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G Grossmann

Publications and source records attributed to G Grossmann.

At least 19 recordsLinked to original sources
PubMed2001

[Comparison of efficacy, safety and cost-effectiveness of intravenous versus oral propafenone in paroxysmal atrial fibrillation].

The purpose of this study was to investigate the efficacy, safety and cost-effectiveness of intravenous and oral propafenone in the conversion of paroxysmal atrial fibrillation propafenone to sinus rhythm. We analysed two groups of 100 consecutive patients (pts) treated because of propafenone with duration < 48 h. The first group was treated with intravenous PFN (bolus of 70 to 140 mg) and the second group was treated with oral PFN (300 to 600 mg). These 2 groups were comparable in age, sex, evidence of CAD, hypertension, mitral valve disease, history of hyperthyroidism and the level of K+ at admittance. Conversion to sinus rhythm was achieved in 64 (64%) pts who received i.v. propafenone and in 77 (77%) who received oral propafenone (p < 0.05). We conclude that oral and intravenous propafenone is safe in the termination of propafenone. Oral route of administration appears to be superior to intravenous because of greater efficacy and cost-effectiveness.

Administration, Oral↗
PubMed2000

Experimental and theoretical 31P and 77Se nuclear magnetic shielding tensors for bis(dineopentoxyphosphorothioyl) diselenide.

An intergrown crystal of two phases of bis(dineopentoxyphosphorothioyl) diselenide 1 was investigated by goniometer 31P NMR. From the angular dependence of the chemical shift, the tensors of a triclinic and a monoclinic phase were determined. The principal values sigma11, sigma22, and sigma33, of the absolute nuclear magnetic shielding tensors for the triclinic phase are 134.1, 227.2, and 375.5 ppm and for the monoclinic phase are 132.4, 227.8, and 374.2 ppm, respectively. In both cases, the principal axis 3 of the 31P tensor is directed nearly along the P=S bond and the principal axis 2 is nearly perpendicular to the S=P-Se plane. Calculations of the 31P and 77Se nuclear magnetic shielding tensors were performed for molecules of both phases of 1 and for model compounds by the sum-over-states density functional perturbation theory IGLO method. The rms distances between calculated and experimental 31P NMR icosahedral tensor values sigma(j) (j = 1, ..., 6) amount to 17-21 ppm. The calculated and experimental orientations of the 31P principal axes show a maximum difference of 5 degrees and rms distances of 3.2 and 3.3 degrees. For the principal value sigma33 of the selenium shielding tensor the agreement between calculated and experimental values is satisfactory, but the calculated values sigma11 and sigma22 are distinctly too small. Calculations for a model compound in which the methyl groups of the neopentoxy residue are substituted by protons lead practically to the same results.

Crystallization↗
PubMed2000

Influence of the orifice inlet angle on the velocity profile across a flow convergence region by color Doppler in vitro.

The converging flow field proximal to a leaking valve is determined among other things by the orifice inlet angle formed by the leaflets. Thus, the inlet angle affects the determination of regurgitant flow rate by the flow convergence method. Based on the hypothesis of spheric isovelocity surfaces, others had postulated that a local velocity within the flow convergence should change inversely proportional to changes in the three-dimensional inlet angle. This concept would allow correction of the determination of regurgitant flow for nonplanar orifice inlet angles. We tested this concept in vitro. In a flow model, the flow convergence region proximal to different orifice plates was imaged by color Doppler: funnel-shaped, planar and tip-shaped (inverted funnels) orifice plates, with circular orifices of 2- and 7-mm diameter. Velocity profiles across the flow convergence along the flow centerline were read from the color maps. As predicted, the local velocities were inversely related to the inlet angle, but only at the 2-mm funnel orifices, this effect was inversely proportional to the three-dimensional inlet angle (i.e., in agreement with the mentioned concept). However, for any 7-mm orifice and/or inlet angle of > 180 degrees, the effect of the inlet angle was considerably less than predicted by the aforementioned concept. With increasing orifice diameter and with decreasing distance to the orifice, the effect of the orifice inlet angle was reduced. The effect of the orifice inlet angle on the flow convergence region is modulated by orifice size and the distance to the orifice. Therefore, correction of flow estimates in proportion to the three-dimensional inlet angle will lead to considerable errors in most situations of clinical relevance, namely to massive overcorrection when analyzing velocities located close to wide orifices.

