Biomedical subjects

N Reifart

Publications and source records attributed to N Reifart.

At least 73 records · Page 4Linked to original sources

PubMed1986

[PLacebo-controlled double blind study of the anti-ischemic efficacy of transdermal depot nitrate].

Twelve patients with stable angina pectoris were studied in a randomized double blind cross-over placebo-controlled manner utilizing exercise testing and measurement of ST-segment depression before, 2, 6 and 24 hours after application of a transdermal system delivering 5 mg or 10 mg nitroglycerin per day. All testings were performed at a constant work load and exercise time. Significant improvement of ST-segment depression was only seen at 2 hours (5 mg: -45%, 10 mg: -55%) and 6 hours (5 mg: -16%, 10 mg: -31%) but not at 24 hours. The lack of efficacy at 24 hours appears to be due to tolerance.

Administration, Cutaneous↗

PubMed1986

[Persisting volume overload of the left ventricle following surgical correction of chronic aortic insufficiency].

After aortic valve replacement for chronic aortic regurgitation, complete normalization of the left ventricular end-diastolic volume can rarely be observed. We therefore investigated the role of continual volume overload caused by persisting concomitant mitral regurgitation. 20 patients who received an aortic valve for chronic aortic regurgitation (group 1), 5 patients after operation for aortic stenosis (group 2) and 6 patients with double valve replacement because of aortic and mitral valve lesions were included in the study 1 to 108 months after operation. All patients were examined clinically and by combined first pass/equilibrium radionuclide ventriculography. In the case of significant regurgitation (greater than 20%) 2-dimensional colour-coded Doppler-echocardiography was performed in patients of group 1 to localize the regurgitant lesion. 15 patients of group 1 had a typical systolic murmur indicating mitral regurgitation. 14 of these patients had significant scintigraphic left-sided heart regurgitation: 7 patients had regurgitant fractions between 21 and 40%; 6 patients between 41 and 60%; in 1 patient RF was 64%. Echocardiography confirmed mitral regurgitation in 9 of 11 of these cases. No significant regurgitation was observed in patients of group 2; mild regurgitation was measured in 5 of 6 patients of group 3 (26 to 31%). We conclude that in patients with chronic aortic regurgitation complete normalization of the left ventricular end-diastolic volume after valve replacement may not occur in some patients because of persisting mitral regurgitation.

Aortic Valve Insufficiency↗

PubMed1986

[Two-dimensional echocardiography in the quantification of severe mitral stenosis].

The aim of the study was to evaluate the accuracy of echocardiographic quantification of mitral valve opening area in severe mitral stenosis. 31 consecutive patients with severe mitral stenosis were studied with two-dimensional echocardiography before they had complete resection of the mitral valve. The valves were examined for calcifications by x-ray. Each specimen was tensionlessly suspended in a glass cylinder, with 10 to 15 l of warm water (37 degrees C) running through it until maximal opening of the valve. Then the valvular orifice was photographed for planimetry. Now the echocardiographic results were checked again to analyse the errors of the initial assessment. In 6 out of 31 patients the size of the valvular opening area could not be assessed echocardiographically due to poor echo quality. The mean mitral opening area of the specimens was 0.92 +/- 0.32 cm2. With 1.27 +/- 0.52 cm2, the results achieved by echocardiography reached a correlation of only r = 0.44. In 9 out of 25 patients the area was assessed precisely in terms of size and anatomy. The difference between the values calculated from the specimens and echocardiograms was below 0.5 cm2 in 19 out of 25 (76%) patients and below 1 cm2 in another 4 (16%) patients. A larger difference in two patients was due to incorrect beam direction. Otherwise, false results in 10 out of 25 patients were caused by multiple inner echoes and in 2 out of 25 patients by bright reflections due to calcifications. Although the echocardiographically assessed mitral valve opening area does not correlate with the real opening area, it is possible to distinguish in most patients between severe and mild stenosis. Furthermore the valvular opening area can be exactly determined up to 0.5 cm2 in 90 percent of patients, provided that the echo beam is correctly positioned.

Adult↗

PubMed1986

[Regional myocardial ischemia in the conscious dog under echocardiography control].

