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Biomedical subjects

P Niederle

Publications and source records attributed to P Niederle.

At least 19 recordsLinked to original sources
PubMed1992

[Incidence and changes in mitral regurgitation in balloon valvotomy of the mitral valve. A color Doppler study].

The objective of the work was a detailed examination of the incidence and changes of mitral regurgitation (MR) in conjunction with percutaneous transluminal valvotomy of the mitral valve (VMCH). Using coloured Doppler mapping, the authors examined a total of 40 patients before and in the course of one week after VMCH. They assessed the number of regurgitation jets the site of their development, the timing and haemodynamic impact of MR. Knowing the site of development of MR, the authors were able to assess whether the regurgitation after VMCH persisted, developed de novo or disappeared. The total number of mitral regurgitation increased after VMCH from 38 to 51 (increase by 34%, p < 0.05) with a significant rise of the number of double regurgitation jets (4 before as compared with 12 after VMCH, p < 0.05). Before VMCH the authors recorded a holocystic MR in 53%, after VMCH in 86% of the patients (p < 0.01). While before VMCH almost half the regurgitation jets originated in the central portion of the valve, after VMCH MR originated mainly from the area of commissures (48% regurgitation jets before, 79% after VMCH, p < 0.01). Only in 33% of MR after VMCH persisting regurgitation was involved, almost half (47%) of 38 regurgitation jets present before VMCH, disappeared after valvulotomy. MR displays a considerable variability. This may be one of the reasons why prediction of the development and severity of MR after PTMV is difficult.

Catheterization↗
PubMed1992

[The effect of isometric loading on diastolic left ventricular filling in healthy individuals studied by the Doppler technic].

The authors examined by Doppler echocardiography 30 subjects aged 21-30 years, exposed during examination to an isometric load by using a manual balloon dynamometer. The authors investigated different indicators of left ventricular filling during diastole and their indexes which evaluate indirectly the left ventricular diastolic function. The assessed correlations of some indicators with the quantitative expression of the isometric load (double product) were as follows: peak speed E - r = 0.3671 (p < 0.05), peak speed A - r = 0.6098 (p < 0.001), index of rations of peak speeds E/A - r = 0.6098 (p < 0.0001, sum of speed--time integrals TVIE + TVIA - r = 0.6469 (p < 0.001) and the time of retardation of the early filling phase of the left ventricle related to the heart rate DCT/TF - r = 0.7249 (p < 0.001). A statistically significant increase during the load was recorded in the peak speed A and a reduction of the E/A ratio (p < 0.01). The time speed integral TVIE increased (p < 0.01), both indexes TVI E + A and TVI E/A declined (p < 0.05). The time of retardation of the early filling stage to the early filling time DCT/DFT increased (p < 0.05) and DCT in relation to the heart rate DCT/TF declined significantly (p < 0.01). There was an insignificant decline of the peak speed of early filling E and its time-speed integral, TVI E. The sum of time-speed integrals TVIE + A did not change significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Clinical interpretation of the character of mitral valve flow in relation to diastolic properties of the left ventricle].

Based on their own experience and data in the literature the authors describe the Doppler method of evaluation of properties of the left ventricle. In patients with early disorders of the diastolic function, when above all relaxation of the left ventricle is affected, a reduced rate of early diastolic filling (E) is a typical finding. There is also compensatory increase in the rate of filling during auricular contraction (A) with the appropriate increase of the A/E ratio and the ratio of rate velocity integrals (TVIA/TVIE). At the same time the maximal flow through the mitral orifice is reduced during early diastole (PFR), the deceleration time is protracted and so is the time of isovolumic relaxation. For more advanced stages of cardiac damage when impaired compliance of the left ventricle predominates, typical features are the so-called restrictive type of filling with a high rate of E, short DT and a relatively low velocity A. There exists a number of intermediary types between these extreme types of flow. The final shape of the flow curve is influenced also by the actual haemodynamic condition of the subject (heart rate, pre-load, after-load, pressure in left, ventricle, left ventricular systolic function etc.). The authors draw therefore attention to possible errors during interpretation of assessed indicators. In the conclusion they recommend methodical principles for examination of left ventricular diastolic function by Doppler echocardiography. Above all it is necessary to respect restrictions due to valvular defects, arrhythmias, the action of drugs with haemodynamic action, the presence of signs of left ventricular failure, the influence of respiration on the flow rate, etc.

