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Biomedical subjects

R Jenni

Publications and source records attributed to R Jenni.

At least 235 records · Page 13Linked to original sources
PubMed1988

[Diagnostic imaging in the evaluation of heart transplant recipients].

Cardiac transplantation has become an important treatment option in terminal cardiac disease since the introduction of cyclosporin A for immunosuppression. Imaging methods play an important role in the diagnosis of all complications occurring after heart transplantation except for the transplant rejection reaction; endomyocardial biopsy is in continued use as none of the diagnostic imaging methods is able at present to diagnose rejection with sufficient accuracy. However, new imaging modalities that are only just starting to be widely used may change this in the foreseeable future.

Echocardiography↗
PubMed1987

[Doppler sonography assessment of blood flow velocity in the ascending aorta. Problems and possible solutions].

Irregularities of the transvascular distribution of blood flow within the human ascending aorta have been documented by means of 16 Doppler gates positioned along one scanline of a sector scanner. The velocity profiles recorded from ten healthy adults, ten patients suffering from hypertrophic obstructive cardiomyopathy, ten patients suffering from hypertrophic nonobstructive cardiomyopathy, and ten patients with severe aortic insufficiency exhibited nonuniformities which varied not only from individual to individual but also between the groups and depending on the phase of the cardiac cycle. These variations prevent any local measurement from being representative for the instantaneous mean velocity in all cases. A reliable mean should therefore be determined by simultaneously taking into account all velocities within the vascular cross-section. A computer simulation in order to indicate a potential solution to this problem demonstrates that an annular array transducer can be excited in such a manner that it produces a homogeneous ultrasound beam of a transverse area a hundred times larger than the one obtained in the conventional maximally focussed mode.

Aorta, Thoracic↗
PubMed1987

[Dynamics of cardiac output in patients with hypertrophic obstructive cardiomyopathy].

To characterise the duration of aortic flow velocity waveforms in hypertrophic obstructive cardiomyopathy (HOCM) the dynamics of aortic flow were investigated in 10 normals and 11 patients with hypertrophic obstructive cardiomyopathy performing 16-gated Doppler 2D-echocardiography of the ascending aorta. 16 flow velocities were recorded along the Doppler beam axis between the anterior and posterior aortic walls, and averaged over 8 beats. Flow times were derived from the flow curves and normalised by the ejection period as determined from the carotid pulse tracing. Thus, relative ejection time (% SEP) was calculated at the anterior (gate 4) and the posterior aortic wall (gate 13) as well as at the axis of the vessel (gate 9). In normals % SEP was 92 +/- 3% in gate 4, 95 +/- 4% in gate 9 and 93 +/- 3% in gate 13 (NS). In patients with HOCM % SEP was 92 +/- 5% in gate 4 and 83 +/- 4% (NS) in gate 9. At the posterior aortic wall (gate 13) % SEP amounted to 68 +/- 5% and was significantly lower than in gate 9 (P less than 0.05) and in gate 4 (P less than 0.001) respectively. It is concluded that in contrast to normals systolic flow time in hypertrophic obstructive cardiomyopathy varies along the sound beam in the ascending aorta. Flow time recorded at the posterior aortic wall is most abbreviated.

Blood Flow Velocity↗
PubMed1987

Early results after mitral valvuloplasty for pure mitral regurgitation.

In this study we present the results of 105 consecutive patients with pure mitral regurgitation who underwent surgical treatment. In all patients mitral regurgitation was associated with mitral valve prolapse: 54 patients underwent mitral valvuloplasty and 51 patients mitral valve replacement. Clinical assessment and echocardiography were used as follow-up criteria at one year after surgery. After mitral valvuloplasty, NYHA decreased from 2.7 +/- 0.8 to 1.1 +/- 0.7 (P less than 0.01) and workload capacity increased from 65 +/- 28% to 96 +/- 25% (P less than 0.001); left endsystolic atrial dimension and enddiastolic dimension decreased from 6.2 +/- 0.8 to 4.8 +/- 1.2 cm (P less than 0.001) and from 7.2 +/- 1.3 to 5.9 +/- 0.8 cm (P less than 0.01); ventricular contraction fraction did not change significantly. After mitral valve replacement, clinical and echocardiographic improvement was significant but less remarkable than after valvuloplasty; ventricular contraction fraction fell from 39 +/- 7% to 29 +/- 8% in contrast to patients undergoing mitral valvuloplasty in whom no significant change occurred. Complications were rare in both groups though only a minority of patients undergoing mitral valvuloplasty received anticoagulants. We conclude that mitral valvuloplasty in patients with pure mitral regurgitation when compared with the patients after mitral valve replacement.

Echocardiography↗
PubMed1986

Persisting myocardial sinusoids of both ventricles as an isolated anomaly: echocardiographic, angiographic, and pathologic anatomical findings.

The persistence of myocardial sinusoids in both ventricles as an isolated anomaly is described. A 21-year-old patient had progressive heart failure considered as cardiomyopathy of obscure etiology. Two-dimensional echocardiography demonstrated channel-like structures in the thickened myocardium of both hypokinetic ventricles. Angiography showed a honeycomblike inner contour in both ventricles. Autopsy proved the diagnosis of persistent sinusoids in a thickened myocardium.

