Biomedical subjects
Publications and source records attributed to R M Schuilenburg.
We describe a 41-year-old man with an acute dissection of the ascending aorta with fistulation into the pulmonary artery. The diagnosis was made pre-operatively by 2-D and Doppler echocardiography. Surgery was successfully performed.
Development of an acute myocardial infarction is described in two previously healthy men of 25 and 40 years respectively, shortly after taking oral amphetamine derivatives. Coronary angiography disclosed in both men a normal coronary system without stenoses or irregularities. Ventriculography revealed in both a segmental dysfunction of the left ventricle. A relationship is postulated between use of amphetamine and occurrence of acute myocardial infarction in the absence of coronary artery disease.
A patient is described with an impending myocardial infarction due to presence of an intracoronary thrombus in an otherwise normal left anterior descending artery. This case illustrates that intracoronary and intravenous administration of streptokinase can be of value in the treatment of impending myocardial infarction.
The accuracy in diagnosing aortic regurgitation was studied in 170 consecutive cineaortograms. In 85 patients (group A) cineaortograms were undertaken with Sones or Gensini catheters, which produce a jet of contrast material directed towards the aortic valve. The other 85 patients (group B) underwent cineaortography with pigtail catheters, which may cause more equal distribution of contrast material in the aortic root. In group A, 31 of 71 patients (44%) without clinically known aortic valve disease showed angiographic grade I-III/IV aortic regurgitation. In group B only 8 of 61 patients (13%) without clinical evidence of aortic valve disease had grade I-II/IV aortic regurgitation on cineaortography. This difference is statistically significant (P less than 0.001). We conclude that catheters which produce a jet of contrast medium directed straight at the aortic valve can cause artificial trivial to moderate aortic regurgitation. Angiographic evaluation of aortic regurgitation should be performed with a catheter such as a pigtail or closed-end multiple sidehole catheter in which the contrast medium is not directed straight at the aortic valve.
Explore the source record for details and available documents.
Reported herein is the case of a patient with an almost imperforate form of Ebstein's anomaly of the tricuspid valve and a small muscular ventricular septal defect through which the left ventricle communicated with the right ventricular outflow tract. This particular anatomy facilitated the successful execution of a Fontan operation. We are of the opinion that this operation could find its place among the surgical options for Ebstein's anomaly.
Explore the source record for details and available documents.
This is a case report of a 60-year-old woman with a WPW-syndrome Type A developing persistent supraventricular tachycardia refractory to medical treatment. The re-entry mechanism was based on av-junction escape beats leading to retrograde conduction through the accessory pathway in presence of sinus node dysfunction i.e. long periods of sinus arrest probably enhanced through antiarrhythmic drug therapy and/or digitalis. With the aid of electrophysiological examinations and intraoperative epicardial mapping the accessory pathway was located in the upper lateral region of the left ventricle and interrupted by an incision in the av-groove from inside of the lfet atrium. Although an additional accessory pathway, not interrupted by surgery was suggested by the postoperative electrophysiological study, the patient remained free from tachycardia over more than 18 months, except for one episode terminated promptly by overdrive pacing from the right atrium. Postoperatively sinus bradycardia and av-junctional escape rhythm prevailed.
Several hypotheses, developed in the early years of arrhythmology, and frequently used for the explanation of many types of clinical tachyarrhythmias, are often based on experiments on unusual models, unphysiologic interventions, or, in some instances, on erroneously interpreted histologic findings. However, it can be demonstrated that several of these hypotheses are valid. Focal activity, unidirectional block, extremely slow conduction velocity, differences in conduction velocity in closely adjacent regions, reentry of the excitation wave, circulating excitation waves in small or large regions of the heart and other postulated mechanisms as, for example, entrance and exit block, local ventricular fibrillation, appear to be involved in the causative mechanisms of clinical tachyarrhythmias. A multicausal genesis of at least some of these must be considered seriously, particularly those which occur in acute or chronic coronary heart disease. A recent suggestion that the injury current might be involved in the genesis of ventricular tachyarrhythmias in acute myocardial ischemia and infarction is supported by observations on several properties of this current. Progress has been made in recent years but large gaps in our knowledge of mechanisms causing arrhythmias are still present.
Explore the source record for details and available documents.
Two cases with conduction disturbances in the His bundle are described. In each it was not possible to obtain both components, H and H', of the "split" His bundle potential at one time from a single bipolar electrode catheter with an interelectrode distance of 10 mm. Initial failure to record the proximal His component (H) let to the incorrect diagnosis of block located within the atrioventricular (A-V) node, of third degree, in patient A, and of first to second degree in patient B. However, careful withdrawal of the catheter resulted in the appearance of proximal components (H), accompanied by disappearance of the distal components (H') of the His bundle potential. Apparently the lesion in the His bundle and the recording electrodes were spatially related in such a way that the bipolar electrode could not override the lesion. In view of these findings it is advocated that in patients the A-V conduction disturbances the His bundle catheter should be withdrawn carefully, if the initial recording reveals His bundle potentials bearing a time relation to the ventricular complexes, or advanced carefully, if these His potentials are related to the atrial activations, in order to demonstrate the (co)existence of a lesion in the His bundle. Search for a proximal His potential by withdrawal of the catheter should be done, if possible, while the atrium is paced at a rate in excess of the spontaneous sinus rate since the H potential may be obscured by the atrial complex if the A-V nodal transmission time is short at the spontaneous rate, as was the case with patient A. In patient B the not yet described phenomenon of bradycardia-dependent block within the His bundle was observed.
In this presentation the use of His bundle electrography in the diagnostic localization of atrioventricular conduction defects is discussed. The recording of the His potential allows an identification of conduction disturbances at a level above, in, or below the His bundle. Atrioventricular conduction can be stressed and latent conduction abnormalities thereby unmasked by atrial stimulation tests, such as the gradual increasing of the atrial driving rate, or the application of single atrial premature beats of which the coupling interval is gradually shortened. These stimulation methods make a quantitative characterization of the impulse conduction in the different parts of the A-V conduction system possible.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.