Search PubMed⌕ Search

Biomedical subjects

L Seipel

Publications and source records attributed to L Seipel.

At least 181 records · Page 10Linked to original sources
PubMed1983

[Sinus node suppression by ventricular stimulation in retrograde block].

In a patient with a sick-sinus syndrome atrial pacing revealed an abnormal prolongation of the sinus node recovery time. During ventricular pacing no retrograde ventriculoatrial conduction could be detected. In spite of this, complete atrial standstill occurred reproducibly during fixed-rate ventricular pacing. After ventricular pacing was stopped a pause of some seconds ("overdrive recovery") was observed before the reoccurrence of normal sinus rhythm. We have no explanation for this unique finding, unless concealed ventriculosinoidal conduction is postulated.

Electrocardiography↗
PubMed1983

[Effect of valve type and valve function on chronic intravascular hemolysis after alloprosthetic mitral and aortic valve replacement].

In 1091 patients with isolated Björk-Shiley, Lillehei-Kaster, Starr-Edwards, and St. Jude Medical mitral and aortic valve replacement, hemolysis parameters were determined (hemoglobin, LDH, haptoglobin, free plasma hemoglobin, reticulocyte count, serum bilirubin, transferrin, urine hemosiderin, schistocyte count). In 1006 of these patients no valve dysfunction was detected, while in 85 patients either paravalvular leakage or a thrombosis of the prosthetic valve was present. Haptoglobin was the most sensitive parameter for detecting even mild intravascular hemolysis, which was present in two-thirds of patients after alloprosthetic heart valve replacement. For quantifying red cell damage LDH was useful. Hemolysis was somewhat higher after Lillehei-Kaster and Starr-Edwards than after Björk-Shiley or St. Jude Medical implantation. The variance of LDH levels can be explained in a high percentage by correlating them with the hemodynamic findings at rest and exercise, which are indirect parameters of velocity profiles. Hemolysis is higher after aortic than after mitral valve replacement, with the exception of St. Jude valves. In patients with perivalvular leakage or valve thrombosis, red cell damage is more pronounced than in normally functioning prostheses (p less than 0.0005). When the hemolysis characteristics of the individual types of prosthesis are taken into account, the degree of hemolysis is a reliable indicator (p less than 0.05) of the functional integrity of the prosthesis. However, the degree of hemolysis does not correlate with the hemodynamic significance of perivalvular regurgitation.

Adolescent↗
PubMed1983

Central hemodynamics at rest and during exercise after mitral valve replacement with different prostheses.

To compare the hemodynamic features of different prosthetic heart valves that have equal tissue anulus diameter (29 mm or comparable), 75 patients with isolated mitral valve replacement (19 with Björk-Shiley Standard [BS], five with Hall-Kaster [HK], seven with Ionescu-Shiley [IS], 12 with Lillehei-Kaster [LK], 12 with Starr-Edwards [type 6120, SE], and 20 with St. Jude Medical [SJ] prostheses) were reexamined approximately 1 year after operation by right and left heart catheterization while they were at rest and during bicycle exercise. Mean pulmonary artery and mean left atrial pressure were reduced significantly in all the groups postoperatively. However, pulmonary artery and left atrial pressure were somewhat lower after BS and SJ implantation than the comparable pressures in the other groups. Normal values were reached only in a small number of patients, and the cardiac index remained at the lower limit of normal. Average diastolic pressure gradients in patients at rest were 2.3 +/- 0.6 mm Hg after SJ, 4.5 +/- 1.6 after BS, 5.2 +/- 3.3 after HK, 5.3 +/- 1.6 after IS, 7.1 +/- 1.3 after LK, and 6.3 +/- 2.0 after SE implantation. Effective valve orifice areas were calculated to be 3.1 +/- 0.8 cm2 in the SJ group and 2.2 +/- 0.5 cm2 in the BS group and even smaller in the other groups. Total volume loss does not seem to be significantly different among the valve types reexamined as determined by left ventricular angiography. For hemodynamic reasons, of all those prosthetic valves we compared, the SJ prosthesis appears to perform best in terms of lowest pressure gradients and largest effective orifice areas.

Adolescent↗
PubMed1983

Late complications in patients with Björk-Shiley and St. Jude Medical heart valve replacement.

