Biomedical subjects

H Kühnert

Publications and source records attributed to H Kühnert.

32 records · Page 2Linked to original sources

PubMed1988

[Electrophysiologic findings in so-called latent cardiomyopathies].

In the framework of a diagnostic cardiac catheterization for the confirmation or exclusion of an idiopathic myocardial disease 72 patients with latent cardiomyopathy (LCM) and 51 patients without pathological haemodynamic parameters (Non-CM) were examined electrophysiologically. Intraventricular and His-Purkinje conduction defects were essentially more frequently to be proved in patients with LCM than in the non-CM group, whereas an increased ventricular vulnerability in the two groups of patients was existing in about 20% of the cases. The disturbances of rhythm anamnestically frequently mentioned by patients with LCM might above all be traced back to atrial dysrhythmias, since in about one third of the examined patients an increased atrial vulnerability could be proved. Prospective studies of the course must explain, whether the pathological electrophysiological parameters are of prognostic importance in patients with LCM.

Adult↗

PubMed1988

[Transluminal electric catheter ablation in the treatment of drug-refractory focal ventricular tachycardias].

In a 46-year-old patient with dilatative cardiomyopathy and medicamentously therapy-resistant focal ventricular tachycardias after endocardial right- and left-ventricular catheter mapping a transvasal electric ablation of the focus of tachycardia was carried out. For this purpose at the left-ventricular-septally localized origin of tachycardia two electroshocks of 100 and 200 J via the electrode catheter positioned there was given. Immediately after ablation a stable sinus rhythm was to be registered; longer persisting recidivations of tachycardia did not appear again subsequently. In the further course the patient suddenly died after transitory haemodynamic improvement, in which case a new, acutely beginning arrhythmia is to be assumed as a prefinal event.

Cardiac Catheterization↗

PubMed1987

[Differential modifiability of a usual and unusual type of atrial flutter by high frequency atrial stimulation].

By means of highly frequent transoesophageal (left-atrial) atrial stimulation 69 patients with atrial flutter of type I (negative flutter waves in the leads II, III and aVF) and 35 patients with atrial flutter type II (positive flutter waves in the corresponding leads from the extremities) were treated and the results were compared with the results of right-atrial highly frequent stimulation (15 patients with type I atrial flutter, 6 patients with type II atrial flutter). In these cases the atrial flutter of type I nearly without any exception could be influenced by transoesophageal as well as by right-atrial stimulation (transfer into sinus rhythm, atrial fibrillation or atrial flutter of type II). The rate of success of the right-atrial as well as of the transoesophageal (left-atrial) stimulation was clearly lower in the atrial flutter of type II than in the atrial flutter of type I, in which cases are to be discussed as causes the slightly higher frequency of atrial flutter in type II, a smaller reentry circle, a higher rate of mechanisms of focal tachycardia and - in one part of the patients - an origin of tachycardia in the left atrium.

Atrial Flutter↗

PubMed1987

[Effect of body position on the ability to initiate paroxysmal supraventricular reentry tachycardias and on the conduction system properties of the reentry circuit].

The obtainability as well as the maintenance and termination of paroxysmal supraventricular reentry tachycardias depend upon the interaction of the individual components of the reentry circle, in which cases the properties of the pathway are influenced by the changing preponderance of the sympathetic and parasympathetic tonus and thus also by the body position. In 29 investigations by means of highly frequent and programmed transoesophageal atrial stimulation the influence of the body position on the initiation possibility of the paroxysmal supraventricular tachycardia and on the pathway properties of the individual components of the reentry circle are analysed. The investigations were performed either in the standing position or in lying position, in 16 patients for the objectivation of anamnestically reported paroxysms of tachycardia and in 13 patients for the therapy control after medicamentous stabilisation. In 6 patients supraventricular reentry tachycardias could be initiated only in standing position, in lying position only a few echo systoles appeared. In 9 patients in whom we obtained a tachycardia both in standing position and in lying position in upright posture an in most cases clear increase of the frequency of tachycardia was found. The evocation mode of the tachycardia was partly alleviated in the standing position, but also rendered difficult in several cases. It seems to be indicated to repeat the investigation under orthostatic conditions, when an adequate anamnesis of the tachycardia is present and an initiation possibility in lying position is lacking, or when a great subjective impairment in a paroxysm of tachycardia is reported and there is a relatively low frequency of tachycardia in lying position.

Adult↗

PubMed1987

[Electrical therapeutic procedures in recurrent, drug refractory tachycardias. II. Electrical transvenous catheter ablation].