Blood Flow Velocity↗
PubMed1999

Aortic regurgitant flow by color Doppler measurement of the local velocity 7 mm above the leak orifice--Part 2: Comparison with cardiac catheterization.

AIMS: An in vitro study of the flow convergence region in aortic regurgitation has shown that regurgitant flow rate can be derived from the local velocity V(7 mm) at 7 mm distance above the leak orifice. This clinical study was performed to test this method in patients. METHODS AND RESULTS: In 67 patients with aortic regurgitation, the flow convergence region was imaged by color Doppler. By analogy with the afore mentioned in vitro study, velocity profiles of the acceleration across the flow convergence region were read from the color maps. The profiles were fitted by using a multiplicative regression model. The V(7 mm) was read from the regression curve, and instantaneous regurgitant flow Q was derived from the V(7 mm) with the equation developed in vitro (Q = V(7 mm).cm2/0.28). Q showed a close association with the angiographic grade. Q-derived regurgitant stroke volume correlated significantly with invasive measurements by the angio-Fick method (r = 0.897, SEE = 19.9 ml, y = 0.88x + 5.9 ml). CONCLUSIONS: Within the color Doppler flow convergence region of aortic regurgitation, the local velocity at 7 mm distance to the leak reflects regurgitant flow rate.

Adult↗
PubMed1999

Experimental neonatal respiratory failure induced by lysophosphatidylcholine: effect of surfactant treatment.

The purpose of this study was to characterize the toxic effects of lysophosphatidylcholine (lyso-PC) on neonatal lung function. Various doses of lyso-PC (from 0 to 40 mg/kg) were administered to near-term newborn rabbits. Lung-thorax compliance during mechanical ventilation was significantly decreased by doses >/=10 mg/kg, and static lung volumes during deflation were decreased by doses >/=20 mg/kg. Using the same experimental model, we investigated the effects of modified porcine surfactant (Curosurf, 200 mg/kg). Animals exposed to lyso-PC at birth and treated simultaneously with surfactant showed a satisfactory therapeutic response, whereas those treated after 30 min failed to respond. These animals also had a much larger leak of albumin into the air spaces and an elevated minimum surface tension of the lavage fluid in a pulsating bubble surfactometer, suggesting inactivation of the exogenous surfactant. Timing of surfactant administration may thus be essential for the therapeutic effect in this experimental model of acute lung injury.

Acute Disease↗
PubMed1998

Quantification of mitral and tricuspid regurgitation by the proximal flow convergence method using two-dimensional colour Doppler and colour Doppler M-mode: influence of the mechanism of regurgitation.

In patients with mitral (n=77: organic=49, functional=28) and tricuspid regurgitation (n=55: functional=54) quantified by angiography, the temporal variation of the proximal flow convergence region throughout systole was assessed by colour Doppler M-Mode, and peak and mean radius of the proximal isovelocity surface area for 28 cm/s blood flow velocity were measured. Additionally, the peak radius derived from two-dimensional colour Doppler was obtained. About 50% of the patients with mitral and tricuspid regurgitation showed a typical temporal variation of the flow convergence region related to the mechanism of regurgitation. The different proximal isovelocity surface area radii were similarly correlated to the angiographic grade in mitral and tricuspid regurgitation (rank correlation coefficients 0.55-0.89) and they differentiated mild to moderate (grade < or =II) from severe (grade > or =III) mitral and tricuspid regurgitation with comparable accuracy (82-96%). However, moderate mitral regurgitation due to leaflet prolapse in two patients was correctly classified by the mean M-mode radius and overestimated by both peak radii. Only half of the patients showed a typical variation of the flow convergence region related to the mechanism of regurgitation. The different proximal isovelocity surface area radii were suitable to quantify mitral and tricuspid regurgitation in most patients. However, in mitral regurgitation due to leaflet prolapse the use of the mean M-mode radius may avoid overestimation.

