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Biomedical subjects

H Neuss

Publications and source records attributed to H Neuss.

At least 37 records · Page 2Linked to original sources
PubMed1984

[Regularization of ventricular intervals in atrial fibrillation--electrophysiologic findings on the underlying mechanism].

In 13 patients with chronic atrial fibrillation, programmed right ventricular pacing was performed before and after intravenous administration of 4 mg gallopamil. Application of the Ca-antagonist resulted in a marked decrease in the ventricular response in all and in a regularization of the ventricular response (variation coefficient of the ventricular cycle length: less than 10%) in 7 of 13 cases, while atrial fibrillation persisted. During regularization right ventricular extrastimulus testing showed a constancy of the postextrasystolic interval irrespective of the changes in the coupling interval of the extrasystole. The postextrasystolic cycle was slightly longer than the basic cycle; the difference amounts to a mean value of 107 +/- 22 ms. During the control period the postextrasystolic cycle showed the same irregularity as the basic cycle. The same random distribution was observed if the first 10 cycles of the spontaneous rhythm were analyzed after a short period of ventricular overdrive pacing. After regularization the first 2-3 postpacing cycles were markedly prolonged, and during the following cycles a gradual adjustment to the length of the basic cycles before overdrive pacing was seen, resembling the warming up of a pacemaker. It is concluded that regularization is most probably due to atrioventricular nodal depression and the occurrence of a junctional escape pacemaker.

Adult↗
PubMed1983

Thrombotic complications with pacemakers.

To analyze thrombotic complications, we performed brachial phlebographies in 100 consecutive patients (group 1), about 44 months after permanent pacemakers had been installed. Thirty-nine patients showed thrombotic lesions in the veins used to pass the stimulation electrode into the right ventricle. In 10 patients the medical history and in 12 patients clinical symptoms and signs indicated an impairment of venous flow. Fifteen of the 39 patients showed complete occlusion of one venous segment; collateral vessel formation was found dependent on the site and the extent of the occlusion. In the remaining 24 patients only partial occlusion without collateralization was demonstrated. Group 2 comprised 12 patients in whom the pacing lead originally inserted via right-sided veins had been severed and the free distal end left unsecured intraluminally when the second electrode was inserted via the left-sided cephalic vein. In all these patients phlebography about 19 months later revealed thrombotic complications, while 11 presented with clinical symptoms and signs. The incidence of thrombotic complications including segmental occlusion after the application of permanent pacer leads is only one-third of patients with segmental occlusion symptoms. However, since severed leads produce severe symptomatic complications in almost all cases their removal is mandatory.

Adult↗
PubMed1983

Effects of flecainide on electrophysiological properties of accessory pathways in the Wolff-Parkinson-White syndrome.

The effect of flecainide in 12 patients with the Wolff-Parkinson-White syndrome was analyzed with respect to the anterograde and retrograde conduction properties of the accessory pathway, the modes of initiation and termination of circus movement tachycardias, and the ventricular response during induced atrial fibrillation. The principal effect of this drug was to depress both anterograde and retrograde conduction of the accessory pathway. In 8/9 cases circus movement tachycardia was terminated by prolongation of the retrograde effective refractory period of the accessory pathway. Flecainide increased the shortest and the mean cycle length during induced atrial fibrillation. It is concluded that the drug may be of potential benefit in patients with paroxysmal supraventricular tachycardias in patients with the Wolff-Parkinson-White syndrome.

Adult↗
PubMed1983

[Modification of hemodynamics in tachycardiac atrial fibrillation by metoprolol and verapamil].

Hemodynamic effects of the beta-receptor-blocking agent metoprolol (100 mg orally) and the calcium antagonist verapamil (160 mg orally) were analyzed in 24 patients with atrial fibrillation of different etiology (idiopathic atrial fibrillation, 6 cases; congestive cardiomyopathy, 6 cases; mitral stenosis, 5 cases; mitral regurgitation, 6 cases). 2 h after the administration of either metoprolol or verapamil heart rate was reduced significantly both at rest and during exercise. Cardiac output during exercise was significantly diminished under metoprolol in all groups of patients, whereas no effects were noted under verapamil. Peripheral vascular resistance was significantly decreased by verapamil both at rest and during exercise. No change in total peripheral resistance was noted after metoprolol at rest, but an increase occurred during exercise. Different effects on peripheral circulation may explain the different patterns of cardiac performance observed after heart rate reduction in atrial fibrillation by a calcium antagonist and a beta-blocking agent.

Atrial Fibrillation↗
PubMed1982

Coronary hemodynamics in simulated paroxysms of ventricular tachycardia: role of myocardial impairment and of extravascular resistance.