Adult↗
PubMed1986

Treatment of Budd-Chiari syndrome by dorsocranial liver resection and direct hepatoatrial anastomosis.

Since 1980 an operation which reestablishes the blood outflow from occluded hepatic veins was performed in 7 patients with Budd-Chiari syndrome by one of us (A. Senning). Using extracorporeal circulation a dorsocranial cylindrical resection of the liver including the confluence of the occluded hepatic veins was performed by transcaval approach. The incised right atrium was sutured around the resected liver area. There was one intraoperative death. In 6 patients with a mean postoperative follow-up of 19.2 months (4-42 months), the patency of hepatoatrial anastomosis was documented by angiography or Doppler-2d-echocardiography. Four patients are free of symptoms and signs of Budd-Chiari syndrome. In one of two patients with associated cirrhosis compression of inferior vena cava reoccurred and in another patient esophageal varices persist. We conclude, that the hepatoatrial anastomosis is an effective treatment of Budd-Chiari syndrome.

Adult↗
PubMed1986

Echocardiographic findings late after myectomy in hypertrophic obstructive cardiomyopathy.

Postoperative echocardiograms of 50 patients undergoing myectomy for hypertrophic obstructive cardiomyopathy between 1965 and 1982 have been evaluated. In 21 patients a comparison with preoperative echocardiograms showed that postoperatively there was a significant reduction of septal and free wall thickness, an increase of left ventricular end-diastolic as well as outflow tract dimensions and a reduction or disappearance of systolic anterior motion of the mitral leaflet. Postoperative examination at intervals greater than 3 years revealed a significant increase of left ventricular and left atrial cavity size with unchanged contractile parameters and little reduction of left ventricular hypertrophy. In 4 of 12 patients evaluated greater than 8 years after myectomy, left ventricular dilatation was observed and 3 of these 4 patients developed congestive heart failure. Development of left ventricular dilatation was independent of whether a transventricular and/or transaortic approach was used for myectomy. These data indicate that the late course after myectomy in hypertrophic obstructive cardiomyopathy may be complicated by dilatation of the left ventricular cavity.

Adolescent↗
PubMed1986

Physiological profile of world-class high-altitude climbers.

The functional characteristics of six world-class high-altitude mountaineers were assessed 2-12 mo after the last high-altitude climb. Each climber on one or several occasions had reached altitudes of 8,500 m or above without supplementary O2. Static and dynamic lung volumes and right and left echocardiographic measurements were found to be within normal limits of sedentary controls (SC). Muscle fiber distribution was 70% type I, 22% type IIa, and 7% type IIb. Mean muscle fiber cross-sectional area was significantly smaller than that of SC (-15%) and of long-distance runners (LDR, -51%). The number of capillaries per unit cross-sectional area was significantly greater than that of SC (+ 40%). Total mitochondrial volume was not significantly different from that of SC, but its subsarcolemmal component was equal to that of LDR. Average maximal O2 consumption was 60 +/- 6 ml X kg-1 X min-1, which is between the values of SC and LDR. Average maximal anaerobic power was 28 +/- 2.5 W X kg-1, which is equal to that of SC and 40% lower that that of competitive high jumpers. All subjects were characterized by resting hyperventilation both in normoxia and in moderate (inspired O2 partial pressure = 77 Torr) hypoxia resulting in higher oxyhemoglobin saturation levels in hypoxia. The ventilatory response to four tidal volumes of pure O2 was similar to that of SC. It is concluded that elite high-altitude climbers do not have physiological adaptations to high altitude that justify their unique performance.

Adaptation, Physiological↗
PubMed1986

Combined two-dimensional ultrasound Doppler technique. New possibilities for the screening of renovascular and parenchymatous hypertension?

A combination of a real time phased array sector scanner and a range-gated 16-channel pulsed Doppler system was used for the evaluation of renal artery flow patterns in 25 echogenic subjects. Eight of these had renal artery stenosis, 5 an increased peripheral resistance in the kidney, and 12 showed normal renal flow patterns with consistent forward flow during the entire heart cycle. In normals, the ratio of end systolic (S2) versus early peak systolic (S1) velocity was 0.52 +/- 0.11 (range 0.37-0.84). In the patients with renal artery stenosis S2/S1 ranged from 0 to 0.30. Five of the 8 patients with renal artery stenosis could be evaluated before and after percutaneous transluminal dilatation (PTA). After successful PTA (diameter reduction less than 50% and pressure gradient less than 20 mm Hg) S2/S1 returned to normal. The patients with increased peripheral resistance due to an angiographically proven small kidney exhibited a variety of flow patterns with S2/S1 ranging from 0 to 0.29, similar to the ones with renal artery stenosis. The results suggest that the noninvasive determination of the ratio S2/S1 with the aid of ultrasound Doppler measurements permits a differentiation between normal and abnormal flow patterns and can be applied for the follow-up of patients after PTA. In utilizing the described method, neither the angle between the Doppler beam and the vessel axis, nor the vessel diameter must be evaluated.

