosylated pro-urokinase administered intravenously was compared with that of a combined regimen utilizing 4.5 million U of pro-urokinase and 0.2 million U of urokinase. Seventy-five patients with a first myocardial infarction were randomized to receive high dose pro-urokinase (n = 40, group A) or the combination therapy (n = 35, group B). Reperfusion of the infarct-related artery was assessed by repeat coronary angiography. Thrombolysis in Myocardial Infarction trial (TIMI) grade II or III reperfusion was achieved in 73% of group A patients compared with 66% of group B patients (p = NS). A trend toward faster reopening of the infarct-related artery was observed in patients in group B. Coronary artery reocclusion occurred in 5 (10%) of 49 patients in whom angiography was repeated within 36 h after the start of therapy. Clot-selective thrombolysis was indicated by a minimal fibrinogen decline (15% and 13%, respectively, in groups A and B). Alpha 2-antiplasmin levels, however, decreased more rapidly in patients in group B (p less than 0.05). This finding and the equivalent reperfusion rate in the combined treatment group strongly suggest synergistic interaction between these two thrombolytic agents. In summary, the high incidence of reperfusion, the low rate of early reocclusion and the paucity of side effects, particularly with regard to bleeding complications, indicate that pro-urokinase possesses the characteristics of an ideal thrombolytic agent.

Drug Synergism↗
PubMed1990

ECG variants and cardiac arrhythmias in athletes: clinical relevance and prognostic importance.

These findings permit the following conclusions on cardiac changes induced by high-performance sports and high levels of training. Sinus bradycardia and AV block can frequently be observed in athletes, but they do not require attention as long as they are asymptomatic or do not produce pauses exceeding 4 seconds. Persistent rather than transient second-degree AV block or Mobitz second- or third-degree AV block is an extremely unusual finding even in athletes and should be considered a sign of organic lesions until proved otherwise. Supraventricular and AV node ectopic beats are not more frequent in athletes than in the general population except for atrial fibrillation. WPW syndrome is of particular importance, since rapid conduction to the ventricle via the accessory AV pathway is possible, especially if there is a tendency toward atrial fibrillation. Likewise caution is required in athletes with hypertrophic cardiomyopathy. Here hemodynamic deterioration must be anticipated with the occurrence of supraventricular tachycardia. Simple ventricular arrhythmias occur among athletes with the same frequency as in the general population, but they usually disappear with exercise. The occurrence of complex ventricular forms of arrhythmia should always prompt cardiologic examination in search of underlying cardiac disease, particularly hypertrophic or dilated cardiomyopathy. The presence of ventricular arrhythmias without evidence of underlying heart disease does not indicate a special or increased risk of sudden cardiac death. A higher incidence of right and/or left ventricular hypertrophy, exercise-reversible ST elevation, and exercise-reversible changes in T waves (T negativity, sharp and/or excessive T waves) can be considered physiologic changes in the ECGs of athletes. These changes correlate closely with the type of sports activity and degree of training and are reversible when the activity is stopped. Horizontal ST segment depression are by contrast very rare in athletes and should always be clarified by cardiologic examination. Exercise-induced sudden cardiac death in athletes is unusual without preexisting heart disease. The cause of sudden cardiac death among athletes less than 40 years of age can be predominantely ascribed to congenital heart diseases (such as hypertrophic cardiomyopathy or coronary anomalies). In athletes more than 40 years of age and with increasing age, coronary heart disease is the most frequent autopsy finding. A corresponding risk stratification should take these partial dangers into account.

Arrhythmias, Cardiac↗
PubMed1990

Detection of traumatic myocardial injury by means of simultaneous Tl-201/Tc-99m pyrophosphate tomography--report of three cases.

Trauma to the chest can result in cardiac damage, which may be missed by clinical examination because of associated injuries. Routinely performed non-invasive tests may also be non-diagnostic. Tc-99m pyrophosphate (PPi) tomography, in this study combined with Tl-201, is a promising addition to non-invasive evaluation. In three patients with cardiac injury, this technique successfully detected and localized myocardial necrosis.

Adult↗
PubMed1990

Acute myocardial infarction delineated by noninvasive thallium-201/technetium-99m pyrophosphate tomography.