Blood Flow Velocity↗
PubMed1991

[The dipyridamole echocardiography test combined with isometric loading in the diagnosis of syndrome "X"].

Syndrome "X" comprises a heterogeneous group of patients with normal coronarographic findings whose repeatedly occurring chest pain is of ischaemic origin, similarly as angina pectoris in patients with CHD. One of the signs of ischaemic etiology of pain in these patients is significant depression of the ST interval on the ECG during ergometry. We were interested to know whether the depression of the ST interval and angina pectoris which develop during a load are associated also with a transient disorder of left ventricular local kinetics. We examined therefore five patients, using the dipyridamol test combined with an isometric load evaluated by two-dimensional (2D) echocardiography. All examinations revealed a normal coronarographic finding and significant electrocardiographic manifestations of ischaemia during ECG stress test. The investigation showed that none of the patients with "X" syndrome suffered from transient changes in the local kinetics of the heart muscle and we assume therefore that myocardial ischaemia in syndrome "X" does not affect a sufficiently large portion of the cardiac wall in the transmural section to be manifested by impaired kinetics detectable by 2D-echocardiography.

Adult↗
PubMed1991

Three echocardiographic methods in right ventricular function evaluation.

We employed two-dimensional echocardiography for the assessment of right ventricular (RV) volumes and/or function in a series of 44 patients. The results of three different echocardiographic approaches were compared with the data obtained from single-plane RV angiography following ultrasound within a 7-day interval. Only the echocardiographic area length method with two orthogonal imaging planes employed (apical 4-chamber and subcostal projections) yielded the beneficial results. The correlations between echocardiographic and angiographic RV volume estimates were rather high (end-diastolic volume: r = 0.83, end-systolic volume: r = 0.82, stroke volume: r = 0.81) and satisfactory in ejection fraction (r = 0.75). Using the method mentioned, the differentiation of patients with an angiographic evidence of RV failure (echocardiographic ejection fraction less than 0.55) from those without it was possible with a sensitivity of 0.68 and a specificity of 0.82. Concerning the clinical impact of the presented study, we can recommend the technique in question as a screening procedure for the detection of changes in RV function exceeding 12% (95% confidence limits).

Cineangiography↗
PubMed1991

The effect of acute and chronic nitrate administration in precapillary and postcapillary pulmonary hypertension.

The effect of nitrates was monitored in 16 patients with precapillary, and in 12 patients with postcapillary pulmonary hypertension (PH). The patients had haemodynamic examination on acute administration of 10 mg of isosorbide nitrate (ID) in infusion and after 2-month therapy with 120 mg of isosorbide dinitrate retard daily. Acute ID administration decreased filling pressure of both ventricles, pulmonary and aortic pressure, pulmonary and systemic resistance and increased blood flow. No significant difference was found between the two types of PH. Long-term administration resulted in a statistically significant decrease in filling pressure (in both ventricles) and pulmonary pressure, even though the decrease was less pronounced than those seen following acute administration. Again, no statistical differences were noted between the two types of PH. While acute administration of nitrates decreases both preload and afterload, chronic administration decreases only preload. The implications of this finding for therapeutic practice are discussed.

Cardiomyopathy, Dilated↗
PubMed1991

Doppler echocardiographic assessment of the diastolic properties of the cardiac ventricle in ischaemic heart disease.

The authors offer their experience with diastolic function assessment using Doppler echocardiography in ischaemic heart disease. Information on the diastolic properties of the ventricle is obtained from recordings of the blood flow velocity curve in mitral and tricuspid valve orifices. Doppler echocardiography, allowing to monitor the velocity curve of ventricular filling, represents one of the most modern techniques of examination. Diastolic function is commonly significantly affected by ischaemic heart disease, not only in terms of energy requirements; other factors such as the volume of venous return, extent of ischaemia, its time course, and so on, come into play. Changes in myocardial rigidity and filling pressures are two factors which exert a substantial effect on the character of inflow curves. The article describes typical recordings obtained from individual clinical manifestations of acute and chronic states in ischaemic heart disease, and reviews the still limited body of data regarding the effect of drug and/or surgical therapy on the diastolic properties of the affected ventricle.