In 6 patients with healthy hearts (controls), 17 with coronary artery disease (CAD) and 6 with left ventricular hypertrophy due to aortic valvular disease, aortic pressure, coronary sinus blood flow (CSF) and lactate extraction were determined before and after the sudden onset of a paced ventricular tachycardia of 170 bpm (VT 170 = simulated paroxysmal ventricular tachycardia). Comparison to parameter changes during dipyridamol vasodilation revealed reduced coronary vascular reserve for CAD and hypertrophy. While VT induced a reduction of aortic pressure (stabilized by an average of 22%, and most excessively for CAD; p less than 0.05) and CSF remained at/or slightly above control levels (by an average of 31%; p greater than 0.05) equally for all groups (p greater than 0.05), lactate production in the groups with CAD and hypertrophy indicated myocardial impairment by ischemia. Excessively greater increases of CSF during dipyridamol vasodilation (vs. VT) for all groups suggested VTs extravascular resistance increase to have limited the extent of the potential of coronary vascular decrease. With one variable being kept constant (i.e. 'clamping' the vascular component of coronary resistance at its limit by dipyridamol), tachycardia during dipyridamol (D) vasodilation (VT 170+D and VT 140+D) in the controls and in the CAD group resulted in a linear decrease of CSF, allowing quantification of impaired coronary reserve for CAD. We concluded from the observations that: (1) paroxysmal VT demands fast therapeutic action foremost in the impaired myocardium, and (2) tachycardia per se acts as limiting factor for coronary blood flow via increase in extravascular resistance (aside from a shortened diastole).

Aorta↗
PubMed1982

[Heart rate reduction in atrial fibrillation with a rapid ventricular response by Gallopamil, a Ca-antagonist (author's transl)].

20 patients with atrial fibrillation and rapid ventricular response were treated with the new calcium-antagonist Gallopamil. The effects on heart rate were evaluated by Holter-monitoring. A significant decrease of heart rate with a duration of 10 hours was found in 10 patients after acute oral administration of 100 mg Gallopamil. In 5 patients a regularization of the ventricular response was observed, suggesting an AV junctional escape rhythm during AV nodal block. However, no relevant bradycardia was seen. The maximal decrease of heart rate was seen 2 to 4 hours after application. Oral administration of 3 times 50 mg Gallopamil daily decreased heart rate after a treatment period of 1 week to about 79% of its control values. This effect started 1 hour after application of the first dose in the morning and it lasted for 7 hours after the evening dose.

Administration, Oral↗
PubMed1982

[Hemodynamic consequences of suddenly abolished atrial contraction].

The effects of several modes of stimulation (right ventricular pacing during sinus rhythm, right ventricular pacing during induced atrial fibrillation, and atrioventricular (AV) sequential pacing with an AV delay of 130 msec) on blood pressure and cardiac output were investigated in 10 patients with normal left ventricular function. The stimulation rates were 110, 140, and 170/min for each stimulation mode. There were no significant differences between ventricular pacing in sinus rhythm and ventricular pacing in atrial fibrillation as regards blood pressure and cardiac output. Ventricular stimulation during atrial fibrillation resulted in a significant fall in systolic blood pressure (84%, p less than 0.05) even at a rate of 140/min, whereas in AV-sequential pacing systolic blood pressure only fell to 87% of the baseline value at a rate of 170/min. A significant decrease in cardiac output occurred at rates of 140/min ventricular pacing during atrial fibrillation and at rates of 170/min with AV-sequential pacing. The results underline the importance of active ventricular filling in tachycardia. There were no significant differences in the measured parameters when ventricular pacing with AV-dissociation was compared with ventricular pacing at identical rates during atrial fibrillation.

Atrial Fibrillation↗
PubMed1982

[Complications in the venous system in patients with transvenous implanted pacemakers].

There is a little account in the literature regarding early and late thrombotic complications in connection with permanent pacer application (PPA), although, clinically this is of relevance. Therefore, upper thoracic phlebography (UTP) was carried out 44 +/- 10 months after PPA in 100 consecutive pts with a mean age of 62 years. Sixty-one UPTs were normal, 15 UTPs showed occlusions of the axillary and/or subclavian vein and 24 presented with minor thrombotic changes. Reliable clinical diagnoses had been made in 10 pts only prior to UTP. In addition, 12 pts had UTPs 19 +/- 12 months after malfunctioning electrodes had been severed and each proximal stump left within the venous cavity on occasion of the repeated PPA. Clinical complications in these pts consisted of total occlusion of the superior caval vein in 2 and multiple pulmonic embolism (clinically and scintigraphically) in 3 pts. With the mobile part of the retained electrode above the left brachiocephalic vein inflow in 8 pts, occlusion had taken place in this very region. In addition, the free floating stump of the electrode was found in the pulmonary artery, in the right atrium and the right ventricle, in one pt each.

Adult↗
PubMed1981

[Clinidine-induced bradycardia: studies of the effect on the human sinus node (author's transl)].

