Biomedical subjects
Publications and source records attributed to D Fleischmann.
We report the case of a patient with right aortic arch (type III) mimicking a mediastinal tumor. We discuss the radiological findings together with their embryologic correlations, and emphasize the role of spiral-CT in the acquisition of imaging data under difficult diagnostic conditions.
Ultrashort turbo spin-echo sequence (TSE) has the advantage of shorter scan times, minimizing motion artifacts, but has the disadvantage of a lower signal-to-noise ratio and suffers from different artifacts. T2-weighted ultrashort TSE (echo train 24) and TSE (echo train 11) were compared in degenerative lesions of the spine (n = 9) and ligamentous lesions associated with sprained ankle injuries (n = 5). The imaging quality of ultrashort TSE was very similar to TSE. There was no difference in diagnostic reliability with ultrashort TSE compared to TSE in the spine or ankle. With regard to contrast properties a higher signal intensity of fatty bone marrow was obtained with ultrashort TSE, with consecutive lower contrast between fluid and edema on the one hand and fatty tissue on the other.
The majority of abcesses associated with Crohn's disease require surgical treatment. Since the postoperative rate of complications is high, particular care is needed in the choice of surgical therapy for patients with Crohn's disease. The interventional radiological method of percutaneous abcess drainage provides the surgeon with an alternative technique suitable both for the curative treatment of simple abcesses and for the palliation of complicated abcesses prior to elective surgical treatment. We have retrospectively analysed the drainage protocols, operation reports, and case histories of 7 patients with intra-abdominal abcesses in Crohn's disease. The results of our study emphasise the excellent clinical value of PAD in the treatment of abcesses associated with Crohn's disease.
Pneumonias caused by Candida glabrata are extremely rare and occur almost exclusively in immunocompromised patients. We report an atypical case of Candida glabrata pneumonia in a non-immunocompromised patient and describe the imaging findings on digital radiography and computed tomography.
Case report of a 22-year old patient with most severe idiopathic bronchiolitis obliterans and organising pneumonia. We discuss the diagnostic algorithm and emphasise the role of CT.
Besides general extracardiac physical side effects, the antiarrhythmic amiodarone hydrochloride gives rise to morphologically manifest organ changes. Pneumopathy has been reported in up to 8% of the patients treated with this preparation. Radiologically and histologically, the clinical picture can resemble that of exogenous allergic alveolitis. When the course is protracted there is interstitial fibrotic degeneration of the pulmonary parenchyma with a corresponding morphological correlate in the X-ray. The extent to which the changes observed result from dose-dependent toxicity of amiodarone has not been completely elucidated even now, since pulmonary changes suggestive of an immune process can occur even at low doses. When there is reason to suspect the presence of amiodarone pneumopathy, the preparation should be discontinued. Radiological and clinical findings generally regress with cortisone treatment.
During a two-year period, ten infants died suddenly and unexpectedly with a home cardiorespiratory monitor available. We investigated the compliance with appropriate monitoring technique as well as the medical and demographic factors associated with these deaths (90% were due to sudden infant death syndrome). At least six and probably eight of these ten families were noncompliant with appropriate monitoring technique. The main comparison group consisted of 211 patients for whom care with home cardiorespiratory monitors was initiated and continued. Bronchopulmonary dysplasia and severe, apparent life-threatening events were significantly increased in the subjects, as were the following characteristics: black race; lack of private medical insurance; unmarried mother; maternal age of less than 25 years; cigarette smoking by mother during pregnancy; and low Apgar scores. These diagnostic and demographic factors may be useful in predicting the infant at highest risk for sudden and unexpected death when a home monitor is prescribed. Noncompliance with proper monitoring technique patients; methods of educating parents of infants at high risk of sudden infant death syndrome with the necessity for compliance need to be developed.
70 patients were investigated by means of the atrial extrastimulus method at three different driving rates: 80, 100 and 120/min. At each rate the effective, the relative, the total and the functional refractory periods were measured. 30 patients who showed signs of atrial vulnerability at least one of the tested rates were included in the so called vulnerability group. The remaining 40 patients, who did not fulfill the criteria for atrial vulnerability, were included in the nonvulnerability group. When the two groups were compared to each other there were significant larger P waves (p less than 0.005), shorter effective refractory periods (p less than 0.001) and longer relative refractory periods (p less than 0.001) in the vulnerability group. With increasing driving rate there was an increased tendency to repletitive firing in the vulnerability group. The phenomenon of vulnerability correlated well with the rate-induced shortening of the effective and the lengthening of the relative refractory period. The above described phenomena are compatible with the concept of re-entry as the electrophysiologic mechanism of atrial vulnerability in man.
55 patients (15 subjects in whom a special cardiac disease could be ruled out and 40 patients with paroxysmal atrial fibrillation) were investigated by means of the extrastimulus method at a driving rate of 80 min-1. In 32 of the 40 patients with paroxysmal atrial fibrillation occurred signs of atrial vulnerability. When compared with the healthy subjects and the remaining 8 patients who did not fulfil the criteria for vulnerability, there were significant shorter effective and longer relative refractory periods of the right atrium in the vulnerability group. These findings suggest that the re-entry phenomenon may be the underlying mechanism of paroxysmal atrial fibrillation in the group with atrial vulnerability.
