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Biomedical subjects

L Seipel

Publications and source records attributed to L Seipel.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1988

[Comparison of the hemodynamics effects of D-sotalol and D,L-sotalol].

The hemodynamic effects of the class III drug D-sotalol and of the beta adrenergic receptor antagonist D,L-sotalol were compared in 16 rats (2 mg/kg i.v.). A group with NaCl-infusion served as control (n = 10). Besides measurements in the intact circulation isovolumic registrations were performed to examine the left ventricular myocardial function without interferences. D,L-sotalol significantly reduced the dp/dtmax (61%) and the peak isovolumic left ventricular pressure (64%). It lowered the heart rate by 13% and slightly increased the mean aortic pressure to 107% (p less than 0.05). D-sotalol, in contrast, caused only a very transient reduction of the dp/dtmax and was comparable to the controls already 5 min after injection. The results demonstrate, that the D-enantiomer is largely avoid of the hemodynamic effects of the racemic D,L-sotalol after intravenous injection.

Animals↗
PubMed1988

Accuracy of Doppler echocardiography in quantification of left to right shunts in adult patients with atrial septal defect.

In previous experimental and pediatric studies, the ratio of pulmonary to systemic flow (Qp/Qs) was accurately estimated by Doppler echocardiography in various cardiac shunt lesions. The purpose of this study was to assess the accuracy of pulsed Doppler echocardiography in determining the magnitude of shunt flow in adult patients with an ostium secundum type atrial septal defect. In 32 patients with high quality echocardiograms and excellent Doppler signals, blood flow was measured in the right and left ventricular outflow tract by Doppler echocardiography. In 16 patients without heart disease, the correlation (r) between systemic (Qs) and pulmonary (Qp) blood flow was 0.96 (SEE = 0.417 liter/min, y = 1.05x - 0.21) and the mean Qp/Qs ratio was 1.01 +/- 0.09. In 16 patients with an atrial septal defect, the Qp/Qs ration measured by oximetry ranged from 1.34 to 4.61 and by pulsed Doppler echocardiography from 1.31 to 4.46 (p = NS). In these 16 patients, the correlation between the Qp/Qs ratio determined by oximetry and pulsed Doppler echocardiography was significant (r = 0.82, SEE = 0.54). In the total group of 32 patients, the correlation was stronger (r = 0.93, SEE = 0.37). Systematic differences between the invasive and noninvasive shunt calculations did not occur. Thus, in adult patients with an atrial septal defect of the secundum type and high quality echocardiograms, the magnitude of left to right shunt can be accurately assessed by pulsed Doppler echocardiography. In the absence of pulmonary hypertension, pulsed Doppler echocardiography provides precise information for the decision to undertake conservative or operative treatment.

Adult↗
PubMed1988

Effects of graded intensity of oxygen deficiency on function and energy metabolism in post-ischaemic myocardium.

The effect of graded ischaemic injury on post-ischaemic myocardium was examined in rat hearts after three 4 min periods of asphyxia. Systolic function under steady state conditions and during isovolumic beats, the content of high energy phosphates and glycogen, and myocardial material properties were determined. Severity of the oxygen deficiency was varied by manipulating myocardial oxygen demand (MVO2) either by rapid atrial pacing or by vagal stimulation. After 20 min of post-asphyxial recovery, steady state haemodynamics were almost normal. In the high MVO2 group (atrial pacing) the dp/dtmax was reduced to 90%(NS). The isovolumic indices of function were decreased in all post-asphyxial groups. This was most pronounced in the high MVO2 group, with a reduction in peak left ventricular systolic pressure to 85.7 (SEM 3.4)% and a decrease in peak left ventricular systolic stress to 82.3(3.9)% (p less than 0.01). The post-asphyxial myocardial performance recovered better in the low MVO2 group (vagal stimulation). Material properties were altered only in the high MVO2 group. The decreased content of ATP and glycogen were comparable in all post-asphyxial groups. A phosphocreatine overshoot phenomenon was most marked in the high MVO2 group: 11.4(2.8) mumol.g-1 v 4.7(0.9) mumol.g-1 (control), p less than 0.01. The results indicate that post-ischaemic contractile dysfunction of reversibly injured is not closely related to the previous O2 deficit or to the functional impairment. We also obtained no correlation between ATP content and material properties in modestly injured post-ischaemic myocardium.

Animals↗