Adult↗
PubMed1998

Heart-rate variability for discrimination of different types of neuropathy in patients with insulin-dependent diabetes mellitus.

It has been shown that patients with insulin-dependent diabetes mellitus (IDDM) may reveal abnormal alterations in heart-rate variability (HRV) due to autonomic neuropathy. This study was performed to prove whether heart-rate variability can be used to stratify diabetic patients with different types of neuropathy. 48 patients with IDDM (age 17-64 yr) underwent standard function tests to assess autonomic and peripheral neuropathy. According to the results of these tests they were divided into 4 groups: Group 1: 18 patients without autonomic or peripheral neuropathy. Group 2: 13 patients with peripheral neuropathy. Group 3: 7 patients with autonomic neuropathy. Group 4: 9 patients with autonomic and peripheral neuropathy. HRV was measured by continuous 24-hours monitoring and time domain parameters were calculated. The results were compared with sex and age-matched healthy controls according to the individual characteristics of the groups and among each subgroup. Our results showed that in Group 1 there was a significant difference of time domain parameters indicative of parasympathetic influence, i.e. rMSSD and pNN50 in comparison to the control subjects (p = 0.002, p = 0.008). These results depended on the duration of diabetes; a subgroup of patients with a duration of IDDM of less than 2 years had no significant differences of HRV values. Group 2 showed the same significant differences. Group 3 and 4 showed significant differences in all measured time domain variables (SDNN, SDANN, SDNN index, rMSSD and pNN50) in comparison to the control subjects (p < 0.04). A comparison of group 1 with group 2 offered significant differences in rMSSD and pNN50 (p = 0.004, p = 0.003). Comparing group 1 with group 3 and 4, all HRV parameters showed significant differences (p < 0.03). In conclusion, HRV is able to distinguish between patients with different types of neuropathy depending on the involvement of parasympathetic or more sympathetic influenced parameters. Furthermore, this method is able to unmask early manifestations of neurological disorders prior to their detection by neurological function tests.

Adolescent↗
PubMed1998

Anisotropy of chemical shift and J coupling for P-31 and Se-77 in trimethyl and triphenyl phosphine selenides.

The 31P and 77Se magic angle spinning (MAS) nuclear magnetic resonance (NMR) experiments for selenium-77 enriched (70%) trimethylphosphine selenide 1 and triphenylphosphine selenide 2 were carried out in order to determine the nuclear magnetic shielding tensors of both nuclei and to establish values of the phosphorus-selenium indirect spin-spin coupling anisotropy delta J. The m = +1/2 and m = -1/2 subspectra were analysed by the dipolar-splitting-ratio method of Eichele and Wasylischen. For the C(S) molecule 1, delta J was obtained to be +640 +/- 260 Hz from the 31P spectrum and +550 +/- 140 Hz from the 77Se spectrum. Density functional theory (DFT) calculations give a delta J value of about +705 Hz. The value of delta J could not be determined unambiguously by analysis of the 31P spectra for the C1 molecules 2; nevertheless, an estimation of delta J was possible. The principal axis 3 of the phosphorus shielding tensor was determined to be nearly parallel to the PSe bond in 1 and 2. For the selenium shielding of 1, the same orientation was found, whereas in 2, the principal axis 2 of the selenium shielding was found to be oriented nearly along the PSe bond. The experimentally determined phosphorus nuclear magnetic shielding tensors agree well with those calculated by the IGLO method. For those two principal values of the selenium-shielding tensors corresponding to directions nearly perpendicular to the SeP bond, the agreement between calculated and experimental values is satisfactory. For the third one, corresponding to the principal axis close to the SeP bond, the calculated deshielding contributions are distinctly too small for both compounds investigated. Trends observed for the calculated molecular orbital (MO) contributions to the shielding as well as possible reasons for the underestimation of the deshielding contributions along the SeP bond are discussed.

