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Biomedical subjects

L Seipel

Publications and source records attributed to L Seipel.

At least 91 records · Page 5Linked to original sources
PubMed1990

[Effect of cibenzoline on atrial vulnerability and value of electrophysiological methods in the treatment of paroxysmal atrial fibrillation].

The effects of intravenous cibenzoline (1,5 mg/kg) on atrial vulnerability and electrophysiology were assessed in 25 patients with documented paroxysmal atrial fibrillation, in whom sustained (greater than 30 s) atrial fibrillation/-flutter was induced by programmed atrial stimulation. In seven patients atrial fibrillation persisted despite the application of cibenzoline; in eight patients induction of atrial fibrillation was not prevented. In 10 patients the induction of sustained atrial fibrillation was prevented by cibenzoline. Intraatrial conduction time and shortest ventricular cycle length during atrial fibrillation were increased by cibenzoline (p less than or equal to 0.01). The effective refractory period of the right atrium was not significantly affected. Eight patients with frequent episodes of paroxysmal atrial fibrillation received oral cibenzoline (320 mg/day) for control of paroxysmal atrial fibrillation irrespective of the efficacy of intravenous cibenzoline. Prevention of stimulation-induced atrial fibrillation predicted successful treatment of paroxysmal AF. In conclusion, cibenzoline might be effective in the treatment of atrial tachyarrhythmias. Programmed atrial stimulation seems to be helpful in the prediction of the efficacy of an antiarrhythmic treatment of paroxysmal atrial fibrillation.

Adult↗
PubMed1990

[Percutaneous coronary Excimer laser angioplasty in patients with coronary heart disease].

To verify the efficacy and safety of percutaneous coronary excimer laser angioplasty in patients with coronary artery disease a prospective study was conducted in 60 patients. The application of laser light was possible in 55 of the 60 patients. A novel 1.4-mm diameter catheter with 20 quartz fibers of 100-microns diameter, each arranged concentrically around a central lumen suitable for an 0.014-inch flexible guide wire was used. The light source was a commercial excimer laser emitting energy at a wavelength of 308 nm, with a pulse duration of 60 ns. The laser was operated at 20 Hz; mean energy transmission was 30 +/- 5 mJ/mm2. In 23 of the 55 patients treated with excimer laser energy the qualitative angiographic results were sufficient. In 32 patients additional balloon angioplasty was necessary, either because of an insufficient result or due to vessel closure after laser ablation. In 47 of the 55 patients control angiography was performed within the 6-month follow-up period. Rate of restenosis was higher in patients treated with laser ablation and subsequent balloon angioplasty (16 of 28) than in patients treated with laser ablation alone (6 of 19). Results of the 6-month observation period suggest that 1) coronary excimer laser angioplasty in combination with subsequent balloon angioplasty results in a considerable increase of the restenosis rate; 2) the exclusive use of laser ablation also results in a restenosis rate comparable to balloon angioplasty alone; and 3) the impact of this new method using improved application systems and higher energy transmission has to be determined in further studies.

Angina Pectoris↗
PubMed1989

Hemodynamic effects of antiarrhythmic drugs: negative inotropy versus influence on peripheral circulation.

The negative inotropic effect of nearly all antiarrhythmic drugs is one of the major drawbacks in antiarrhythmic therapy. This is particularly important in patients with reduced left ventricular function. In the clinical setting, different compounds have been described to depress cardiac function to a variable extent. The results are not uniform. In an experimental model, the hemodynamic effects of different drugs in the intact circulation as well as under isovolumic conditions in vivo after short cross-clamping of the aorta were tested. The results indicate that all antiarrhythmic compounds with the exception of class III drugs have a similar negative inotropic action on the heart muscle. However, the drugs have different effects on peripheral resistance, thus influencing cardiac afterload. These differences seem to be responsible for the different hemodynamic effects of the drugs observed clinically.

Animals↗
PubMed1989

Percutaneous coronary excimer laser angioplasty: initial clinical results.

A novel 1.3 mm diameter laser catheter, consisting of 20 concentric 100 microns quartz fibres around a central lumen for a 0.35 mm flexible guide wire, was used to ablate atherosclerotic tissue in thirty patients with coronary artery disease. The laser catheter was coupled to an excimer laser delivering energy at a wavelength of 308 nm and a pulsewidth of 60 ns. The primary success rate was 90% (27 of 30 lesions). The mean (SD) percentage stenosis fell from 85 (15)% to 41 (19)% after laser ablation. In ten patients the lumen diameter after laser angioplasty was considered sufficient, but subsequent balloon angioplasty was carried out for the other twenty patients. Failure to pass the lesion was caused by vessel kinking in two patients and a total occlusion in one patient. No complications directly attributable to laser ablation, such as vessel wall perforation, occurred; one dissection occurred but had no clinical sequelae. There was one early reocclusion and death in a patient with triple vessel disease and unstable angina, probably as a result of plaque rupture after balloon angioplasty. These results are encouraging and justify further clinical investigations.