In 6 patients with medicamentously therapy-refractory tachycardias (3 times auricular flutter/auricular fibrillation with very rapid atrioventricular conduction, once focal atrial tachycardia, once paroxysmal atrioventricular reentry tachycardia, once recurrent ventricular tachycardia on the basis of an interventricular reentry) percutaneous transvenous catheter ablations of the atrioventricular conduction region (bundle of His ablation, 5 cases) and the right Tawara branch (1 case), respectively, were performed. During a follow-up period of 2-26 months (on an average 10.5 +/- 8.0 months) a permanent total block in 4 cases could be obtained (3 times AV-block III. once complete right bundle branch block). In two other patients the total AV block receded to the AV block I. and II. respectively, within 2 and 8 days, respectively; in the first case the AV node reentry tachycardias were no more to be evoked, in the second case a tolerable ventricular frequency was the result during the auricular flutter recidivations. In all patients treated by means of catheter ablation after the intervention an impressive improvement of the clinical symptomatology developed. Due to possible complication and the dependence upon the pacemaker of the patients concerned which is to be expected the indication to the ablation should be made only after the exhaustion of all medicamentous possibilities and taking into consideration other electric therapy methods.

Adult↗

PubMed1986

[Therapeutic electrical procedures in recurring, drug refractory tachycardias. I. Antitachycardiac implantable pacemaker systems].

In 9 Patients with medicamentously therapy-refractory tachycardias (twice paroxysmal AV-node-reentry tachycardia, four times paroxysmal orthrodromic reentry tachycardia in the WPW-syndrome, once paroxysmal atrial reentry tachycardia, twice recurrent ventricular tachycardia) after adequate electrophysiological testings antitachycardiac pacemakers able to activate the patients were implanted. In these cases the implantable tachyblocker TUR-RFP-01 was used in 4 cases for the highly frequent volley atrial stimulation, in 2 cases for the more highly frequent volley ventricular stimulation. In 3 patients the interruption of the tachycardia was performed by ventricular underdrive stimulation by means of putting the magnet on a conventional R-wave-inhibited ventricular pacemaker. In all cases the recurrent tachycardias could reliably be terminated by the patients themselves by activation of the antitachycardiac systems (duration of the follow-up period 3-14 months, on an average 10.7 +/- 3.4 months); only in one case in the further course a change of the stimulation parameters was necessary which were carefully tested at the beginning. On account of the danger of the acceleration of the tachycardia and of the evocation of ventricular fibrillation, respectively, should, however, be performed highly frequent ventricular stimulations for the termination of ventricular tachycardias only in readiness for defibrillation.

Aged↗

PubMed1986

[Successful treatment of ventricular tachycardia by transvenous electrical ablation of the right Tawara branch].

Recurrent episodes of ventricular tachycardia not responding to medical treatment occurred in a 56 year old man. Electrophysiological investigation showed ventricular tachycardia due to bundle branch reentry. Using a method similar to catheter ablation of the atrioventricular junction an ablation of the right bundle branch was performed by an electrical shock of 250 J. While before the ablation ventricular tachycardia occurred several times a day, and its induction by programmed ventricular stimulation was facilitated by the administration of antiarrhythmic drugs, no initiation of ventricular tachycardia was possible after ablation of the right bundle branch. Over a follow-up of 4 weeks the patient has not suffered from tachycardia and the artificial right bundle branch block persists.

Bundle of His↗

PubMed1984

[Long-term results in the treatment of atrial tachycardial arrhythmias using temporary electric stimulation procedures].

In 12 of 23 patients with atrial flutter, who were cardioversed by means of electric stimulation techniques and underwent a regular after-examination, a sinus rhythm was still existing 24 months after regularization. When these long-term results which in comparison to the late results are more favourable after electroshock cardioversion are interpreted apart from the different selection of patients must be taken into consideration that the rate of immediate success of about 50% was distinctly lower than in the DC-shock cardioversion. It is to be supposed that a stimulation therapy only in those patients leads to regularization, the atrial vulnerability and recidivity of whom is less distinct, whereas in the other cases only the transgression into an atrial fibrillation is successful.

Atrial Flutter↗

PubMed1982

[Sinus node function test--diagnostic value and methodologic limits].

By means of atrial stimulation methods for the establishment of the sinus node recovery time and for the indirect calculation of the so-called sinuatrial conduction time under certain methodical conditions disturbances of the sinus node automatism and of the sinuatrial conduction may be differentiated and moreover latent dysfunctions of the sinus node may be unmasked. Methodical problems in the recognition of the sinus node recovery time by higher-frequent atrial stimulation and the calculation of the sinuatrial conduction time by programmed atrial single or double manifold stimulation result above all on that account, since the various factors which determine the reaction of the sinus node in atrial stimulation are not to be surveyed in the individual case. Since there are no obligatory and reliable criteria for the judgment of the function of the sinus node a statement on sensitivity and specificity of the diagnostic stimulation methods is scarcely possible. With regard to a therapeutic decision aid a higher-frequent stimulation for the determination of the sinus node recovery time is of greater importance than the calculation of the sinuatrial conduction time. For the identification of a disturbed function of the sinus node the two parameters make a diagnostic contribution of approximately the same value.

Cardiac Pacing, Artificial↗

PubMed1981

[The transesophageal approach to the heart in electrotherapy of tachycardia. II. Transesophageal cardioversion by means of direct current shock].