Regional myocardial dysfunction is a very sensitive and early parameter of myocardial ischemia. One minute occlusion of the left anterior descending (LAD (n = 8) and circumflex coronary artery (CCA) (n = 8) by means of hydraulic occluders was performed in 10 chronically instrumented conscious dogs. In a left ventricular cross-section diastolic and systolic area (DA, SA) and area shortening (AS) as well as regional function of 6 radial sectors were evaluated with 2D echocardiography. After occlusion of the LAD, SA increased by 33% (p less than 0.05), AS decreased by 22% (p less than 0.05) while the DA remained unchanged. In 2 of 6 radial sectors (anteroseptal) shortening decreased by 41% (p less than 0.01) and 54% (p less than 0.001) respectively. Occlusion of the circumflex coronary artery CCA caused an increase in DA (18%) and SA (33%) and a reduction of AS by 24% (p less than 0.01). Contraction of the anterior wall (sectors 2 and 3) was reduced by 61% and 57% (p less than 0.001). In the same animal 10 one minute occlusions of the LAD with 5 min intervals of reperfusion caused a reproducible depression of sector 6 (septal) from 63.2 +/- 5.4% to 16.3 +/- 3.4%. In another animal 11 one minute CCA occlusions with 5 min intervals of reperfusion reproducibly decreased the contraction of sector 3 (anterior) from 85.2 +/- 6.7% to 21.4 +/- 17.0%. 2D-E allows a reproducible estimation of regional left ventricular dysfunction during ischemia. Our model has the advantage that numerous studies can be performed in the same animal, so that the results can be compared intraindividually.

Animals↗

PubMed1985

[Transfemoral angioplasty in stenosis of the isthmus of aorta].

A 14-year-old patient with severe aortic coarctation was treated by advancing a balloon catheter across the stenosis via the right femoral artery. The 4 cm long balloon, transversal diameter 15 mm, was filled with saline containing contrast media for 10 seconds. The excess pressure in the balloon was 3.5 at. Subsequently the stenosis diameter increased from 3 to 7.3 mm. The systolic pressure gradient decreased from 75 to 35 mm Hg. After the operation the foot-pulse was palpable for the first time. The highly elevated arterial pressure in the upper extremities decreased markedly. Three months after the operation the vessel diameter was 10.2 mm and the pressure gradient only 10 mm Hg.

Adolescent↗

PubMed1985

[Pericardial effusions after heart surgery. Incidence and clinical sequelae].

The frequency and clinical outcome of pericardial effusions was investigated in 104 patients following open-heart surgery. A pre- and post-operative echocardiogram was made in all cases. Pericardial effusions were present in 26%, significantly more occurring after bypass surgery (37%) than after valve replacement (15%). In 4 out of 5 cases the effusion had no haemodynamic effect and in no instance was a repeat thoracotomy necessary. A significantly higher incidence of reduced exercise tolerance, increased heart rate, atrial fibrillation and a radiologically demonstrable increase in heart size of more than 10 mm, were indicative of the presence of pericardial effusions. In contrast, central venous pressure and blood pressure were no higher than in patients without pericardial effusion. Complication-free pericardial effusions thus occur frequently after cardiac surgery. A reliable diagnosis is only possible by means of echocardiography. It remains to be shown whether the long-term clinical progress is affected.

Adult↗

PubMed1985

Hemodynamic effects of molsidomine in patients with acute myocardial infarction.

The hemodynamic effects of molsidomine were studied in 48 patients with acute myocardial infarction and compared with hemodynamic properties in a control group of 24 patients. The most pronounced decrease in pulmonary artery diastolic pressure occurs between 30 and 60 minutes after oral administration of 8 to 12 mg (n = 16). There is no major difference in action between the oral and intravenous application of 8 to 12 mg (n = 22). Its effect lasts about 3 to 4 hours and may exceed up to 8 hours in patients with left heart failure (n = 10). The mean arterial pressure is affected only with high doses (12 mg). Cardiac output decreases slightly only in patients without left heart failure. An additional intraindividual comparison of nitroglycerin (1.6 mg sublingually) and molsidomine (12 mg intravenously) (n = 11) revealed no significant difference in hemodynamic effectiveness. Molsidomine, like nitroglycerin, acts primarily to reduce cardiac preload. An additional moderate action on afterload with a slight decline in arterial pressure may be noticed at high doses.

Blood Pressure↗

PubMed1985

[Comparison of densitometric and morphometric measurements of global and regional functions using a fully digital subtraction unit].