Angioplasty, Balloon↗
PubMed1989

[Doppler echocardiography quantification of the regurgitant blood volume in patients with mitral valve insufficiency].

The purpose of this study was to assess the accuracy and clinical utility of pulsed Doppler echocardiography in determining the regurgitant fraction in patients with pure mitral regurgitation. In 30 unselected consecutive patients with mitral regurgitation and in 20 patients without valvular heart disease pulsed Doppler echocardiography was performed to measure blood flow at the mitral and aortic valve. The regurgitant blood volume was calculated as the difference of the stroke volumes measured at the mitral and aortic valve. The regurgitant fraction was computed as regurgitant blood volume/mitral flow. By cardiac catheterization regurgitant blood volume and regurgitant fraction were obtained from the left ventricular angiographic stroke volume and the stroke volume measured by thermodilution. Five patients were excluded because of technically poor left ventricular angiograms. In 4 patients with mitral regurgitation measurement of the regurgitant blood volume and regurgitant fraction was impossible by Doppler because of poor ultrasound signal quality. In 21 patients with mitral regurgitation the correlations between the invasive and the Doppler measurements were significant (regurgitant blood volume: r = 0.89, SEE = 20.9 ml; regurgitant fraction: r = 0.91, SEE = 7.1%). However, the mean percent error of the regurgitant fraction measurement (12.0 +/- 11.6%) was smaller than of the regurgitant blood volume measurement (24.9 +/- 17.0%). In the control group the regurgitant blood volume ranged between -25.1 ml and 11.6 ml and the regurgitant fraction between -17.7% and 12.4%. Thus, pulsed Doppler echocardiography is clinically useful in determination of the regurgitant fraction in 84% of unselected adult patients with pure mitral regurgitation. The Doppler method is limited in the diagnosis and quantification of mild regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Percutaneous transluminal excimer laser coronary angioplasty].

Percutaneous transluminal laser coronary angioplasty (PTLCA) was undertaken in five patients (four men and one woman, aged 44-72 years) with coronary artery stenosis. The vessel diameter was increased in all patients after PTLCA; complete ablation of the atheromatous plaque succeeded in three. In the other two the catheter could not be advanced across the entire stenotic region. After PTLCA the stenoses were 40-50% of normal lumen. Balloon dilatation was additionally done in all five patients. In three this caused dissection of the vessel wall distal to the stenosis and possible intracoronary thrombus formation: this would suggest that balloon dilatation after laser angioplasty is not recommendable. PTLCA widens the spectrum of invasive methods for treating coronary artery stenosis.

Adult↗
PubMed1989

Low-dose enalapril in severe chronic heart failure.

In a 3-month prospective, single-blind, controlled trial, 38 patients in New York Heart Association functional class III-IV were assigned to group E (n = 19): enalapril 5 mg/day in addition to the previous therapy with digitalis and diuretics, or group C (n = 19): continuation of the previous therapy. In group E, 79% of the patients improved by at least one NYHA functional class after 3 months. In group C, the functional class did not change and four patients died. The echocardiographically determined end-diastolic diameter of the left ventricle decreased in group E from 72 +/- 8 mm to 63 +/- 6 mm (p less than 0.001), and the scintigraphically determined ejection fraction of the left ventricle increased from 33 +/- 18% to 40 +/- 19% (p less than 0.002). In contrast, no significant change was found in group C. Plasma-renin activity increased in group E from 8.2 +/- 1.8 ng/ml h to 29.7 +/- 14 ng/ml h (p less than 0.001), and plasma aldosterone decreased from 47.7 +/- 7.6 ng/dl to 19.9 +/- 4.8 ng/dl (p less than 0.01). In group C no significant change occurred. Comparing the actual changes (deltas) of the NYHA functional class (p less than 0.02), end-diastolic diameter and ejection fraction of the left ventricle, plasma-renin activity, and plasma aldosterone (p less than 0.0001), a significant difference between the two groups was found. Thus, low-dose enalapril resulted in a significant improvement of the NYHA functional class in patients with severe chronic heart failure, accompanied by an improvement in left ventricular function and a decrease in secondary aldosteronism.

