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Biomedical subjects

H Neuss

Publications and source records attributed to H Neuss.

At least 55 records · Page 3Linked to original sources
PubMed1977

[Heart rate and refractoriness of accessory A-V- pathways (author's transl)].

In 20 patients with WPW-syndrome, the effective refractory periods of accessory A-V conduction were measured by programmed atrial stimulation during His-bundle electrography. The effects of basic heart rate on this parameter were evaluated. Three groups of patients were distinguished: A) The effective refractory periods of accessory A-V conduction were clearly longer than the effective refractory periods of the right atrium in 12 patients. In these patients, acceleration of heart rate shortened the effective refractory period of accessory A-V conduction. Refractoriness of accessory A-V conduction was a linear function of cycle length. B) Block of accessory A-V conduction occured at a rather long basic cycle length in three patients. No rate dependency of refractoriness could be evaluated. Methodical problems regarding the determination of effective refractory period of accessory A-V conduction were discussed. The significance of the parameter in question in respect to the trigger mechanism of paroxysmal supraventricular tachycardias (echozone) and the ventricular rate during atrial tachycardias were demonstrated.

Adolescent↗
PubMed1976

[Longterm therapy of angina pectoris patients with a new beta-receptor blocker (author's transl)].

The beta-receptor blocker Timolol was investigated for 28 weeks in a double blind trial and then for up to 100 weeks in an open trial in patients with angina pectoris. In both phases of the investigation. Timolol caused a quite marked regression in the frequency of attacks and in the pulse rate at rest. The evaluation of therapeutic success by doctor and patient was positive for Timolol.

Adrenergic beta-Antagonists↗
PubMed1976

[Early mobilization after myocardial infarction. Hemodynamic and metabolic studies].

In a controlled study two groups of patients with acute myocardial infarction were compared. One group consisted of 75 patients who were early mobilized; a control group of 38 patients was treated conservatively. Although the early mobilized patients showed a slightly increased stress on the hemodynamics these findings had no clinical significance: the complication rate in this group was not higher than in the conservatively treated patients. The main advantage of early mobilization however as compared to conservative treatment seems to be the prognostically and psychologically favourable effect especially with respect to rehabilitation.

Acute Disease↗
PubMed1975

[Left atrial lead and stimulation in wpw-syndrome type A (author's transl)].

Normal and accessory A-V conduction were analyzed by His bundle recordings in a 49-year-old patient with WPW-syndrome type A. An open foramen ovale permitted registration of left atrial potentials as well as left atrial pacing. The effects of the pacemaker site (left or right atrial pacing) on the electrocardiographic variability of pre-excitation were studied. The effective refractory period of the accessory A-V conduction was shown to be dependent on the site of pacing. Recordings of right and left atrial potentials during runs of supraventricular tachycardia demonstrated that V-A conduction occurred via the accessory pathway.

Action Potentials↗
PubMed1975

Effects of heart rate and atropine on 'dual AV conduction'.

In patients with evidence of dual AV conduction, a premature atrial depolarization is normally conducted via a fast conducting pathway with a long refractory period. At a critically timed coupling interval, the effective refractory period is reached and now the impulse is conducted over a pathway with a slow conduction velocity and a short effective refractory period. At this moment in the His bundle electrocardiogram, a sudden increase in the AH interval occurs which is called the 'break' phenomenon. This phenomenon was studied in 14 patients, with a history of supraventricular paroxysmal tachycardia, at the patient's own heart rate, at different paced heart rates, and after the administration of atropine. In 11 patients the 'break' phenomenon could be elicited during sinus rhythm,; in 3 when the heart rate was accelerated. The effective refractory period of the fast conducting pathway was prolonged in 9 patients, remained unchanged in 3, and was shortened in 2 when the heart rate was increased. The effective refractory period of the slow conduting pathway was reached when block occurred proximal to the His bundle. This parameter was increased in 8 patients, remained unchanged in 3, and was decreased in 1 patient with augmentation of the heart rate. This effective refractory period was not measured in 2 patients. Atropine led to a shortening of the refractory period of both pathways in 8 patients studied. Atrial echo phenomena indicating the beginning of a re-entry circuit occurred at an AH prolongation that was not always identical to that measured at the point of 'break'. Widening, as well as narrowing, of the echo zone was found, indicating that the re-entry circuit was in a state of labile equilibrium. In cases where shortening of the pathways involved in the re-entry circuit was found, structures other than nodal may exist; therefore paranodal bypass must be considered.

Adolescent↗
PubMed1975

Analysis of re-entry mechanisms in the three patients with concealed Wolff-Parkinson-White syndrome.

Three patients with recurring attacks of supraventricular tachycardia and no electrocardiographic evidence of the Wolff-Parkinson-White syndrome (WPW syndrome) were studied using intracardiac recordings and atrial stimulation. The findings are interpreted as evidence of a concealed WPW syndrome. In all patients there was antegrade block of the anomalous atrioventricular (A-V) pathway while retrograde conduction was unimpaired and allowed the initiation of the observed reciprocating tachycardias. The diagnosis was based on the assumption that the ventricular myocardium was an essential link in the re-entry circuit. The three most important findings to support this assumption are: 1) retrograde conduction time, measured by the Q-A' interval (Q in ECG to atrial echo), and the rate of tachycardia were dependent on the mode of intraventricular conduction: 2) the first Q-A' interval of the tachycardia was independent of the A-H interval (initiation of atrial impulse to first activation of the His bundle) of the initiating premature atrial depolarization (PAD); 3) there was retrograde conduction following a ventricular premature beat during tachycardia at a time when the A-V node and/or the bundle of His would be refractory.

Adolescent↗