Electric experiments of cardioversion by means of direct current shock using special oesophagus electrodes were performed in 153 cases of various tachycardiac disturbances of rhythm. Here we succeeded in the conversion to the sinus rhythm in 86% of the patients with auricular flutter, in 84% of the cases with auricular fibrillation, in 3 of 4 patients with auricular tachycardias, in 10 patients with AV-junctional tachycardias without exception and in 5 of the 6 cases of ventricular tachycardias. Thus, the rate of an immediate success approximately corresponds to the conventional extrathoracic position of the electrodes. Here the smaller expenditure of energy with the possibility of an electrocardioversion also without anaesthesia as well as the readiness to the immediate electrostimulation in the case of an asystolia after cardioversion represent the essential advantages of the transoesophageal way. Despite the smaller rate of success on account of the smaller possibilities of complication, however, primarily transoesophageal stimulation techniques should be used (with the exception in auricular fibrillation), in which cases the use special oesophagus as in their failure following cardioversions by means of direct current shock transoesophageally through the same non-invasive approach. Moreover, the analysis of the oesophageally derivable ECG-potentials may facilitate the differentiation of the preexisting tachycardia.

Adult↗

PubMed1981

[The transesophageal approach to the heart in electrotherapy of trachycardiac arrhythmias. I. Transesophageal electrostimulation procedure].

Transoesophageal electrostimulation techniques were used in 124 cases of different tachycardiac disturbances of rhythm. By means of highly frequent transoesophageal atrial stimulation we succeeded in transformating into sinus rhythm in 46% of the patients with atrial flutter, in 29% of the cases with atrial tachycardias and in 75% of the patients with av-junctional tachycardias. At least atrial fibrillation (with decrease of the ventricular frequency) could be induced in 48% in pre-existing auricular flutter, in 38% in auricular tachycardias and in 15% in av-junctional atrial (partial success of therapy). Sinus tachycardias, atrial fibrillation and ventricular tachycardias could practically not be influenced by highly frequent transoesophageal atrial stimulation. Moreover, for the first time the techniques of the doubled or coupled atrial stimulation, in 2 cases also ventricular stimulations with higher frequency were tested on transoesophageal way and were introduced into the treatment of tachycardiac disturbances of rhythm. The therapeutic results of transoesophageal electrostimulation techniques seem to be comparable entirely with those of intracardiac stimulations, in which cases the non-invasive and uncomplicated techniques are accessible also to institutions without possibilities of heart catheterization.

Adult↗

PubMed1981

[Comparison of different stimulation procedures of the calculation of so-called sinoatrial conduction time].

The results of the premature individual atrial stimulation for calculating the so-called sinuatrial conduction times (SACT) were compared with those in double-manifold atrial stimulation (n = 160), frequent atrial stimulation (n = 50) and ventricular individual and double-manifold stimulation (n = 14), respectively. Premature atrial individual stimulation and atrial double-manifold stimulation in these cases gave corresponding, closely correlating results for the SACT-calculation. In frequent atrial stimulation were calculated considerably longer as well as (more infrequently) clearly shorter conduction times. Calculation errors are on the one hand thinkable due to lacking, on the other hand due to repeated sinus node depolarisation with the possibility of overdrive suppression and overdrive excitation (sinus node depression and sinus node acceleration) since the method does not allow a control of the sinus node depolarisation performed. Also in modified calculation of the SACT with consideration of the duration of spontaneous periods after stimulation the correlation to the results of the individual stimulation was relatively loose. After ventricular stimulation (and following ventriculo-atrial stimulus conduction) essentially shorter sinuatrial conduction times could be calculated than in the atrial place of stimulation. As a rule, the poststimulatory spontaneous interval showed an abbreviation compared with the duration of periods before the stimulation, in which cases the haemodynamic relations changed due to ventricular stimulation might explain the increase of frequency.

Cardiac Pacing, Artificial↗

PubMed1978

[Radiocardiographic assessment of the effect of digoxin on heart conduction insufficiency].

On 29 patients with heart insufficiency radiocardiographical investigations in rest and under stress were carried out before and after treatment with digoxin. Here it was shown that in existing functional insufficiency the determination of the stroke volume and of the minute volume in rest after digitalisation did not result in a remarkable change, but in obstructive insufficiency an improvement of the pump function of the heart began already under conditions of rest. Only in stress also in patients with functional insufficiency a significant increase of the heart-time volume and the stroke volume after application of glycoside was proved. An exacter information about the effect of glycoside was given by the temporary volume function particularly under stress.

Cardiac Volume↗

PubMed1975

[72. Evaluation of the cardiac performance by means of radiocardiographic studies].

In 2 series of investigations could be established that there exist relations between the radiocardiographically determined stroke volume and minute volume in rest and the maximum receptivity of oxygen and that the effect of a digitalisation is to be judged according to the increase of stroke and minute volume in rest and under load. The values obtained by the use of 113m indium allow an evidence concerning the functional capacity of the heart. A clear reduction of the stroke volume correlates with a diminution of the maximum oxygen pulse established during an ergometric examination and the maximum receptivity of oxygen.

Cardiac Output↗