The value of digital subtraction angiocardiography for evaluating left ventricular movement by a morphometric and densitometric technique was examined by animal experiments (dog). Reversible reduction of global and regional left ventricular function can be quantified by both methods equally well. For judging regional ejection fraction, sector display is more easily comprehended than an ejection-fraction map. For the estimation of global cardiac ejection fraction in 49 patients, morphometric diagnosis was clearly superior to cine cardio-angiography (rmorp. = 0.91; rdens = 0.65). For recognising and quantifying regional abnormalities of cardiac movement, semi-quantitative visual gradation is superior to densitometric measurements.

Absorptiometry, Photon↗

PubMed1985

[Percutaneous pulmonary valvuloplasty].

Five patients (aged between 11 and 59 years) with valvular pulmonary artery stenosis and pressure gradients between 60 and 143 mm Hg underwent percutaneous transluminal balloon valvuloplasty. Selection of the appropriate balloon size was based on the measurement of the dimension of the value anulus as a determinant from the angiogram. Balloon catheters were used with a diameter of 18 to 20 mm. After placement in the stenotic valve the balloon was filled with diluted contrast material for 10-20 s. The balloon indention by the stenotic valve disappeared suddenly during expansion with one to three atmospheres. The pressure gradient in individual patients decreased from 60 to 25, from 143 to 60, 100 to 55, 143 to 60, and 60 to 37 mm Hg, in the mean from 101 to 52 mm Hg. All patients were discharged two to four days after the procedure. During follow-up with recatheterization after three to nine months (four patients) the gradients decreased as compared to the value immediately after valvuloplasty. The exercise capacity increased in all patients. No complications were observed. Balloon valvuloplasty of pulmonary valvular stenosis seems to be an alternative to the operative procedure.

Adolescent↗

PubMed1985

[Lack of symptomatic and long-term hemodynamic effects of prazosin in chronic heart failure. Double-blind, randomized study over one year].

Long-term treatment of congestive heart failure with prazosin is disputed. Only few controlled trials have been reported so far. Our study is the first randomized double-blind placebo controlled trial over several months that also takes haemodynamic measurements into account. 25 patients with congestive heart failure classes III and IV (NYHA) received either prazosin 20 mg/d orally (n = 12) or placebo (n = 13) and were followed up closely. Before treatment, after 6 and after 12 months we performed echocardiography, heart volume (estimated by chest X-ray) and right heart catheterization at rest and during exercise. No significant differences could be noticed during follow-up concerning the following parameters: symptoms (NYHA), left ventricular end-diastolic diameter, shortening fraction, heart volume and systemic vascular resistance. While diuretics could be reduced in 3 patients with placebo an increasing dose was necessary in 6 out of 12 patients of the prazosin group. Long-term treatment of congestive heart failure with prazosin may be valuable only in exceptional cases.

Adult↗

PubMed1985

[In vitro study of transvenous commissurotomy in severe mitral valve stenoses using the balloon catheter].

To answer the question whether mitral commissurotomy with a balloon catheter is possible, the following in vitro study was performed. In 12 patients who were operated due to severe mitral stenosis the fibrotic (n = 8) or calcified (n = 4) valves were excised and mounted in a glass cylinder. In a first step a valvuloplasty was performed with a balloon catheter (size 20 mm). Mitral valve area increased by about 40%. With simultaneous inflation of a second balloon catheter (size 15 mm) valve area increased more than 100% and reached 1.63 cm2 in the mean. Valvuloplasty was successful (increase of at least 0.5 cm2) in 11/12 cases. In 9 valves the rupture occurred within the commissures, twice within the leaflets and once the opening area increased due to dilatation. Commissurotomy with a balloon catheter seems to be possible even in calcified mitral valves although in most cases a mild to moderate stenosis will remain.

Adult↗

PubMed1984

[Aortocoronary bypass operation in considerably reduced left-ventricular function caused by chronic ischemia].

Among a group of 18 patients with severe angina and an ejection fraction of less than 46%, cine-angiography was performed on 18, 2-D echocardiography on 18, radionuclide ventriculography on 13 and 201Thallium myocardial scintigraphy on 13 at rest, both pre-operatively and six months after an aortocoronary bypass operation. In nine patients there was a significant increase postoperatively in the ejection fraction (P less than 0.001) (group I), while it remained practically unchanged in the remainder (group II). Similar results were obtained with radionuclide ventriculography and echocardiography. Ischaemia at rest was demonstrated by myocardial scintigraphy preoperatively in an average of 10 out of 27 sectors in group I patients, but within six months postoperatively decreased to 3.1 (P less than 0.01). In group II patients the mean number of sectors with ischaemia at rest was pre-operatively 2.5, postoperatively 6.0. With one exception there was an improvement in left-ventricular function at rest in all patients with pre-operatively 7 or more sectors showing ischaemia at rest. These results suggest that myocardial scintigraphy makes it possible to identify those patients with severe ischaemic myocardial damage who would profit from revascularization.