Valve-related complications after Björk-Shiley mitral valve implantation (n = 475), aortic valve implantation (n = 424), or mitral-aortic valve implantation (n = 119) were compared with those after St. Jude Medical mitral valve replacement (n = 173), aortic valve replacement (n = 152), or mitral-aortic valve replacement (n = 69). All patients were placed on anticoagulant therapy with phenprocoumon early after operation. All patients had a comparable follow-up time of approximately 23 months, which showed that cumulative thromboembolic rates were significantly higher after St. Jude valve implantation than after Björk-Shiley valve implantation. Reoperations were necessary because of valve thrombosis (0.46%), perivalvular leakage (2.2%), or prosthetic valve endocarditis with perivalvular regurgitation (0.46%). One Björk-Shiley mitral valve prosthesis had to be replaced because of fracture of the outlet strut. Without significant intergroup differences, hemorrhage due to anticoagulant treatment was the most frequent complication. Thromboembolic complications were significantly more frequent after Björk-Shiley mitral, aortic, and double valve replacements than after St. Jude valve implantation. This may lead to consideration of changes in the prophylaxis of thrombus formations in the St. Jude valve, especially in aortic valve replacements, in patients with sinus rhythm.

Adolescent↗
PubMed1982

Effects of antiarrhythmic surgery on late ventricular potentials recorded by precordial signal averaging in patients with ventricular tachycardia.

In seven patients with documented ventricular tachycardia (VT) and prior myocardial infarction, late potentials (LP) were recorded at the end of or after the QRS complex from the body surface using high-gain amplification and the signal averaging technique (RC filter settings 100 to 300 Hz). In 6 to 7 patients VT could be initiated by programmed right ventricular stimulation; in one case, VT was inducible only from the left ventricle during surgery. Surgery was guided by epi- and endocardial mapping. In most cases besides resection of scar tissue, a partial or complete subendocardial encircling ventriculotomy was performed. Postoperatively, LPs were abolished in five cases, VT being no longer inducible. In the remaining two patients, LPs were still present. VT was still inducible in one of these two cases whereas in the other case, no programmed testing was done postoperatively. These data suggest that the abolition of LPs by surgery is closely related to the disappearance of the propensity to stimulus-induced VT. Thus, the averaging technique represents a new approach to the noninvasive control of the efficacy of surgery in patients with VT and prior myocardial infarction.

Adult↗
PubMed1982

Prevalence of late potentials in patients with and without ventricular tachycardia: correlation with angiographic findings.

Late potentials occurring at the end of or after the QRS complex were searched for from the body surface using high gain amplification and signal averaging techniques with filter settings between 100 and 300 hertz. The number of repetitions of the averaging process ranged between 150 and 300. Two hundred thirty-six patients were studied. In 27 control subjects, no late potentials were recorded. Among 146 patients without ventricular tachycardia or fibrillation, late potentials were present in 49 (34 percent). The mean duration of late potentials was 31 +/- 15.3 ms (median 25). Of 63 patients with documented ventricular tachycardia or fibrillation, 45 (71 percent) had late potentials (mean duration 51 +/- 31.5 ms; median 50) (probability [p] greater than 0.001). There was a close correlation between the detection of late potentials and left ventricular function. Late potentials occurred more frequently in patients with than in those without ventricular akinesia or aneurysm and in patients with than in those without ventricular tachycardia or fibrillation. In conclusion, late potentials are a frequent finding in patients with regional contraction abnormalities, both in patients with and in those without documented ventricular tachycardia. The greater prevalence and longer duration of these signals in patients with ventricular tachycardia or fibrillation might be responsible for the greater susceptibility to ventricular tachycardia. Long-term follow-up studies will be necessary to assess the possible prognostic significance of late potentials in patients without previously documented ventricular tachycardia or fibrillation.

Angiocardiography↗
PubMed1982

Electrophysiological actions of calcium antagonists in the heart.