The vulnerability of the right atrium to single electrical stimuli was investigated in 100 non-selected patients. According to the response pattern to extrasystolic stimulation of the right atrium during the relative refractory period, the patients could be divided in 3 groups: Group A: no signs of vulnerability. Group B: 1 to 5 additional atrial extrasystoles after the premature atrial stimulus. Group C: runs of atrial flutter or fibrillation for at least 8 s. The 3 groups were compared with respect to the duration of the effective and relative refractory period of the right atrium. From group A to group C the effective refractory period showed a tendency to shorten, while the relative refractory period showed a tendency to prolong. These results are interpreted as supporting a reentry as the underlying mechanism of the here described atrial vulnerability.
This report describes the case of a patient with a supraventricular tachycardia with a ventricular rate of 109/min and no visible P waves in the electrocardiogram. The recording of the monophasic action potential of the right atrium disclosed an atrial tachycardia with a rate of 218/min. There was an alternans of the phase 2 of repolarisation in the action potential. This report emphasises the fact that the phenomenon of alternans occurs in man, as in the experimental animal, at a cellular level.
40 patients were examined with the extrastimulus method at 3 different driving rates (80, 100 and 120/min). It was found that the atrial conduction velocity during the relative refractory period sometimes explains a paradoxical conduction of a premature atrial beat. The AV-node conduction is mainly determined by the correlation between the functional refractory period of the right atrium (FRPRA) and the effective retractory period of the AV-node (ERPAVN). With increasing driving rate the FRPRA shortened while ERPAVN lengthened. This explains why in this study the number of patients in which the ERPAVN could be reached progressively increased from 23 at a driving rate of 80/min to 31 and 33, respectively, at the driving rates of 100 and 120/min.
A comparative investigation of the electrophysiological properties of the sino-atrial node, the right atrium, the AV-node, and the intraventricular conduction system was performed in 37 patients. 18 patients had a sino-atrial block, 8 a persistent bradycardia and 11 a brady-tachy syndrome. There are the following conclusions: 1. The greatest dysfunction of the sino-atrial node was observed in the group of patients with sino-atrial block. This can be derived from the determination of the sinus node recovery time and from the occurrence of secondary pauses. 2. The vulnerability of the right atrium, investigated by the extra-stimulus-technique, is enhanced in the brady-tachy syndrome. Measuring the duration of the P-wave and the PA-interval does not give any information about the atrial dysfunction. 3. Patients with a sino-atrial block often have a disturbed AV-node conduction. In most patients it is latent only and easily can be detected by atrial incremental pacing. 4. A hemiblock or bundle branch block is found more often in patients with sino-atrial block and sinus bradycardia than in patients with the brady-tachy syndrome. By the registration of a His-bundle-electrogram a trifascicular block can be uncovered in half of these patients. 5. In the sick sinus syndrome, there is always the possibility of additional dysfunctions in the conduction distal to the sino-atrial node. With special regard to therapeutic measures, a complete evaluation can only be made by of both endocardial recording and stimulation methods.
Using the extrastimulus method in 100 patients, premature impulses were applied during the relative refractory period of the right atrium. Depending on the atrial response to these impulses we divided our patients in the following 3 groups: Group A: no repetitive firing (61 patients); group B: 1 to 5 additional atrial extrasystoles with a total duration of maximum 1.5 s (27 patients); group C: runs of atrial flutter or fibrilation for at least 8 s (12 patients). The statistical analysis of the following parameters: age, PA interval, absolute and corrected sinus node recovery time did not show any significant difference between the 3 groups. These results suggest that the investigated parameters are of no great importance in the genesis of the atrial vulnerability.
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Five patients with second degree intraatrial block are presented. The first three cases had a sick sinus syndrome with sinus bradycardia, broad P waves and episodes of atrial flutter or fibrillation. In these patients a Wenckebach phenomenon could bei elicited by atrial stimulation at a critical driving rate between the stimulated site and the recording electrode. In the first patient this conduction disturbance was obtained at several right atrial stimulation sites. The block could be elicited in the other two patients only in a limited area of the right atrium respectively only by left atrial pacing. In the remaining two patients an atrial tachycardia with block was observed. The intraatrial conduction disturbance was manifested as an exit block around the ectopic pacemaker. In one patient the tachycardia was induced by digitalis intoxication. In the other patient no etiologic factor of the tachycardia could be found. While the first three patients presented intraatrial conduction disturbances already in sinus rhythm, the last two cases showed after recovery from the atrial tachycardia P waves of normal duration and configuration.
A 22-year-old patient with chronic supraventricular tachycardia is presented. This tachycardia was investigated by means of His-bundle electrography with atrial and ventricular stimulation. A circus movement with antegrad conduction through the AV node and retograde conduction through an accessory pathway was found as the underlaying mechanism of the tachycardia.