Angina Pectoris↗

PubMed1984

[Percutaneous bursting of the pulmonary valve].

In a 25-year-old female patient with pulmonary valve stenosis valvuloplasty could be successfully performed using a balloon catheter inserted via the femoral vein. Balloon measurements were 2 cm width and 3 cm length, the required pressure was 5 atm. There was a decrease of the pressure gradient form 60 to 25 mm Hg, systolic right ventricular pressure decreased from 88 to 50 mm Hg. Besides transluminal angioplasty of coronary stenoses and non-surgical occlusion of patent ductus arteriosus thus a further catheter technique for treatment of organic heart disease has become available, being able to replace surgery.

Adult↗

PubMed1984

[Determination of global and regional ventricular ejection fraction by a fully digitalized technic. Results of digital subtraction angiocardiography following peripheral venous contrast injection compared to cineventriculography, 2-dimensional echocardiography and radionuclide ventriculography].

Subtraction angiocardiography (DSAK) with a fully digitalised system (DR 960) provides a well defined demonstration of the left ventricle after peripheral venous contrast injection. Cardiac volume and ejection fractions were calculated by a dedicated software programme and the findings correlated with cine ventriculography (CA) (r = 0.91), biplane echo cardiography (2 DE) (r = 0.77) and radionucleid ventriculography (RNV) (r = 0.85); the method can be used even with reduced cardiac output (EF less than or equal to 15%). Densitometric measurements of the EF on phantoms correspond with morphometric findings, but its clinical application is at present not possible because of the frequent appearance of artefacts. Analysis of regional disturbances of ventricular wall movements shows very good correlation between DSAK and CA and these appear more accurate than 2 DE. DSAK is a valuable, rapid and reproducible method with few side effects for cardiological diagnosis.

Adolescent↗

PubMed1984

Loss of effectiveness of dihydralazine in the long-term treatment of chronic heart failure.

The sustained effectiveness of the arteriolar vasodilator dihydralazine has not yet been established. Acute and long-term supplementary therapy with dihydralazine was therefore compared with placebo in 14 patients with severe congestive heart failure (classes III and IV) due to congestive cardiomyopathy. The heart failure had in most cases been refractory to treatment with digitalis and diuretics. Right and left ventricular filling pressures, cardiac output and systemic vascular resistance at rest and during exercise were measured by means of repeated right-heart catheterization. Left ventricular dimensions and contractility were measured with echocardiography, and heart volume determined by chest X-ray. Following the acute administration of 25 mg i.v. (n = 10) or 100 mg oral dihydralazine (n = 8), cardiac output increased significantly from 4.0 to 6.7 l min-1 and from 4.7 to 7.7 l min-1 respectively (2P less than 0.001). Systemic vascular resistance (SVR) decreased by about 50% (2P less than 0.02). The pulmonary artery diastolic pressure remained unchanged. At the same time, heart rate rose moderately, but significantly, and the arterial blood pressure fell slightly (approx. 7 mmHg). Shortening fraction increased from 12.5% to 17.0% (i.v.; 2P less than 0.01). During exercise, cardiac output reached about 11.7 l min-1 (i.v. and orally) as compared with 7.7 l min-1 before the administration of the vasodilator (2P less than 0.05). After a 12-week treatment period with 20 mg day-1 oral dihydralazine (n = 9), the haemodynamic effects were clearly diminished. In comparison with a placebo-period (4 weeks) following the study, only a moderate increase in cardiac output accompanied by a moderate decrease in SVR was found. In only 3 cases did the patients condition improve by one class (NYHA). All 3 had shown an initially extremely high SVR which could be effectively and persistently reduced under long-term therapy. Six patients remained unchanged, and 2 patients (class IV) worsened clinically, so that the medication had to be discontinued. Heart volume (chest X-ray) increased slightly during the 3 months of long-term therapy and notably during the one-month placebo period. According to these results, although patients with severe heart failure may show impressive haemodynamic improvement upon acute administration of dihydralazine, in most cases this improvement cannot be maintained under long-term therapy.