Anisotropy↗
PubMed1998

Comparison of the proximal flow convergence method and the jet area method for the assessment of the severity of tricuspid regurgitation.

AIMS: To compare the value of the proximal flow convergence method and the jet area method for the determination of the severity of tricuspid regurgitation. METHODS AND RESULTS: The proximal isovelocity surface area radius and the jet area/length were measured in 71 consecutive patients with angiographically graded (grade 0/I-III) tricuspid regurgitation. Rank correlation coefficients with the angiographic grade were 0.71 (P < 0.001) for the proximal isovelocity surface area radius (aliasing border of 28 cm.s-1), 0.66 (P < 0.001) for the jet area, and 0.63 (P < 0.001) for the jet length. The proximal isovelocity surface area radius was significantly correlated with the jet area/length (correlation coefficients 0.82/0.77, P < 0.001). Correct differentiation between mild to moderate (grade I-II) and severe (grade III) tricuspid regurgitation was achieved in 62 of 71 patients (87%) by means of the proximal isovelocity surface area radius, in 61 of 71 (86%) by the jet area, and in 62 of 71 (87%) by the jet length. Grade III tricuspid regurgitation was not identified in five of 21 patients (24%) by means of the proximal isovelocity surface area radius, in six of 21 (29%) by the jet area, and in seven of 21 (33%) by the jet length. CONCLUSION: The flow convergence method and the jet area method are of similar value for the determination of the severity of tricuspid regurgitation. Both methods differentiated mild to moderate from severe tricuspid regurgitation in most patients. However, underestimation of severe tricuspid regurgitation in 20-30% of the cases represents a serious limitation of both methods.

Adult↗
PubMed1998

[Not Available].

Explore the source record for details and available documents.

Germany↗
PubMed1997

Signal-averaged electrocardiogram in patients with insulin-dependent (type 1) diabetes mellitus with and without diabetic neuropathy.

The purpose of this study was to investigate the presence of ventricular late potentials derived from signal-averaged ECG in patients with IDDM with and without diabetic neuropathy. Eighty patients with IDDM but without evidence of cardiac disease and 80 age-matched healthy control subjects were investigated. The corrected QT interval was measured from the standard surface electrocardiogram. Ventricular late potentials were derived from signal-averaged electrocardiogram. Out of the 80 diabetic patients, 20 had an autonomic neuropathy, 20 had an isolated peripheral neuropathy, and 40 had no symptoms of neuropathy. The corrected QT interval was significantly prolonged in patients with an autonomic neuropathy as compared with the control group (436 +/- 23 ms(x 5) vs 384 +/- 23 ms(x 5), p < 0.001). In the other patient groups there was no significant prolongation of the corrected QT interval. Ventricular late potentials were present in 3 diabetic patients with an isolated peripheral neuropathy and in 1 control subject (NS). No diabetic patient with an autonomic neuropathy had ventricular late potentials. Our data did not indicate an increased incidence of ventricular late potentials derived from signal-averaged electrocardiogram in diabetic patients independent of a coexisting diabetic neuropathy or a prolonged corrected QT interval.

Adolescent↗
PubMed1997

Pathophysiology of neonatal lung injury induced by monoclonal antibody to surfactant protein B.

Near-term newborn rabbits were exposed via the airways to a monoclonal antibody to surfactant protein B and ventilated for 0-120 min. Control animals received nonspecific rabbit or mouse immunoglobulin G, saline, or no material via the airways. Administration of the antibody at > or = 40 mg/kg elicited an immediate, significant fall in lung-thorax compliance associated with progressive intra-alveolar edema and/or alveolar collapse and necrosis and desquamation of airway epithelium, and hyaline membranes. The vascular-to-alveolar leak of human albumin and human immunoglobulin G, injected intravenously at birth and determined in lung lavage fluid 60-120 min after instillation of the antibody, was 1.8% for the left lung, with no difference between the markers. The average leak in control animals ventilated for 120 min was < 0.3% (P < 0.05). Cytospin preparations of lung lavage fluid from animals exposed to the antibody showed significantly increased recruitment of neutrophilic granulocytes. The pathology and pathophysiology of neonatal lung injury induced by the monoclonal antibody to surfactant protein B probably reflect a combination of direct inactivation of surfactant and an inflammatory response triggered by the immune reaction.