Aged↗
PubMed1989

Comparison of the effects of intravenous and oral betaxolol on antegrade and retrograde conduction in patients with atrioventricular nodal reentrant and atrioventricular reentrant tachycardia.

The electrophysiologic effects of intravenous (0.15 mg kg-1) and oral (20 mg day-1) betaxolol have been investigated in 11 patients with atrioventricular (A-V) nodal reentrant tachycardia and eight patients with orthodromic A-V reentrant tachycardia. Betaxolol significantly (P greater than 0.01) prolonged sinus cycle length, sinus node recovery time, intranodal conduction time, and the antegrade functional refractory period of the A-V node. When the effective refractory period of the A-V node could be determined it was increased by betaxolol, whereas no significant electrophysiologic effects were observed in the atrium, the ventricle or the accessory pathway. Intravenous betaxolol prevented tachycardia in 8 out of 11 patients with A-V nodal reentrant tachycardia, whereas oral betaxolol was effective in 10 patients, primarily by acting on the antegrade limb in two patients and on the retrograde limb in eight patients. In those with A-V reentrant tachycardia, intravenous betaxolol did not prevent tachycardia in any patient, while it was effective after oral treatment in two patients. When the tachycardia remained inducible, cycle length of the tachycardia increased in all patients, due to prolongation of the antegrade and retrograde conduction time in patients with A-V nodal reentrant tachycardia, and due to an increase in the antegrade conduction time, i.e. the A-V node, in the patients with A-V reentrant tachycardia. In conclusion, betaxolol proved to be effective in the treatment of supraventricular tachycardia; for chronic treatment, a single oral dose (20 mg) seems to suffice.

Administration, Oral↗
PubMed1989

[Successful treatment of stress-induced therapy refractory ventricular tachycardia with verapamil].

A 51-year-old woman was admitted to the hospital for further elucidation of a syncope of unknown origin and exercise-induced tachycardias with broad QRS-complex. The tachycardia was induced by bicycle exercise stress testing, had a frequency of 165/min, showed an inferior axis and left bundle branch block. Organic heart disease was excluded by right and left heart catheterization and selective coronary angiography. A nodoventricular bundle or an atrio-ventricular bundle was excluded by an extensive electrophysiologic study, therefore the documented tachycardia was probably of ventricular origin. However, it was not possible to induce a ventricular tachycardia by programmed ventricular stimulation with up to three extrastimuli even after the infusion of isoprenaline. Sotalol (2 x 160 mg/die) and the combined treatment with mexiletine (2 x 360 mg/die) and disopyramide (2 x 250 mg/die) did not prevent the induction of the tachycardia by exercise testing. The combination of sotalol and flecainide (2 x 100 mg/die) evoked complex ventricular arrhythmias at rest not noted before, and it was therefore withdrawn as well. After all antiarrhythmic drugs were withdrawn verapamil was given in a dose of 3 x 120 mg and this therapy reproduceably prevented the induction of ventricular tachycardia by exercise testing.

Anti-Arrhythmia Agents↗
PubMed1989

Circulatory and myocardial effects of different sodium antagonistic drugs in comparison to the calcium antagonist verapamil.

The hemodynamic effects of intravenous class I and class IV antiarrhythmic drugs were investigated at different doses in comparison. In open-chest rats hemodynamic measurements in the intact circulation and isovolumic registrations 5 min after infusion of flecainide (2, 4, 8 mg/kg), disopyramide (1, 2, 4, 8 mg/kg), quinidine (5 and 10 mg/kg) and verapamil (0.35, 0.7, 1.5 mg/kg) were compared to saline controls. After clinically usual doses all investigated drugs had no effects on stroke volume, cardiac output, dp/dtmax and systemic resistance. The isovolumic pressure generating capacity of the left ventricle was not decreased at these doses. High intravenous doses of the drugs, however, caused a significant depression of myocardial performance (pressure generating capacity). Furthermore, flecainide decreased mean aortic pressure and heart rate, while disopyramide had no significant effect on the peripheral circulation. Blocking of the autonomic system (1 mg/kg propranolol and 0.1 mg/kg atropine) did not change significantly the action of disopyramide. Quinidine lowered heart rate and pressures. Verapamil reduced the heart rate and tended to decrease the mean aortic pressure. Besides the negative inotropic action of high doses the different hemodynamic profiles of class I and class IV antiarrhythmic drugs might be of importance for intravenous application in patients with left ventricular dysfunction.

