Search PubMed⌕ Search

Biomedical subjects

W Hager

Publications and source records attributed to W Hager.

At least 37 records · Page 2Linked to original sources
PubMed1983

[Quantitative determination of ethylene glycol using head-space chromatography].

A simple, easy to do, and precise method in the determination of ethylene glycol in biological material is presented. After oxidation of ethylene glycol with sodiummetaperjodate is the resulting formaldehyde with sodium-borhydride to methanol reduced. The stoechiometric amount of resulting methanol is determined by Head-Space-Gaschromatography. The determination is made with peakheight method.

Chromatography, Gas↗
PubMed1982

[Different determination of sinoatrial conduction time in patients with and without sinus node dysfunction].

Using intracardiac recordings of electrical activity and programmed electrical right atrial stimulation of the human heart, the sinoatrial conduction time (SACT) in the method of Strauss et al. 1973 (SACTc) was calculated in 80 patients with and without disturbances of rhythm and compared to the modified measurement of the SACT in the method reported by Narula et al. in 1978 (SACTN). The number of continuous stimuli variied from 4, 8 and 16 stimuli with a frequency of 10% just above the averaged spontaneous frequency. The best correlation was found between the SACTc and the SACTN16 (r = 0.74; p less than 0.001) with a regression line of: SACTN16 = 1.04 SACTc + 28.6. Under these conditions, as opposed to SACTN4 or SACTN8, the most favourable reproducibility and relative coefficient of variation (rVk) could be observed: SACTN16: rVk = 9.5%; r = 0.91; SACTN8: rVk = 12.3%; r = 0.89; SACTN4: rVk = 24.3%; r = 0.53. Higher individual values for SACTN16 were found by continuous atrial stimulation as compared to other methods of determination indicating mainly a higher depression of sinus node automaticity due to overdrive suppression. Under parasympathicolysis (1 mg atropine) the lowest values of SACT were found for SACTN4 (45.9 +/- 20.7 ms) coming closest the "true" SACT, since under these conditions neither an increase of the refractory period nor an overdrive suppression exert an influence.

Arrhythmias, Cardiac↗
PubMed1982

[Interatrial communication through the coronary sinus].

An unusual case of an interatrial communication through a defect of the coronary sinus together with coarctation of the aorta is reported. In spite of two cardiac catheterization studies, this diagnosis was missed by two different cardiology departments, and anomalous pulmonary vein connection was suspected instead. This illustrates the preoperative diagnostic difficulties which continue during surgery, when exploration of the right atrium fails to detect the suspected atrial defect. This rare anomaly should be considered in the differential diagnosis of an atrial left-to-right shunt, when the largest "oxygen step-up" is at the level of the lower right atrium, and no evidence of an atrial septal defect or transposition of the pulmonary veins can be found.

Aortic Coarctation↗
PubMed1981

[Investigations of the etiology of bradycardial rhythm disturbances (author's transl)].

As a possible etiology of cardiac conduction disturbances the sclerosis of coronary arteries and an idiopathic fibrosis are considered. In recent time also a diabetes-typical process in the coronary artery system has been discussed. Therefore we studied the distribution of atherosclerotic risk factors in 238 patients with severe cardiac conduction disturbances. The results were: 1. The incidence of risk factors in patients with cardiac conduction disturbances is relatively high. 2. Nearly all risk factors were more frequent in patients with diabetes than in patients without this disease. 3. The average number of risk factors per patient is significantly higher in diabetic than in non diabetic patients. 4. The risk factors associated with diabetes mellitus--as hypertriglyceridaemia and hypercholesterolaemia--follow the same distribution function in diabetic patients and are therefore influenced by the diabetes in a similar fashion. Our results demonstrate that the atherosclerosis is the most probable cause of cardiac conduction disturbances. It seems unlikely that a diabetes-typical vessel disease is the primary cause of conduction disturbances in diabetic patients. Our results rather seem to demonstrate that the diabetes mellitus in general advance the process of atherosclerosis.

Adult↗
PubMed1981

[Electrophysiologic effects of dopamine on the cardiac conduction system (author's transl)].

The electrophysiologic effects of dopamine (Dop.) (3 microgram; n = 11) 6 microgram/kg/min; n = 14) were studied in 20 patients (5 females, 15 males) with and without different disturbances of rhythm utilizing His-Bundle electrography and right atrial pacing. The blood pressure increased significantly (p less than 0.01) about 10% (3 microgram Dop.) or 16% (6 microgram Dop.) respectively. Electrophysiologic parameters of the sinus node (spontaneous cycle length before and during carotid sinus pressure, max. sinus node recovery time = SKEZmax, sinoatrial conduction time = SACTc were not changed significantly. In single cases the sinus node function was improved by 3 microgram Dop., otherwise 6 microgram Dop. aggravated them partially. In 5 patients with sick-sinus syndrome the prolonged SKEZmax and SACTc were not reduced significantly. The electrophysiologic parameters of the atrium (Ah-t, effective-relative-functional refractory period) were not influenced by Dop. The AV-node conduction (AH,AH in response to right atrium stimulation, max. 1 : 1 conduction, refractory periods) was not altered by the catecholamine concentration of 6 microgram Dop. The intranodal conduction was improved by 3 microgram Dop. irrelevantly. No influence was seen in 3 patients with a delayed AV-conduction. The possible mechanism of the ineffective shortening of the AV-conduction may be the baroreceptor reflex caused by the enhanced blood pressure. The intraventricular conduction time (HV) was improved in some cases insignificantly, no differences was seen in the aberrant conduction of the His-Purkinje system provoked by paired stimulation.