Adolescent↗
PubMed1985

[Use of Doppler ultrasound in cardiac diagnosis].

In cardiac diagnosis Doppler ultrasound provides quantitative data in the assessment of pressure gradient and valve area in stenotic lesions. In atrioventricular valves pressure half-time can be determined. In regurgitant lesions the only method capable of providing quantitative analysis of aortic regurgitation is calculation of forward-to-reverse flow ratio by multigate Doppler. All the other single-gate Doppler or 2-D-echo Doppler methods, such as LV or LA mapping, recording of impaired mitral flow and diastolic/systolic flow ratio, permit only semiquantitative assessment of regurgitant volumes. Finally, semiquantitative analysis of shunt volumes appears possible in children.

Child↗
PubMed1985

[Is the alternating pulse a prognostically unfavorable sign for the postoperative course in patients with severe aortic defects?].

Pulsus alternans has been observed in patients with severe aortic valve disease and hypertensive or coronary artery disease, and has been considered a sign of severe ventricular dysfunction. Between 1974 and 1982 we observed 12 patients with severe aortic valve disease (10 aortic stenosis, 1 aortic insufficiency and 1 with a combination of both valve lesions) and pulsus alternans (group 1). Twelve patients (9 aortic stenosis, 1 aortic insufficiency and 2 with a combination of both valve lesions), but without pulsus alternans, served as controls (group 2). All 24 patients underwent surgery and were followed up for 36 months (group 1) and 50 months (group 2) respectively. One patient from group 2 died after surgery from cerebral hemorrhage. Mean age was similar in both groups (56 vs. 55 years). Preoperatively, the patients in group 1 were in a higher NYHA class (2.7 vs. 2.3; p less than 0.05) and had a higher heart rate (90 vs. 71 beats/min; p less than 0.005) than patients in group 2. M-mode echocardiography showed reduced left ventricular systolic shortening (23% vs. 35%; p less than 0.001) and increased left atrial diameter (4.6 cm vs. 3.8 cm; p less than 0.05) in group 1 compared with group 2. Systolic pressure gradient, aortic regurgitation, left ventricular end-diastolic and peak systolic pressure were, however, similar in both groups. Left ventricular angiographic ejection fraction was significantly reduced in group 1 (48% vs. 60%; p less than 0.01) compared with group 2. Postoperative follow-up was similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiocardiography↗
PubMed1985

[Importance of Doppler echocardiography in the assessment of heart defects].

Doppler ultrasound is now an established noninvasive method in cardiology. The most important indications are: 1. stenosis/insufficiencies of atrioventricular/semilunar valves, 2. dysfunction of artificial valves, 3. atrial and ventricular septal defects. The information obtained from Doppler ultrasound lends itself to quantitative or qualitative analysis. There is general consensus about the qualitative interpretation of Doppler ultrasound data, whereas quantitative analysis is still debated. A critical analysis of Doppler ultrasound data is a conditio sine qua non for correct interpretation.

Aortic Valve Insufficiency↗
PubMed1985

Dynamics of aortic flow in hypertrophic cardiomyopathy.

The purpose of this study was to reassess left ventricular ejection dynamics in hypertrophic cardiomyopathy, to investigate whether a premature stoppage of ejection occurs, as previously reported, and whether reliable criteria for left ventricular outflow tract obstruction can be established by non-invasive evaluation of aortic flow patterns. In a group of 21 patients with hypertrophic cardiomyopathy, composed of 9 with the obstructive form (HOCM), 9 with the non-obstructive form (HNCM) and 3 with apical hypertrophy (HACM), instantaneous flow velocities across the ascending aorta were determined non-invasively with a 16-gated Doppler 2-D echo instrument. Ten normals served as controls. The 16 flow velocities were averaged over 8 heart beats and the relative volume flow rate was calculated by microprocessor analysis. Ejection time (i.e. flow time) derived from the flow curves was compared with the available ejection period as determined from the carotid pulse tracing. In normals, ejection time amounted to 94 +/- 3% of the available ejection period, in HOCM to 92 +/- 5% and in HNCM to 93 +/- 4% (no significant differences). In HACM, however, ejection time was reduced to 71 +/- 14% of the available ejection period. In contrast to HNCM, aortic flow in HOCM was characterized by an early peak followed by a plateau at a sizably lower flow level for the rest of systole. Flow time of an abnormally short duration was the hallmark of HACM. We conclude that in patients with hypertrophic cardiomyopathy, HOCM and HNCM can be distinguished by the shape of their volume flow curves. A premature stoppage of ejection is only found in patients with HACM.

Adult↗
PubMed1985

[Acute aneurysm with prerupture of the left ventricle following inferior infarct].

A large infero-posterior aneurysm of the left ventricle following myocardial infarction is reported, which still showed the echo- and angiocardiographic criteria of a true aneurysm. Because of concomitant pericardial effusion a prerupture was suspected. A resection showed that the wall of the aneurysm was composed of epicardium and thrombi only.

Angiocardiography↗