Animals↗
PubMed1989

[Doppler echocardiography measurement of the regurgitation fraction in patients with aortic valve insufficiency].

The purpose of this study was to assess the clinical utility of pulsed Doppler echocardiography in the determination of regurgitant fraction in patients with aortic regurgitation. Therefore, in 33 unselected consecutive patients with aortic regurgitation, and in 16 patients without heart disease Doppler echocardiography was performed to measure blood flow at the aortic and pulmonary valve. The regurgitant blood flow (RBV) was calculated as the difference of the stroke volumes measured at the aortic and pulmonary valve. The regurgitant fraction (RF) was computed as RBV/aortic flow. At cardiac catheterization RBV and RF were calculated from the left ventricular angiographic stroke volume and the stroke volume measured by thermodilution technique. Four patients were excluded because of technically poor left-ventricular angiograms. In eight patients with aortic regurgitation Doppler measurement of RBV and RF was impossible. The correlations between the invasive and the Doppler data were significant in 21 patients with aortic regurgitation (RBV: r = 0.87, SEE = 16.1 ml; RF: r = 0.90, SEE = 8.1%). However, the RF (41.6 +/- 17.6%) was overestimated by Doppler echocardiography (46.0 +/- 17.9%; p les than 0.021). In the control group RBV ranged between -8.1 ml and 10.5 ml and RF between -13.3% and 7.4%. Thus, pulsed Doppler echocardiography is clinically useful in determination of the regurgitant fraction in about 70% of patients with pure aortic regurgitation. The Doppler method, however, is limited in the diagnosis and quantification of mild aortic regurgitation.

Adolescent↗
PubMed1989

[Electrophysiologic properties of cibenzoline in Wolff-Parkinson-White syndrome and atrioventricular nodal reentry tachycardia].

The electrophysiologic effects of the new class-1 antiarrhythmic drug cibenzoline (1.5 mg/kg within 10 min, followed by an infusion of 0.5 mg for 30 min) were investigated in six patients with atrioventricular (av) nodal reentrant tachycardia and nine patients with atrioventricular tachycardia. Sinus cycle length, sinus node recovery time, effective refractory period (ERP) of the atrium and the ventricle as well as the ERP of the av node were not significantly affected by cibenzoline. Retrograde conduction via the av node was prevented by cibenzoline in 6/15 patients, retrograde ERP was increased in 4/15 patients and in 5/15 patients determination of the retrograde ERP of the AV node was impossible. Intranodal conduction time (AH-interval) and infranodal conduction time (HV-interval) was increased from 96 +/- 27 ms to 117 +/- 40 ms (p less than 0.01) and 36 +/- 12 ms to 62 +/- 12 ms (p less than 0.01), respectively. In four patients with antegrade conduction along the accessory pathway no antegrade conduction was seen after the application of cibenzoline. Retrograde ERP of the accessory pathway was increased in two patients, it was unchanged in three patients, and no retrograde conduction along the accessory pathway was seen in four patients. AV nodal reentrant tachycardia was not inducible, after cibenzoline in 4/6 patients and in 5/9 patients with AV reentrant tachycardia. If tachycardia remained inducible, an increase in tachycardia cycle length from 333 +/- 46 ms to 402 +/- 24 ms was observed (p less than 0.01). In conclusion the electrophysiologic effects of cibenzoline make it a suitable drug for the treatment of av nodal reentrant tachycardia and atrioventricular tachycardia.

Adult↗
PubMed1989

[Heart arrhythmia following surgery of congenital heart defects].

As a result of the intraoperative trauma sinus node dysfunction and AV conduction defects have been observed. In addition bifascicular block (RBBB with LAH) may occur after repair of a ventricular septal defect. This electrocardiographic pattern indicates a high risk of developing a trifascicular block only in those patients with reversible AV block in the early postoperative period. After closure of an atrial septal defect, atrial fibrillation can develop as well as ventricular tachycardia and fibrillation after repair of a ventricular septal defect. The latter seems to be the underlying mechanism of sudden cardiac death occurring late after operation, especially in patients with Fallot tetralogy. In addition to the scar, persistent structural myocardial changes seem to be an important factor. Electrophysiological investigation is indicated in all symptomatic patients especially for detection and treatment of ventricular tachyarrhythmias. However, there is yet no proof that sudden death can be prevented by antiarrhythmic treatment of all ventricular premature beats in the endangered patients.

Arrhythmias, Cardiac↗