Arrhythmias, Cardiac↗
PubMed1980

[Hemodynamic and electrophysiologic effects of the new calcium antagonist Ro 11-1781 (author's transl)].

In a 3-part study the new calcium-antagonist Ro 11-1781 was investigated in respect to hemodynamic, electrophysiologic and antiarrhythmic effects. In the first part of the investigation, systolic time intervals were determined as an indicator of left ventricular performance in 10 patients without cardiac disease before and 5 min after i.v. injection of Ro 11-1781 (1 mg/kg/body weight). At the same time blood pressure was measured. There was a significant decrease in systolic and diastolic blood pressure (p < 0.01). Due to the resulting activation of the sympathetic nervous system by baroreflex, heart rate increased by 7 bpm (p < 0.01), there was a shortening of the pre-ejection period PEPc by 15 ms (p < 0.01), whereas left ventricular ejection time LVETc was not changed significantly. The ratio PEPc/LVETc decreased significantly (p < 0.01), reflecting the increase of left ventricular contractility, which results from the activation of the sympathetic nervous system. The PQ interval was increased (16 ms, p less than 0.01), an atrioventricular block however was not seen. In the second part of the investigation, sinus node function was studied in 8 patients by His-bundle electrography and programmed stimulation of the right atrium. There was no significant change in sinus-node recovery time, sinu-atrial conduction time, sinus-node rate and atrial conduction time in response to Ro 11-1781. However, in 2 patients with sinus-bradyarrhythmia a second-degree sinu-atrial block was provoked by the calcium-antagonist. The drug was shown to have a negative dromotrope effect to the AV node, reflected by an increase of the PQ interval (p < 0.01), AH interval (p < 0.01) and a decrease (p < 0.01) of the maximal 1:1 conduction of the AV node, whereas the HV interval was not changed significantly. The antiarrhythmic effects of Ro 11-1781 were studied in 13 patients with atrial flutter, atrial fibrillation or paroxysmal supraventricular tachycardia: In 10 patients the injection of the calcium-antagonist produced a marked decrease in ventricular rate for a short time reflecting a neagative dromotrope effect in the AV node. In 5 patients conversion to sinus rhythm was observed.

Adult↗
PubMed1979

[Electrophysiologic effects of dobutamine on cardiac conduction system (author's transl)].

The electrophysiologic effects of dobutamine (D) (3 and/or 6microgram/kg/min), a new beta1 stimulator, was studied in 12 patients with different disturbances of rhythm (sinus-node dysfunction, AV-block, sinus-bradycardia, paroxysmal tachycardia) utilizing His-bundle electrography and right atrial pacing. During infusion of D sinus-rate (HR) increased significantly from 61 to 71/min. Not only in cases with enhanced sinus-node-recovery-time (SKEZ) both, the absolutely (p less than 0.05) and the corrected SKEZ(-18%,-26%) were reduced by D otherwise the calculated sino-atrial-conduction time (SACTc) was shortened only in single cases. No effect could be registered in intraventricular (HV) conduction time, whereas the AV-nodal conduction time (AH) was significantly (p less than 0.05) reduced, more effect was seen at increasing stimulation of heart rate. The intraatrial conduction time (Ah-t) was shortened not significantly. In connection with reduced AH-interval the maximum of conduction frequency of the AV-node was significantly enhanced (10%, 13%). D shortened the refractory-period (RP) of atrium and AV-node, the effect was significant (p less than 0.05) only in the functional-RP of the atrium and relative RP of the AV-node.

Adult↗
PubMed1978

[Alterations of systolic and electrocardiographic time intervals in normal patients by Ro 11-1781, a new calcium-antagonist (author's transl)].

Five minutes following intravenous application of calcium antagonist Ro 11-1781 (1 mg/kg BDW) PQ duration increased significantly in 10 healthy volunteers without more severe atrioventricular conduction disturbances. Both, systolic and diastolic blood pressure decreased and heart rate increased significantly. Left ventricular ejection time (LVET) and the time from the beginning of QRS to the first sound (QS1) did not change in contrast to a significant decrease of the electromechanical systolic interval (QS2) and of the total pre-ejection-period (PEP). The decrease in PEP is explained by a decrease in isovolumic contraction time (IVCT). This can be regarded in connection with a decreased PEP/LVET-ratio, an expression of better heart performance. In spite of the negative inotropic effect of the calcium antagonist Ro 11-1781, our results point to an increase in left ventricular performance and in heart rate caused by an exaggerated sympathic reaction to a fall in blood pressure.

Adult↗