Animals↗
PubMed1996

Influence of pulse repetition frequency and high pass filter on color Doppler maps of converging flow in vitro.

Assessment of regurgitant flow by the flow convergence method is based on reading absolute velocities from color Doppler maps. Velocity overestimation by high pass filtering above 100 Hz has been reported. An extremely low filter, however, is impracticable in patients. A ratio of pulse repetition frequency (PRF)/filter of 10/1 usually results in good quality color maps as judged visually. We studied in vitro the influence of RPF and filter on the absolute velocities within color maps of the flow convergence, keeping PRF/filter at 10/1. The color maps were also compared with computerized flow simulations. Flow across different orifice plates was scanned using two different setups for each flow condition: low velocity setup (PRF 600-2500 Hz, filter 50-300 Hz) and high (PRF 1500-6000 Hz, filter 200-600 Hz). From the color maps, velocity profile curves were read along the flow center line across the flow convergence. The high velocity setup provided artefact-free color maps at a distance d = 2-4 through 8-11 mm to the orifice, the low setup at d = 6-8 through 18 mm. Within the overlapping range (d = 6-8 through 8-11 mm), the resulting curves showed no significant differences in local velocity, with a slight trend towards higher velocities with the high velocity setup (2.2-2.9%). The simulations agreed well with color Doppler except for slightly lower values at d > 10-12 mm. Changes in PRF and filter have no significant influence on the absolute velocities displayed within color maps as long as PRF/filter is kept close to 10/1.

Blood Flow Velocity↗
PubMed1996

QRS morphologies of the surface ECG of nonsustained ventricular tachycardias during holter monitoring compared with QRS morphologies of spontaneous sustained ventricular tachycardias.

The purpose of this study was to compare electrocardiographic (ECG) morphologies of nonsustained ventricular tachycardias (VTs) during Holter monitoring with the ECG morphology of documented, sustained, monomorphic VTs during the spontaneous event of tachycardia in 14 patients (9 with coronary artery disease), in whom a sustained, spontaneous monomorphic VT had been documented in a 12-lead ECG. All patients had a 24-hour Holter ECG without antiarrhythmic medication. Channel 1 of the Holter ECG was compared with leads V1, V2, and V3, and channel 2 with leads V4, V5, and V6. The Holter ECG of 10 patients in whom the QRS complex during sinus rhythm was similar to the QRS complex in the corresponding ECG leads was accepted for analysis. In 8 of the 10 patients, nonsustained VTs were detected during Holter monitoring. In one of these eight, the ECG morphology of at least one nonsustained VT in the Holter recordings was identical with the sustained VTs. Thus, incidences and ECG morphologies of nonsustained VTs during Holter monitoring do not correlate closely with those of spontaneous sustained monomorphic VTs. Therefore, most ventricular runs during Holter monitoring may have a mechanism different from that of spontaneous sustained VTs.

Adult↗
PubMed1996

Influence of the mechanism of regurgitation on the quantification of mitral regurgitation by the proximal flow convergence method and the jet area method.