Electrophysiological studies have shown that Ca antagonists affect only cardiac structures in which impulse propagation is mediated by the slow channel, i.e., mainly the sinoatrial and atrioventricular nodes. In addition they may depress abnormal slow conduction in diseased fibers. Ca antagonists do not represent a homogeneous group as different compounds seem to have different electrophysiological actions. In man, Ca antagonists normally have no significant effect on sinus node function. However, in patients with sinus node dysfunction, the same drugs may induce dangerous bradycardia or sinoatrial block. These different effects seem to be at least in part due to the different responsiveness of the normal and diseased sinus node to changes in autonomic tone via the baroreceptor reflex. In the A-V node, conduction and refractoriness are prolonged by each Ca antagonist to a different degree. In this regard, D 600 and verapamil have a very strong effect, whereas nifedipine in normal doses does not influence A-V nodal conductivity, and tiapamil and diltiazem have an intermediate position between these extremes. The results may have clinical relevance for antiarrhythmic therapy with Ca antagonists. In addition, they can help to avoid dangerous side effects in patients with disease of the sinus or A-V node.

Atrioventricular Node↗
PubMed1982

[Electrophysiological findings and follow-up in patients with syncope (author's transl)].

92 patients (mean age 54 +/- 14.7 years, 54 men) with unexplained syncopes were investigated by Holter monitoring, exercise testing and His-bundle-electrography (high-rate and programmed atrial stimulation). The diagnoses on 43 patients were sinus node dysfunction, in 32 cases atrio and/or intraventricular block, and in 6 patients idiopathic atrial fibrillation, whereas 8 patients had a history of ventricular tachycardia, 48 patients received a pacemaker (mean age 58 +/- 12.9 years), and 44 patients were discharged without a pacemaker (mean age 49 +2- 15.6 years). The mean duration of follow-up was 56 +2- 17.1 months. There were 13 deaths, 9 patients died from heart failure, 1 died suddenly, and 3 patients died from non-cardiac causes. 7 patients were lost to follow-up. 54 patients had no syncope any longer, while in 18 cases syncope was still present, 14 patients without pacemaker and 4 patients with pacemaker still had attacks. The cardiac mortality was 18.8% (with pacemaker) and 2.3% (without pacemaker). The only sudden cardiac death was observed in a patient with pacemaker. This study shows that pacemaker implantation bases on electrophysiologic study is able to improve symptoms in patients with syncope. However, the long-term prognosis of the patients is mainly depending on the severity of their underlying heart disease.

Adult↗
PubMed1982

[Effect of flecainide on chronic ventricular arrhythmias (author's transl)].

After an initial pilot study in five patients, the effect of flecainide on chronic ventricular arrhythmias was tested during 48-hour oral administration of 250 mg twice a day in nine further patients with previously drug-resistant chronic, stable ventricular arrhythmias. Mean age was 45.9 +/- 14.9 years; seven patients were male. Three patients had coronary artery disease, whereas the diagnoses in the remaining patients were congestive cardiomyopathy, aortic stenosis or no apparent heart disease. Continuous Holter monitoring with quantitative evaluation was performed in all patients for 24 hours before and during a two days' period of treatment. The mean number of ventricular ectopic beats decreased from 20.3 +/- 6.4 beats/min during hour six of treatment and further to 3.1 +/- 7.7 beats/min during hour 25 to 48 after onset of treatment. In either of nine patients, the mean decrease in ventricular ectopic rate was 97.5%. In only one patient, therapy was ineffective, Ventricular couplets were completely suppressed in six of eight cases. Looking at the spontaneous variability of ventricular ectopic beats during the control period, eight of nine patients showed a decrease which considerably exceeded the statistically necessary one. Headache of moderate degree was reported in one case in the pilot study. Therapy had to be stopped after the first dose because of QRS widening in another patient. In conclusion, this short-term study suggests that flecainide may be an effective drug for the management of ventricular arrhythmias.

Adult↗
PubMed1982

[Response of ventricular late potentials after surgical therapy of ventricular tachycardia].