Heart rate, atrioventricular conduction, sinus-node recovery time and effectiveness of carotid-sinus massage on heart rate were measured before and every five minutes after intravenous injection of 0.15 mg clonidine (Catapresan) in 11 patients (averaged age 60 years) with symptomatic bradycardia (dizzy spells, syncope, palpitations). Th results indicated the following significant (P less than 0.05) mean maximal effects: heart rate fell by 12% (from 59 to 52/min), capacity of atrioventricular conduction by 9% (from 132 to 121/min), while maximal sinus-node recovery time ("over-drive suppression") doubled (from 1704 to 3562 ms), heart rates of 120, 150 and 200/min being used for diagnostic atrial overdrive stimulation at each five-minute period after clonidine. During clonidine administration three patients developed a so-called hypersensitive carotid sinus reflex, in two patients the effectiveness of carotid sinus massage decreased, in three if increased, while in three it remained normal. It is concluded that (1) during bradycardia, initiated or increased by sympatholytic drugs, tests should be undertaken to exclude latent sinus-node syndrome and (or) hypertensive carotid-sinus reflex; (2) clonidine should not be used in patients with signs of sinus-node dysfunction.

Aged↗
PubMed1981

Effects of clonidine on sinus node function in man.

Drugs interfering with sympathetic tone may result in depression of the function of the sinus node, especially in patients with disease of the sinus node. In 11 patients presenting with palpitations, vertigo, or syncope, the heart rate, the recovery time of the sinus node, the carotid sinus pressure slowing, and the atrioventricular conduction capacity were assessed before and every five minutes up to 30 minutes after intravenous administration of 0.15 mg of clonidine. The following significant maximal mean effects were noted at about 15 minutes after the administration of clonidine: the heart rate decreased 12 percent (59 vs 52 beats per minute); and the atrioventricular conduction capacity (ie, paced heart rate at second-degree atrioventricular block) decreased by 9 percent (132 vs 121 beats per minute), while the maximal recovery time of the sinus node increased by a factor of two (1,704 vs 3,562 msec) when atrial overdrives of 120, 150, and 200 beats per minute were used for each five minute period. In analyzing maximal carotid sinus pressure slowing after administration of clonidine, three of 11 patients developed hypersensitive carotid sinus reflex de novo, and two patients showed a decrease and three patients an increase of carotid sinus pressure slowing, while three patients had no carotid sinus pressure slowing both before and after administration of clonidine. We conclude that caution should be taken in administering clonidine to patients with signs indicative of dysfunction of the sinus node.

Aged↗
PubMed1980

[Lowering the heart rate in tachycardiac atrial fibrillation by beta receptor blockade].

The effects of the long-acting beta-receptor blocking agent Nadolol on ventricular rate was evaluated by Holter monitoring in 14 patients with chronic atrial fibrillation, in whom no effective control of heart rate could be obtained by digitalis only. There was a significant drop of heart rate after the treatment with 2 times 60 mg Nadolol daily to 70% of control values (ten patients treated for one week). Treatment with 120 mg Nadolol once daily proved to be equally effective in four patients. Reduction of heart rate was most marked in periods of physical activity, while there was only a small effect during periods of rest.

Adrenergic beta-Antagonists↗
PubMed1977

Functional properties of mahaim fibers.

Electrophysiological studies were performed in a patient with a short P-R interval and a small delta wave. The findings suggest that ventricular pre-excitation resulted from an infranodal bypass (Mahaim type). As the functional properties of the pathway were evaluated, impaired conductivity (suggested by rather long refractory periods) became apparent at frequency stress. The pathway could easily be blocked by Ajmaline. This demonstrated an unexpected early diastolic improvement in conductivity; i.e. a supernormal phase of conduction. Due to this supernormal phase, Mahaim-fiber conduction was present when block in the anterior division of the left bundle branch, or even trifascicular block occurred. Thus the effects of exclusive Mahaim-fiber conduction on ventricular activation were documented.

Adult↗
PubMed1977

[Efficiency of patients with chronic renal failure (author's transl)].

In 77 patients with chronic renal failure - all were conservative treated - exercise-tests were performed with the bicycle and in 67 cases spiro-ergometric tests. We found a correlation between the decrease of hemoglobin and the decrease of efficiency and a linear function between the decrease of hemoglobin and the increase of creatinin in serum. There was no direct correlation between the increase of creatinin and the decrease of efficiency. The efficiency, measured in Watt, and the oxygen pulse correlated. More patients with hypertonia exceeded the level of 70 of the quotient heart volume/oxygen pulse but those with normal pressure. The efficiency was reduced in general: only 13,4% obtained 100 Watt, 28,4% 75 Watt and the rest of 58,2% were of bad efficiency and performed only 50 Watt or less.

Cardiac Volume↗
PubMed1977

[A controlled clinical study of early mobilisation of patients with myocardial infarction (author's transl)].

This is the report about 265 patients with recent transmural myocardial infarction. In the first week of hospital treatment 63 died. From the remaining 201 patients 101 fulfilled the conditions for early mobilisation of the WHO. In a controlled study these patients were divided in 2 groups: group 1 started the programme of early mobilisation the 7th day and group 2 was the control group which was mobilized after 3 weeks of bed rest. The 2 groups were comparable in the clinical course and had 2% of letality. The remaining 100 patients with conditions against early mobilisation were conservatively treated with 3 weeks of bed rest. The letality in this group was very high with 23%.

Age Factors↗