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Biomedical subjects

K Den Dulk

Publications and source records attributed to K Den Dulk.

11 recordsLinked to original sources
PubMed1996

Cure of incessant pacemaker circus movement tachycardia by radiofrequency catheter ablation.

INTRODUCTION: Treatment of pacemaker circus movement tachycardia (PCMT) in patients with very long VA conduction times may present a problem. METHODS AND RESULTS: PCMT occurred in a 46-year-old woman with an uncommon AV nodal reentrant tachycardia who developed 2:1 AV block after fast pathway radiofrequency catheter (RF) ablation performed at another institution. Due to the long VA conduction time, PCMT could not be prevented by reprogramming the pacemaker or by the addition of antiarrhythmic drugs. Cure of the PCMT was obtained after selective RF ablation of the slow AV nodal pathway. CONCLUSION: RF ablation of the retrograde conduction offers another alternative for treatment of PCMT.

Catheter Ablation↗
PubMed1992

Demonstration of the feasibility of implantation of a skeletal muscle pulse generator for fecal incontinence in a patient with an implanted unipolar DDD pacemaker.

Electromagnetic fields and myopotentials from skeletal muscle may interfere with the function of a cardiac pacemaker. A 65-year-old woman with a unipolar DDD cardiac pacemaker underwent dynamic graciloplasty (transposition of the gracilis muscle around the anal canal and subsequent implantation of a bipolar pulse generator to stimulate the gracilis muscle), for the treatment of fecal incontinence. This gracilis pulse generator is turned "off" with an external magnet to allow defecation. Appropriate functioning of these two pulse generators (the cardiac pacemaker and the gracilis pulse generator) was tested during implantation of the gracilis pulse generator and afterwards. It was demonstrated that the combination could be used safely in this patient.

Aged↗
PubMed1990

An artificial neural network to localize atrioventricular accessory pathways in patients suffering from the Wolff-Parkinson-White syndrome.

UNLABELLED: The electrocardiographic localization of atrioventricular accessory pathways has been extensively described in the literature by a number of well-known electrophysiologists and surgeons. These descriptions, often represented as decision trees, are useful, but do not apply in all cases. To formalize the process of determining the proper localization, this expert human knowledge could be represented in an expert system. But since reasoning is partly based on the use of heuristic knowledge, and are often not represented in the written description of the human expert, the results will be suboptimal. On the other hand, by using a self-learning neural network approach, the causal relations between input (polarity of the delta waves) and output (the correct localization) do not have to be defined by the expert. It is derived by the neural network, by analyzing a learning set of cases consisting of the ECG plus the corresponding correct localization. In our set of 60 cases, 2 hours of training were required to learn how to localize all cases correctly. From a control set of 25 cases, 23 were interpreted by the system satisfactorily. CONCLUSION: the neural network approach can be useful in situations where causal relations between the electrocardiogram and underlying mechanism are partly undefined.

Artificial Intelligence↗
PubMed1989

Predictors of long-term success during closed-chest catheter ablation of the atrioventricular junction.

The predictors of long-term success during closed-chest catheter ablation of the atrioventricular junction remain unclear. Catheter ablation was performed in 32 consecutive patients, 18 male and 14 female, mean age 57 years, with intractable supraventricular tachycardia, in spite of a mean of 4.9 antiarrhythmic drugs. Duration of symptoms averaged 9.2 years, and the mean heart rate during tachycardia was 180 beats min-1. Paroxysmal atrial fibrillation or flutter was the presenting arrhythmia in 23 patients, intranodal tachycardia in four patients, and reciprocating tachycardia using an accessory pathway in five patients. There were no immediate complications, and 29 patients received a permanent transvenous pacemaker. A total of 94 shocks of 300 J (in 94% of cases) were given, (mean 2.96 shocks per patient). Chronic complete heart block was produced after one shock in nine patients (28%), and after two or more shocks (mean 3.3 +/- 1.1) in 13 patients. Modification of conduction was seen in four patients (12%). Failure to achieve any improvement of symptoms occurred in six patients (19%). There was no significant difference between the amplitude of atrial and His electrograms between patients who had complete heart block after one shock and those in whom conduction persisted. Catheter ablation was successful in 92% of patients who were given five shocks or less, but in only one of five patients (20%) who received six or more shocks. During a mean follow-up of 12 months, no patient with successful ablation during the first 24 h after catheter ablation resumed conduction or had recurrent symptomatic supraventricular tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Successful long-term catheter drainage in an immunocompromised patient with purulent pericarditis.

A case of extensive staphylococcal pericarditis following renal transplantation is described. Purulent pericarditis resolved after 18 days of continuous catheter drainage from the pericardium combined with antibiotic therapy. This case illustrates that life-threatening purulent staphylococcal pericarditis after renal transplantation in an immunocompromised patient may respond to medical therapy.

Anti-Bacterial Agents↗
PubMed1986

Importance of modes of electrical termination of ventricular tachycardia for the selection of implantable antitachycardia devices.

