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Biomedical subjects

L Seipel

Publications and source records attributed to L Seipel.

At least 289 records · Page 16Linked to original sources
PubMed1976

The effect of atropine on calculated sinoatrial conduction time in man.

This study investigates the effect of atropine on the length of the return cycles after premature atrial stimulation in man. On the assumption that sinus node automaticity is not changed by premature depolarization of the sinus node, sinoatrial conduction time (SACT) was calculated from the differences between the length of the return cycles and the spontaneous cycle length. 11 patients were studied before and after the injection of atropine. In all cases atropine caused an increase in heart rate. In 8 patients the return cycles exhibited a typical behavior. In 6 patients without signs of sinus node dysfunction, the mean calculated SACT was 109 msec, whereas 2 patients with a sick sinus syndrome (SSS) had a mean calculated SACT of 190 and 225 msec, respectively. 3 patients with SSS demonstrated an atypical pattern of the postextrasystolic pauses. In 6 patients without sinus node dysfunction, atropine caused a reduction of calculated SACT about 35%. In 2 patients with SSS the reduction was 38 and 49% of the control value, respectively, whereas in the remaining 3 patients with SSS who had an atypical return cycle pattern, a normalization occurred after the administration of atropine. We conclude that, besides its effects on sinus node automaticity, atropine has also a marked effect on sinoatrial conduction, even in patients with the sick sinus syndrome.

Arrhythmia, Sinus↗
PubMed1976

[Antiarrhythmic effect of disopyramide in ventricular extrasystole and auricular fibrillation].

Disopyramide (B 712) was tested in 39 patients with chronic arrhythmias of different kind: 23 cases with atrial fibrillation, 16 cases with ventricular ectopic beats, two cases with supraventricular tachycardias. The effect of disopyramide was compared to a pretreatment with one or several antiarrhythmic drugs (quinidine, beta-blocking agents, verapamil, ajmalin-bitartrat, aprindine, propafenone, diphenylhydantoin) which had been discontinued either due to ineffectiveness or the occurrence of intolerable side effects. Therapeutical effectiveness was controlled by on-line arrhythmia computers in the CCU or Holter monitoring. 15 patients were treated longer than 4 weeks up to 16 months (mean 35+/-22,6 weeks). The following results were achieved: 1 atrial fibrillation, abolition or significant reduction of the rate of recurrence in 10 out of 23 patients; slight reduction or no effect in 13 patients; 2. ventricular ectopic beats: abolition or significant reduction in 6 out of 16 patients, slight reduction or no effect in the remaining 10 patients. Patients who were treated successfully received the same dosis as those without therapeutical success. In cases with atrial fibrillation, the success was dependent on the duration of this arrhythmia prior to treatment. In comparison to the pretreatment with one or several of the above-mentioned anti-arrhythmic drugs, disopyramide was as effective as the drug given before. The analysis of the Ecg revealed a slight but insignificant prolongation of the time intervals. In 22 patients reversible dosage-dependent side effects were observed which are due to the vagolytic action of the drug: dry mouth, blurred vision, urinary hesitancy, nausea, headache. These side effects occurred at daily dosages between 400 to 800 mg increasing markedly in patients on 800 mg a day. The drug had to be discontinued in 4 cases because of side effects. During long-term treatment no severe side effects were observed. Thus, disopyramide may serve as an alternative to quinidine, especially if the latter has to be stopped because of side effects.

Adolescent↗
PubMed1976

[Severe atrioventricular block in 2 cases with pre-excitation syndrome].

In two patients with WPW syndrome Type A suffering from syncopes and dizziness intermittent high degree A-V block was observed. The analysis of the surface Ecg revealed in the first case a complete A-V block within the normal conduction system at the level of the A-V node. In the second case there was a constant left bundle branch block with intermittent block in the right fascicle (intermittent trifascicular block). In both cases the preexcitation syndromes could be best explained by accessory tracts bypassing the normal nodal system left side. One-to-one conduction through the bypass occurred only at a distinct range of cycle lengths, at lower frequencies the accessory tracts were refractory and a IInd or IIIrd degree A-V block occurred. However, outside this frequency zone some P waves were conducted through the accessory tracts without changes in cycle lengths. The findings support the thesis of at least two functionally different atrioventricular pathways in patients with preexcitation syndrome.

Aged↗
PubMed1975

[Ventricular fibrillation during testing of a demand pacemaker (author's transl)].