Blood Flow Velocity↗
PubMed1991

[2-dimensional echocardiography in the evaluation of right ventricular volume and function. Comparison with echocardiography].

Using two-dimensional echocardiography (ECHO), the authors examined within one week preceding right-sided catheterization of the right ventricle (RV) 44 patients. Of three tested ECHO techniques for calculation of right ventricular volumes and/or function the best correlations were obtained by the method of evaluation of area-length of the right ventricle from two orthogonal projections (apical 4-cavity and subcostal with visualization of the outflow portion of the RV). The following correlations were assessed: telediastolic volume--r = 0.831, telesystolic volume--r = 0.815 stroke volume--r = 0.810 and ejection fraction (EF)--r = 0.752 (p less than 0.001 for all correlations). The tested method enables us at the same time to screen at least existing right ventricular dysfunction (sensitivity 0.68; specificity 0.82). In the presence of tricuspidal insufficiency (TI) increase in right ventricular function occurs which may mask its existing failure (dependence of EF on the mean pressure level in pulmonary artery was proved only in patients without TI--r = 0.594). We assume that information on right ventricular function is important not only in diseases affecting primarily the right heart but also in advanced stages of left-sided failure. Follow-up of the natural course of the disease and the effect of provided treatment by the non-invasive ECHO method is thus useful not only in research but also in clinical practice.

Cardiac Volume↗
PubMed1990

[Estimation of systolic pressure in the right ventricle (pulmonary artery) using Doppler and its importance in the detection of pulmonary hypertension].

Using the pulsed Doppler system with a high reparative frequency (HPRF), the authors made within 1 hour and 3 days after diagnostic right-sided catheterization 38 measurements of the trans-tricuspid pressure gradient in 31 consecutive patients. To the gradient calculated from the absolute velocity of flow through the jet of tricuspid regurgitation the authors added two different arbitrarily determined pressure values in the right atrium to obtain the systolic pressure in the right ventricle--RVSP (which assuming the absence of an obstruction between the right ventricle and pulmonary artery equals the systolic pressure in this artery). The calculated RVSP from the Doppler assessment correlated highly significantly with the directly manometrically obtained values of the same indicator (r = 0.973; p less than 0.001). An even closer correlation was obtained when using a differentiated estimate of the pressure in the right atrium/according to the filling of the jugular veins) (r = 0.977; p less than 0.001). From the RVSP values the authors tried to predict the presence of pulmonary hypertension (PH) diagnosed from the median pressure in the pulmonary artery (PAP greater than or equal to 20 mm Hg which was considered conclusive). Using the arbitrarily assessed range of systolic PH greater than 35 mm Hg, the sensitivity of the ultrasonographic estimate was 79% with a 60% specificity, while when the criterium of greater than 40 mm Hg was used, the corresponding values were 64% and 90%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Noninvasive quantification of the severity of aortic defects using the Doppler method].

Using Doppler method (HPRF and CW regime), the authors assessed the peak velocity of flow in an aortal spurt in 41 patients with aortal stenosis. For calculation of the transaortal pressure gradient they used a modified Bernoulli equation. The values of the calculated gradients were compared with those obtained by direct manometric assessment during catheterization of the heart after an interval of several hours to five days. Combination of two Doppler techniques correlated closely with direct assessment (r = 0.811; p less than 0.001). By application of the continuity equation in the best records of spectral analysis of velocity curves the authors calculated in 8 patients the area of the reduced aortal orifice which was very close to the area calculated by means of Hakki's formula from direct haemodynamic indicators (r = 0.948; p less than 0.001). In 33 patients the authors quantified by Doppler method the severity of aortal regurgitation from the ratio of forward and backward flow in the descending portion of the aortal arch (expressed as the % regurgitation fraction--RF). The RF values correlated well with the angiographic semiquantitative scale of severity of aortal insufficiency (r = 0.805; p less than 0.001), although they enabled the authors only to make a partial differentiation of haemodynamically severe regurgitations and mild or insignificant ones. The authors conclude that the Doppler approach makes it possible to evaluate sufficiently accurately the severity of aortic valve disease (in insufficiencies the authors recommend a more comprehensive approach), which when correctly applied and interpreted, can make non-invasive clinical diagnosis more accurate and thus permits also more accurate indication of surgical treatment of these patients.