Different implantable systems for electrical treatment of ventricular arrhythmias are available. Information about mode of termination of ventricular tachycardia (VT) helps to select the most appropriate electrical treatment for drug-resistant VT. During 158 electrophysiologic studies, the mode of termination of 215 episodes of VT was analyzed in 2 groups of patients. Group 1 consisted of 54 patients with documented monomorphic VT and group 2 of 46 patients with other documented or suspected ventricular arrhythmias. Eighty-two patients had coronary heart disease, 8 had other structural heart disease and 10 had idiopathic VT. Termination of VT was attempted using extrastimuli and overdrive pacing; direct-current (DC) shocks were given in case of syncopal VT. During 33 of 96 studies (34%) in group 1, DC shock was required to interrupt VT, compared with 45 of 62 studies (73%) in group 2 (p less than 0.001). This difference was a result of less frequent induction of immediately syncopal VT in group 1 (14 of 129 VTs, vs 40 of 86 in group 2, p less than 0.001). Non-syncopal VT could reliably and safely be terminated by pacing in 61%, irrespective of the clinical arrhythmia. Pacing-induced acceleration of VT occurred in 6% (single extrastimuli) to 36% (over-drive pacing) (mean 26%) of attempts. Subsequent DC shock was required in half of these cases. Immediate collapse after induction of VT was not related to the presence of heart disease, but was related to a combination of VT cycle length (shorter than 260 ms) and left ventricular ejection fraction (less than 40%). Antiarrhythmic drugs reduced the need for DC shock.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Role of programmed electrical stimulation of the heart in the selection and design of implantable units for the treatment of recurrent tachycardia.

The introduction of programmed electrical stimulation of the heart opened up new ways for the diagnosis and treatment of recurrent tachycardias. Programmed stimulation not only allows study of the site of origin and mechanisms of arrhythmias, but also the evaluation of the modes of reproducible initiation and termination of tachycardia and the study of effects of drugs on the tachycardia mechanisms. By analyzing results of invasive and non-invasive programmed stimulation, the most successful pacing modality to reproducibly terminate tachycardia can be identified, but complications of pacing can also be recognized (such as the initiation of other arrhythmias). Careful consideration of the results of programmed electrical stimulation is necessary to select the best implantable unit for a particular patient, and to design or redesign new or already implanted antitachycardia units.

Arrhythmias, Cardiac↗
PubMed1984

Right and left ventricular ejection fraction in acute inferior wall infarction with or without ST segment elevation in lead V4R.

To detect right ventricular involvement, lead V4R was recorded within 10 hours of the onset of chest pain in 42 consecutive patients admitted with acute inferior wall myocardial infarction. One week after the acute infarction, multigated equilibrium radionuclide ventriculography was performed to assess right and left ventricular ejection fraction. Two weeks after the acute infarction, coronary angiography was performed to determine the site and location of the obstruction leading to the infarction. Seventeen patients had an obstruction in the right coronary artery proximal to the first branch to the right ventricular free wall (group 1); all of these had ST segment elevation in lead V4R. Fourteen patients had an obstruction in the right coronary artery distal to the first branch to the right ventricular free wall (group 2); only two of these patients had ST segment elevation in lead V4R. In 11 patients, the obstruction was located in the circumflex coronary artery (group 3); none of these had ST segment elevation in lead V4R. Nineteen patients had ST segment elevation of 1 mm or greater in lead V4R (group 4). Left ventricular ejection fraction was not different among the four groups of patients, although the right ventricular ejection fraction was significantly lower in group 1 and group 4 patients. It is concluded that ST segment elevation in lead V4R reliably identifies the group of patients with inferior wall myocardial infarction with depressed right ventricular function. This phenomenon persists for at least 1 week after infarction.

Adult↗
PubMed1984

Clinical experience with implantable devices for control of tachyarrhythmias.

Pacing is becoming an accepted form of treatment for reentry tachycardias. The different pacing modalities available and experience with a patient-activated antitachycardia pacemaker are presented in this paper. This system has bidirectional communication between pacemaker and pacemaker-activator and between pacemaker and prescription formulator (which is a sophisticated portable stimulator used for non-invasive electrophysiological evaluation of the system). This pacemaker was implanted in 18 patients with drug-resistant tachycardias. Six patients had ventricular tachycardia, 3 had A-V nodal reentrant tachycardia, 4 had the concealed accessory pathway, and 5 had the WPW syndrome. In the 3 months before implantation the mean number of admissions for termination of tachycardia was 2.1 per patient-month. During a follow-up period of 3-26 months only 6 patients were admitted once for termination of tachycardia (0.02 admissions per patient-month). The reasons for admission of these 6 patients were: defective pacemaker activator in 2 patients, inadequate control of tachycardia in 2 patients, inappropriate use of the device in 1, and inadequate intake of medication in 1. All these problems were solved easily. Eight pacemaker activators required reprogramming, which was done in 5 patients on an out-patient basis. The interval scanning mode was used in 9 patients. Nine patients required more than 2 stimuli for reproducible termination. A step-wise increase in number of stimuli was used in 5 patients. This system has proven to be a safe and effective form of treatment of drug-resistant supraventricular and ventricular tachycardias and has resulted in marked improvement of the quality of life of these patients.

Adult↗
PubMed1982

Pacemaker related tachycardias.

Three cases of pacemaker interactive tachycardia are presented. The first two are [artificial] circus movement tachycardias. In the first one the retrograde arm of the tachycardia circuit was provided by the A-V node and the antegrade arm by an atrial synchronous pulse generator. In the second case, the A-V node and, coincidentally, an A-V sequential pulse generator alternately provided the antegrade arm while the retrograde arm was by way of an accessory pathway. In the third case ventricular inhibition during A-V sequential pacing gave the paced atrial events the chance to be conducted to the ventricles with a long A-V interval. This resulted in a tachycardia with a rate of 150 bpm, instead of the programmed rate of 110 bpm.

Adult↗