In 84 patients mitral regurgitation was quantified by angiography. The mechanism of regurgitation was determined by echocardiography (organic, n = 54, functional, n = 30). The radii of the proximal isovelocity surface areas in the flow convergence region for 28 and 41 cm.s-1 blood flow velocity and the area and length of the regurgitant jet were measured using colour flow Doppler imaging. The radii of the proximal isovelocity surface areas correlated more closely with the angiographic grade than the jet parameters irrespective of the mechanism of regurgitation. In more than 90% of the patients, grades I-II mitral regurgitation were correctly differentiated from grades III-IV by means of the radii of the proximal isovelocity surface areas. Using the jet parameters, the differentiation was correct in 50-90% of the patients depending on the mechanism of regurgitation. The jet area method particularly failed to identify grades III-IV organic mitral regurgitation due to a high prevalence of eccentric jets in these patients. It is concluded that the proximal flow convergence method was suitable for the quantification of mitral regurgitation irrespective of the mechanism of mitral regurgitation. On the other hand, the value of the jet area method depended largely on the regurgitation mechanism.

Adult↗
PubMed1996

[Color Doppler echocardiography of the flow convergence region in vitro: effect of the orifice shape on proximal velocity profile].

The flow convergence method serves to determine flow across orifices (like valve leaks) by color Doppler. Both the PISA method (proximal isovelocity surface areas) and the PVP method (proximal velocity profile) were developed in vitro at circular orifice plates. Therefore, we studied the influence of a non-circular orifice shape on the color map of the flow convergence. Steady flow across orifices of the following shapes was imaged by color Doppler: Oval (6 x 2 mm), slit (12 x 1.5 mm), three-star (diameter 100, area 30 mm2), circular twin-orifice (two circular orifices diameter 2 mm at 10 mm distance from each other) and oval twin-orifice (two ovals 6 x 2 mm at 10 mm distance). As reference we imaged circular orifices with a similar opening area. The alias method was used to locate discrete velocities within the color map, and the proximal velocity profile along the flow center line was analyzed (mean of 24 subsequent images). The local velocity was plotted (y-axis) against its distance to the orifice (x-axis) providing proximal velocity profile curves. The more the orifice shape differed from circular, the more the proximal velocity profile was shifted downward: The profile proximal to the oval was not different from the reference profile proximal to the circular orifice. The profile proximal to the slit was considerably slowed, and proximal to the three-star was even slightly slower (local velocity -12 %, -23 % and -29 % at 14, 8 and 5 mm distance to the orifice). If the circular reference orifice corresponded to total flow across the twin-orifice, the proximal velocity profile of the latter was also shifted markedly downward (-20 %, -18 % and -23 % at 14, 8 and 5 mm distance to the circular twin-orifice). However, if the reference profile corresponded to flow across only one opening of the twin-orifice, the proximal velocity profile of the latter was shifted considerably upwards (+60 %, +71 % and +50 % at 14, 8, and 5 mm distance). Deviation of the orifice shape from circular leads to lower local velocities within the flow convergence; thus neglecting this orifice shape would result in underestimation of flow by the flow convergence method. However, presence of parallel neighboring flow increases the local velocities; neglecting this effect would lead to corresponding overestimation of flow.

Blood Flow Velocity↗
PubMed1996

[Unmasking an exclusively retrograde accessory pathway by catecholamines].

A 52-year-old man with frequent episodes of narrow QRS complex tachycardias with rates of 150/min was admitted for electrophysiological evaluation and treatment. P waves could be seen in the ST-segment of the surface ECG during tachycardia. Atrial stimulation during electrophysiological testing was not able to induce tachycardia. During atrial stimulation, there was no evidence of conduction via an accessory pathway or of dual AV node conduction properties. Ventricular stimulation showed complete ventriculoatrial block. After intravenous administration of the catecholamine orciprenaline, single atrial extrastimuli induced an AV macro-reentrant tachycardia with a rate of 165/min. VA conduction showed the earliest retrograde atrial activation in the left anterolateral area. Thus, there was an accessory pathway which only conducted in ventriculoatrial direction and only during adrenergic stimulation. After successful radiofrequency catheter ablation, complete ventriculoatrial block was recorded even after repeat administration of orciprenaline during ventricular stimulation. This case confirms the need to administer catecholamines in every undiagnosed tachycardia during electrophysiological testing to reveal the mechanism of the tachycardia.

Adrenergic beta-Agonists↗