19 patients with either previously documented sustained ventricular tachycardia (VT) (n = 16) or only inducible VT (n = 3, one of whom had recurrent syncope), due to previous myocardial infarction were studied pre- and postoperatively. Mean age was 53 +/- 6 years, 16 were male, 3 female. In all but one, VT could be induced preoperatively by programmed right ventricular stimulation. Late potentials (LP) were recorded at the end of or after the QRS-complex from the body surface using high-gain amplification and the signal averaging technique (RC-filter settings 100 to 300 Hz). Indication for surgery was either intractable VT or bypass grafting and/or aneurysmectomy. Preoperatively, mean duration of late potentials was 54 +/- 37.7 ms, mean amplitude was 12 +/- 14.0 mean V. Surgery was guided by epi- and endocardial mapping. In 14 cases endomyocardial encircling ventriculotomy was the main procedure, whereas in 5 patients only aneurysmectomy and bypass grafting were performed. Postoperatively, late potentials were no longer detectable in 12 cases, whereas in 6 of 7 cases there was a decrease in duration, but no essential change in amplitude. A postoperative electrophysiological study was performed in 18 cases. In those 12 patients with abolition of LPs, the maximal number of inducible ventricular echo beats using an extended stimulation program from three right ventricular sites, ranged between 1 and 5 in 9 cases, between 10 and 11 VE in 2 cases, whereas VT was induced in only 1 case. In 6 patients in whom LPs were still detectable, ventricular tachycardia could still be induced in 2 cases and a maximal response of ten echo beats was observed in another patient. Abolition of LP by surgery is closely related to the disappearance of the propensity to stimulus-induced VT. Thus the averaging technique may provide a non-invasive procedure to assess the successful outcome after operation for ventricular tachycardia. If, however, LPs are still present, this does not exclude successful surgical abolition of the propensity to ventricular tachycardia.

Cardiac Pacing, Artificial↗
PubMed1982

[Electrophysiological effects of flecainide on stimulus-inducible ventricular tachycardia].

13 patients (54 +/- 11.8 years) with either spontaneously occurring ventricular tachycardia (N = 12) or recurrent syncope (n = 1) probably due to ventricular tachycardia were studied electrophysiologically. In all patients, ventricular tachycardia could be initiated by programmed right ventricular stimulation during the control study. Ventricular tachycardia was sustained in eleven patients and non-sustained in the remaining two. After several days of oral administration of flecainide (400 to 500 mg per day) sustained ventricular tachycardia could still be initiated in seven cases that had to be interrupted by overdrive stimulation in five cases, and by cardioversion in the remaining two. In six cases, short, self-terminating episodes of ventricular tachycardia were induced. In four patients, induction of ventricular tachycardia was unchanged or made easier, whereas in seven cases ventricular tachycardia was more difficult to induce (i.e. later during the step-like stimulation program). The mean rate of induced ventricular tachycardia decreased from 215 +/- 59.4/min (+/- S.D.) to 169 +/- 44.1/min during flecainide (p less than 0.025). The interval between the tachycardia-initiating beat and the first beat of tachycardia increased from 323 +/- 61.1 ms to 438 +/-148.3 ms (P less than 0.02). The effective refractory period of the right ventricle was prolonged from 240 +/- 20.5 ms t 279 +/- 37.3 ms (P less than 0.005). The plasma concentration of flecainide at the time of stimulation was 995 +/- 238 ng/ml. Thus, flecainide exerts a marked effect on the rate of induced ventricular tachycardia, whereas the mode of induction did not change considerably. The prophylactic effect of long-term therapy with flecainide in patients with recurrent ventricular tachycardia needs further studies.

Adult↗
PubMed1982

The surgical treatment of ventricular tachycardias. Simple aneurysmectomy versus electrophysiologically guided procedures.

Between 1971 and 1982, 41 patients were operated upon for recurrent sustained ventricular tachycardia. All but three had severe coronary artery disease with a history of myocardial infarction. In 10 patients (Group I) simple aneurysmectomy with or without aorta-coronary bypass grafting was done. Thirty-one patients (Group II) had an electrophysiologically guided procedure, mainly partial or complete encircling endocardial ventriculotomy (EEV) at the earliest source of electrical activity during ventricular tachycardia. The results in the two groups indicate a clear superiority of electrophysiologically guided procedures over a simple aneurysmectomy regarding early and late disappearance of tachycardiac rhythm problems (p = 0.01); the differences between the two groups in hospital mortality (p = 0.43) and long-term survival are not significant. We compared our data with results in 160 cases of simple aneurysmectomy and 224 cases of electrophysiologically guided operations recently published in the literature. This comparison confirms the higher efficiency of mapping-guided procedures in eradicating ventricular tachycardias. The improvements in hospital and long-term survival, again, are not significant.

Adult↗