Aortic Valve Insufficiency↗
PubMed1990

[Long-term fate of intraventricular thrombi after myocardial infarct].

Using two-dimensional echocardiography, the authors followed up 30 patients where in the course of treatment of acute myocardial infarction an intraventricular thrombus developed. A benign character (i. e. adjacent and immobile thrombus) was found in 21 patients, while a malignant (freely movable, floating, protruding) thrombus was recorded in 9 cases (70% as compared with 30%). All patients were followed up to the period of disappearance (regression) of the thrombus or within two years after infarction. The authors evaluated above all the ability of regression of thrombi and influencing their complication (above all systemic embolisms). In the whole group regression of thrombosis occurred in 25 patients (82%). In benign thrombi early regression--within three weeks after the development of infarction--occurred in 10 patients (33%) and late regression (more than three weeks) also in 10 patients. Analysis of the applied treatment revealed that all patients with early and nine patients with late regression of cardiac thrombosis had anticoagulation therapy till the thrombus disappeared. As to malignant thrombi, regression occurred only in five patients, always after at least three weeks. Systemic embolization (once into the cerebral arteries, twice into the arteries of the lower extremities) was recorded in three patients always with a malignant thrombus which was not affected by anticoagulant therapy. From the results of the investigation thus ensues that anticoagulation treatment during acute myocardial infarction and after it has in case of an intraventricular thrombus a favourable effect on the regression of the formed thrombus and it can reduce significantly the frequency of systemic embolisms which are the most serious complication.

Anticoagulants↗
PubMed1990

Cardiac hypertrophy in hypertension.

The time course of regression of left ventricular hypertrophy and changes in left ventricular function were followed in 52 middle-aged hypertensive patients divided into two groups: 30 treated with betablockers and 22 with methyldopa. In case of inadequate blood pressure control, diuretics and/or vasodilators were added in both groups. Blood pressure decreased significantly over a three-year follow-up period. The decrease was most pronounced during the first three months. The biggest decrease in posterior wall and interventricular septum thickness was detected by echocardiography also within the first three months. While complete regression of posterior wall hypertrophy was noted within the next three months, interventricular septum thickness decreased steadily over a period of two years. No significant change was seen in the septum in the third year of follow-up. Complete regression of hypertrophy was found in 30 (57.7%) of probands, with no change altogether observed in as few as two patients. Regression was incomplete in 20 (38.4%) obese patients with manifest hypertrophy at the start of the study. Regression of hypertrophy was not associated with left ventricular function deterioration and was observed even after vasodilator administration. There were no differences between the two groups of patients.

Blood Pressure↗
PubMed1990

Long-term effect of isosorbide dinitrate and nifedipine, singly and in association, in patients with chronic heart failure.

The effect of 2-month treatment with isosorbide dinitrate (120 mg day-1), nifedipine (2 x 20 mg day-1) and their combination has been assessed in 16 patients with mild to moderate chronic cardiac failure. Isosorbide dinitrate decreased right atrial (-23%), pulmonary wedge (-20%) and pulmonary arterial (-17%) pressures but did not significantly change either cardiac output or systemic and pulmonary vascular resistance. Nifedipine increased cardiac output (+13%) and decreased systemic and pulmonary vascular resistance (both -17%) with no change of pressures. Combined therapy with both drugs decreased ventricular filling pressures (-8% and -15%), systemic (-20%) and pulmonary (-13%) arterial pressures, increased cardiac output (+26%) and decreased both systemic (-29%) and pulmonary (-29%) vascular resistances. Changes during exercise were almost the same as at rest. The effect of both drugs was more pronounced in patients with more severely pathological haemodynamic measurements before treatment. We conclude that combined treatment with both preload- and afterload-reducing agents can preserve or even potentiate a favourable haemodynamic effect of individual drugs.