Ventricular fibrillation was precipitated in a patient with an implanted unipolar demand pacemaker while its function was being tested by switching over to a fixed-rate output by means of a magnet. There was no evidence of either myocardial infarction, abnormal electrolyte state, or digitalis intoxication. This, probably unique, case indicates that non-synchronized stimulation, even during brief switching over of a demand pacemaker to a fixed-rate one, may endanger the patient.

Aged↗
PubMed1975

[Clinical indications for pacemaker exchange and functional studies of the explanted aggregates (author's transl)].

For the purpose of examining the clinical exchange indication 96 removed Demand-pacemakers (type Medtronic 5842, 5843, 5942, 5943) had been sujected to a functional test by the manufacturers. After a service-life from 31-45 months 71% (i.e. 42 out of 59 units) and, in the group with a service-life from 31-35 months, 66% (i.e. 33 out of 51 units) of pacemaker units removed at that time were still working regularly. The mean energy loss exceeded 70% with a simultaneous mean drop of the output voltage down to 2.5 Volts. After the 25th month of the implantation date the number of battery failure increased spasmodically. Under the suspicion diagnosis of "battery exhaustion" a prophylactic "selective" exchange operation of the pace-maker units implied does not appear justifiable to us but in cases with stable AV-Block III. Providing reliable supervision of patients with sufficient self-rhythm, the exchange may be delayed up to about the 40th month after the implantation.

Electrocardiography↗
PubMed1975

[Clinical value of His bundle electrography (author's transl)].

Methodical problems, indication and clinical implication of His bundle electrography are discussed. In 200 successive patients undergoing His bundle electrography and atrial stimulation the indication was as follows: Intraventricular conduction defects in 24%, A-V block in 21%, sick sinus syndrome in 20%, preexcitation in 17%, and complex arrhythmias in the remaining cases. In 38% of the patients did the HBE prove to be of help by providing information not available after analysis of the surface ECG. In 22% this technique contributed essentially to the management of these patients. In spite of dificiencies of our knowledge of the basic mechanisms, specific therapy, and prognosis of various arrhythmias His bundle electrography is clinically useful in selected patients. Therefore, this method has become a routinely used clinical tool.

Arrhythmias, Cardiac↗
PubMed1975

A new method for automated detection of the R-on-T phenomenon.

The detection of premature ectopic beats coinciding with the T-wave of the antecedent beat is important for patient monitoring. In the method described here, the difficulties of direct measurement of QT time are avoided by evaluating the changes of QT time according to heart rate by use of a diode function generator. An analog circuit is used for comparing the computed QT time with the coupling interval of successive beats. In case of a R-on-T-phenomenon an alarm is given. The frequency of alarms is registered on a trend recorder. The methods is based on empirical equations which all contain a constant factor. Our investigations showed that the variability of this factor during longer periods of monitoring was small enough to allow sufficient exactness of the evaluation procedure.

Adult↗
PubMed1975

[Diagnostic problems in the sinus node syndrome].

The sick sinus syndrome includes numerous arrhythmias due to various functional disorders of the sinus node, the atria and the A-V junctional tissue. These disturbances of impulse formation and conduction involve many diagnostic problems. If clinical methods as ECG monitoring are of no help, provocative tests are indicated. The best indirect test of the sinus node activity is the measurement of the sinus node recovery time after overdrive suppression. In addition, the sinu-atrial conduction time, the conduction velocity within the right atrium, the A-V node and the His-Purkinje system can be measured. In patients with the sick sinus syndrome abnormalities of conduction in the specialized cardiac tissue are common in addition to sinus node dysfunction. The results of the provocative tests are important for drug therapy or pacemaker implantation.

Arrhythmias, Cardiac↗
PubMed1975

[Atrioventricular conduction in the Lown-Ganong-Levine syndrome].

In 18 patients with LGL-syndrome His bundle electrography and atrial pacing were performed. In all cases the atrial conduction time was normal, the H-V interval within the lower limit (36 msec). The A-H interval was significantly shortened (58 msec). During rapid atrial pacing four different patterns of reaction could be distinguished: 1) A-H interval unchanged (1 case). 2) Sudden prolongation of the A-H interval at a critical rate (4 cases). 3) Continuous prolongation of the A-H time according to the driving frequency (9 cases). 4) Marked delay and block (4 cases). Verapamil had only little or no effect on the A-H interval in these patients. The results indicate, that only in a few cases with LGL-syndrome the shortened A-H time is due to a James bundle bypassing completely the A-V node.

Adolescent↗