The purpose of this study was to validate different scintigraphic approaches for assessing acute myocardial infarctions. 201Tl, 99Tcm pyrophosphate (PPi) and combined 201Tl/99Tcm PPi tomograms were evaluated in 115 consecutive patients, in 85 of whom clinical examination revealed acute myocardial infarction. The overall sensitivity and specificity for infarct detection was 80% versus 56% for 201Tl alone, 61% versus 97% for 99Tcm PPi alone, and 100% each for the combined 201Tl/99Tcm PPi imaging. The sensitivity for nontransmural infarcts was 57% for 201Tl, 37% for 99Tcm PPi and 100% for combined imaging. The overlay of 201Tl and 99Tcm PPi images increases the observer's confidence in the diagnosis and provides better localization of the infarction. 201Tl alone could localize the infarction in 80%, 99Tcm PPi alone in 49% and 201Tl/99Tcm PPi in 100% of the cases. ECG and 201Tl/99Tcm PPi tomography concurred upon infarct localization in 98% of the patients. Based on the 201Tl/99Tcm accumulation pattern, 94% of the Q-wave infarctions were judged to be transmural and 83% of the non-Q-wave infarctions were judged to be nontransmural. It is concluded that combined 201Tl/99Tcm PPi tomography is highly accurate for determining the presence and location of acute myocardial infarction. This technique appears to be superior to studies where only one radioisotope is used.

Adult↗
PubMed1990

The safety profile of ibopamine, an alternative substance for treatment of chronic heart failure.

Before a new drug can be recommended for treatment of chronic heart failure, efficacy and safety have to be fulfilled. In this paper, the safety aspect of ibopamine, a congener of dopamine, is investigated by reviewing the available reports on this drug. A trend towards reduced mortality was found for patients with chronic heart failure during long-term treatment. No change in the potassium serum concentration has been found, whereas the plasma renin activity, plasma norepinephrine levels and the aldosterone secretion were decreased. It is concluded that ibopamine is a safe drug which may become an interesting alternative or additive therapy for patients with chronic heart failure.

Cardiotonic Agents↗
PubMed1990

Vasodilatory action of endogenous atrial natriuretic factor in a rat model of chronic heart failure as determined by monoclonal ANF antibody.

Elucidation of the role of (elevated) endogenous atrial natriuretic factor (ANF) in chronic heart failure has been hampered by a lack of specific inhibitors. We used a newly developed monoclonal antibody that has been shown to specifically block both exogenously and endogenously released ANF in vivo. For assessment of the vasodilatory action of ANF in chronic heart failure, either this antibody against ANF or ascites (control serum) was injected in rats with myocardial infarction and failure and in sham animals. Ascites did not alter central hemodynamics in either the sham or infarcted group. Antibody significantly increased right atrial pressure, left ventricular end-diastolic pressure, and systemic vascular resistance (SVR) in the infarction group but did not affect these variables in the sham group. Because renal blood flow, as measured by radioactive microspheres, decreased significantly in all four groups, probably due to nonspecific renal vasoconstrictor effects of the ascites, a separate group of infarcted animals was treated with purified ANF antibody (devoid of nonspecific effects) or mouse IgG as a control injection. In these animals, right atrial pressure increased from 1.1 +/- 0.7 to 2.6 +/- 0.7 mm Hg (p less than 0.001). Although SVR, renal blood flow velocity (measured by Doppler probe), and renal vascular resistance did not change in the infarcted animals after administration of purified ANF antibody, a significant correlation was found between baseline plasma ANF values and the change in SVR exerted by purified ANF antibody (r = 0.758, p less than 0.02, n = 9); that is, SVR increased in rats with high baseline plasma ANF (greater than 350 pg/ml), but decreased in animals with plasma ANF less than 200 pg/ml. These results suggest that moderately elevated endogenous plasma ANF levels in chronic heart failure do affect central hemodynamics, primarily by reducing venous pressure (e.g., by decreasing intravascular volume or by venous dilation). Arterial vasodilation, however, appears to emerge when plasma ANF is greatly increased.