Blood Pressure↗
PubMed1990

The effect of thrombolytic therapy on the development of intraventricular thrombosis in acute myocardial infarction.

The authors studied the possibility to prevent the development of intraventricular thrombosis (IVT) following acute myocardial infarction (AMI) by application of early treatment of AMI, sought to identify the risk factors of IVT development, and were successful in reducing the potential of IVT to embolism by administration of appropriate therapy. A total of 200 patients with AMI were examined, with IVT diagnosed in 30 (15%). Results show that streptokinase treatment of AMI plays a role in preventing the development of IVT (1.0% incidence of IVT), with somewhat lesser protection conferred by heparin (with an incidence of 19%), and IVT present in 47% of cases when no thrombolytic or anticoagulation therapy had been administered. Of the risk factors making the patient susceptible to developing IVT, presence of an aneurysm, anteroseptal or apical AMI, decreased left ventricular ejection fraction and female sex were found to be statistically significant (p less than 0.05). Follow-up of IVT confirmed the risk of embolism in systemic arteries, especially in malignant IVT (p less than 0.01). In this case, anticoagulation therapy appears to be an effective therapeutic technique that must be initiated once the diagnosis has been established, and continued until 50% regression of the thrombus, or its complete disappearance.

Echocardiography↗
PubMed1989

[Preventing the development of intraventricular thrombosis in acute myocardial infarct with thrombolytic therapy].

The authors studied the possibilities of preventing intraventricular thrombosis (IVT) after acute myocardial infarction (AMI) by employing early therapeutical measures, and by checking the risk factors of IVT, and found a decrease in the IVT embolization potential through adequate therapy. They examined 200 patients with AMI, out of whom 30 [15%] were found to have IVT. According to the results obtained, the therapy of AMI by means of streptokinase had a prophylactic significance for preventing IVT [IVT occurrence - 10%]; a lesser preventive effect was provided by heparin with the 19% incidence of IVT, but the IVT occurred in 47% of patients without thrombolytic or anticoagulation therapy. The risk factors of statistical significance which led to IVT were apical aneurysm, anteroseptal and apical AMI, reduced left-ventricular ejection fraction and the female sex (p less than 0.05). A further IVT follow-up confirmed the risk of systemic artery embolization, especially in malignant IVT (p less than 0.01). In such cases, effective prevention seems to require anticoagulation therapy which must follow immediately after IVT diagnosis and continue up to 50% regression of the thrombus or to its total disappearance.

Female↗
PubMed1989

[The relation of flow velocity in the carotid vessels to age].

Using continual Doppler sonography, the authors measured the highest systolic blood flow rate in the extracranial carotid bloodstream in 3 groups of non-cardiac patients of an average age of 22, 76 and 93 years. In each group, the arteria carotis communis showed, with increasing age, a decrease in the highest systolic rate: 0.692 +/- 0.084 - 0.414 +/- 0.073 - 0.297 +/- 0.031 m/s (p less than 0.01 in all the three groups). Equally, a decrease in the highest systolic rate was found in the arteria carotis interna: 0.506 +/- 0.071 - 0.298 +/- 0.064 - 0.211 +/- 0.10 m/s (p less than 0.01 in all 3 groups). The paper shows a statistically significant decrease in the systolic blood rate in the carotid bloodstream related to aging (p less than 0.01) and discusses causes of this phenomenon.

Adolescent↗
PubMed1989

[Diastolic function of the left heart ventricle and new possibilities for its evaluation].

The authors present a brief account of contemporary findings pertaining to the physiology and pathophysiology of the diastolic phase of the cardiac cycle. The abnormal diastolic function of the left ventricle is documented best in ischaemic heart disease and hypertension with left ventricular hypertrophy. In these conditions the mechanisms of the development of impaired left ventricular diastolic function are described in more detail. These disorders are the early stage of affection of the heart muscle and do not depend on the quality of systolic function of the left ventricle. Isolated disorders of left ventricular diastolic function may be the cause of left-sided cardiac failure. The authors deal also with invasive and non-invasive methods which make examination of diastolic function possible and discuss in more detail Doppler visualization of the blood flow across the mitral valve.

Diastole↗