Adult↗

PubMed1984

[Reversibility of akinetic segments in coronary heart disease].

Akinetic wall segments not exhibiting contractions following nitroglycerin administration or in a post-extrasystolic beat are usually considered to consist of scar tissue; i.e. even by re-established or improved blood supply following aorto-coronary bypass surgery no functional improvement is expected. In the present study, the pre- and postoperative ventriculograms (RAO projection) of 24 patients undergoing bypass surgery were analyzed. Ventriculography was routinely performed following sublingual nitroglycerin and a post-extrasystolic contraction. In each patient the akinetic segment had received a bypass graft which was found to be patent on reangiography. In 7 of 24 patients (29%) the formerly akinetic segment exhibited improved contraction postoperatively; in 17 patients the segment remained akinetic. Global ejection fraction rose in the group of patients with improved akinesia from 47 +/- 10 to 65 +/- 10% (p less than 0.05). In the patients with unchanged contraction pattern, ejection fraction was found to be 56 +/- 12% prior to surgery and 54 +/- 16% after surgery (n.s.). The increase in ejection fraction was more pronounced in those patients showing improvement of anterior wall akinesia (from 39 to 72%) than it was in patients exhibiting improved inferior wall akinesis (from 54 to 59%). According to these findings, the regional ejection fraction was found to be higher postoperatively in patients with former anterior wall akinesis (78%) than in those showing inferior wall contraction abnormalities (49%). End-diastolic and end-systolic left ventricular volume changes postoperatively did not reach statistical significance, although end-systolic volume showed a clear trend to decrease (preoperative: 114 +/- 54 ml/1.73 m2; postoperative: 79 +/- 29 ml/1.73 m2; n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗

PubMed1984

Detection of atrial and ventricular septum defects by transoesophageal two-dimensional echocardiography with a mechanical sectorscanner.

Two-dimensional (transthoracic) echocardiography (2DE) and two-dimensional endoscopic (transoesophageal) echocardiography ( 2DEE ) were performed in 19 consecutive patients with atrial septum defect (ASD), and in 17 controls, 3 with ventricular septum defect (VSD) and 14 with various diseases. In detection of ASD the sensitivity was 61% (11/18) and the specificity 88% (2/17) with 2DE whereas 2DEE revealed a sensitivity of 95% (18/19) and a specificity of 100% (0/17). 2DEE enabled to visualize the VSD in all 3 patients (2DE in 1/3). With 2DEE the site and size of the atrial septum defects could be estimated well as confirmed in 14 patients who underwent cardiac surgery. The lateral resolution of the 7.5 MHz transoesophageal probe was about 0.5 cm. Further studies are required to clarify if cardiac catheterization prior to surgery of an ASD may be replaced by 2DEE .

Adult↗

PubMed1984

[Hemodynamic and echocardiographic long-term results of closed mitral commissurotomy].

During recent years open mitral commissurotomy (OMC) has seemed to be more favorable than closed commissurotomy (CMC). Up to now only few long-term results including hemodynamic data of mitral valve reconstruction have been reported. 69 of the 103 patients who underwent CMC between 1973 and 1980 were followed over a mean period of 5.3 +/- 2.1 years after intervention. 5 patients died. In 8 (11%) a prosthetic valve replacement was necessary (restenosis 4, insufficiency 2, combined valve disease 2). 36 of the patients were clinically improved (at least 1 NYHA class), 21 (30%) maintained the same NYHA class, and 7 (10%) had deteriorated. The relative heart volume (HV) from supine chest X-rays decreased from 1010 ml/1.71 m2 to 906 ml/1.73 m2 (n = 42, p less than 0.01). The mitral valve area ( MOFL ; n = 25) increased from 1.2 cm2 (Gorlin formula) to 2.6 cm2 (2D-echo) (p less than 0.001). Mean pulmonary artery pressure ( MPAP ) at rest decreased by 29% (from 33.6 mm Hg to 23.8 mm Hg, n = 37, p less than 0.001) and during exercise by 36% (from 69.5 mm Hg to 44.8 mm Hg, n = 10, p less than 0.01). The reduction in PA pressures and the increase in mitral valve area did not correlate and showed no relationship to the intraoperatively estimated success of commissurotomy. Our findings reflect very satisfactory long-term results after closed commissurotomy, which are comparable with those of open valvotomy.

Adolescent↗