Animals↗
PubMed1990

Reocclusion prophylaxis with dipyridamole combined with acetylsalicylic acid following PTA.

After primary successful PTA, 199 patients were randomized into one of three treatment groups, namely, placebo or a combination of 75 mg dipyridamole with either 330 mg (high dose) or 100 mg (low dose) acetylsalicylic acid (ASA) tid. The duration of treatment was six months. Of the 199 patients admitted to the study, 156 completed the six-month trial period. Not all patients had a second angiogram, and in these cases clinical findings were used in the evaluation. Evaluation of the combined angiographic and clinical results showed improvement or no deterioration in 37% of patients in the placebo group compared with 49% in the low-dose and 61% in the high-dose ASA groups respectively. The only statistically significant difference observed was between the placebo group and the group treated with dipyridamole and high-dose ASA (p = 0.01). This difference remained statistically significant at p = 0.039 if only the angiographic findings were considered for group comparison. It cannot, however, be concluded from this study that 75 mg dipyridamole in combination with 100 mg ASA tid is more effective in preventing reocclusion after PTA than in combination with 330 mg ASA tid.

Adult↗
PubMed1990

Beta-blocking agents vs. antiarrhythmic interventions in heart failure complicated by arrhythmias.

Approximately 40-50% of the patients with end-stage cardiac failure (either ischemic or nonischemic) die suddenly and unexpectedly, most probably from ventricular fibrillation. It is unclear whether the complex ventricular arrhythmias observed in large numbers of these patients were related to the mode of death. Theoretically, it seems quite reasonable to attempt to suppress the development of life-threatening ventricular arrhythmias (e.g., sustained ventricular tachycardia or ventricular fibrillation) in those patients. If antiarrhythmic drug therapy is ineffective, alternative antiarrhythmic interventions (antiarrhythmic surgery or implantation of an automatic implantable cardioverter defibrillator) should be considered. In patients with so-called potentially malignant ventricular arrhythmias (e.g., nonsustained ventricular tachycardia), antiarrhythmic drug therapy remains controversial as presently there is no definitive proof that this therapy prolongs life or reduces the incidence of sudden cardiac death. In patients with end-stage cardiac failure, beta-blockade can result in a decrease in resting tachycardia, improvement in clinical heart failure symptoms, and increase in work load capacity. It remains controversial whether treatment with these agents can also improve prognosis and prevent sudden cardiac death. Therefore, at this time, only patients in the earlier stages of this clinical syndrome and with clinical signs of markedly increased sympathetic tone can be treated with low doses of beta-blockers.

Adrenergic beta-Antagonists↗
PubMed1990

Modulation of myothermal economy of isometric force generation by positive inotropic interventions in the guinea pig myocardium.

Isometric force development has been measured simultaneously with liberated heat in papillary muscles from the right ventricle of the guinea pig, using rapid antimony-bismuth thermopiles. The following components of the contractile cycle and their relation to energy consumption were evaluated: (1) basal metabolism; (2) crossbridge cycling; (3) calcium cycling; and (4) recovery processes. The influences of isoproterenol, high calcium and UDCG-115, a calcium-sensitizing substance, on these four energy compartments of the muscle were studied relative to their positive inotropic effects. Isoproterenol increased initial heat per peak developed tension or per tension-time integral from 7.4 +/- 1.55 to 11.65 +/- 1.15 mucal/g cm (p less than 0.02) or from 4.52 +/- 0.79 to 8.14 +/- 0.77 mucal/g cm sec (p less than 0.01), respectively. In contrast, these ratios were unchanged from control values by positive inotropic interventions with 11 mM calcium or UDCG-115. The increase of initial heat for a unit of mechanical activity due to isoproterenol is attributable to activation and contractile protein processes, i.e. the activation heat increased from 0.24 +/- 0.05 to 0.68 +/- 0.13 mcal/g (p less than 0.01) and tension-dependent heat per tension-time integral increased from 2.24 +/- 0.60 to 5.18 +/- 0.89 mucal/g cm sec (p less than 0.01). We conclude that isoproterenol increases the number of calcium ions released into the sarcoplasm during each activation cycle. It also alters the rate of crossbridge cycling associated with a decreased economy of force generation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