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Biomedical subjects

M Schlepper

Publications and source records attributed to M Schlepper.

At least 145 records · Page 8Linked to original sources
PubMed1980

[Reproducibility of sinus node recovery time in relation to the time of the day and the overdrive stimulation rate (author's transl)].

Corrected sinus node recovery time (CSRT) was tested in 9 patients with (CSRTI) and 6 patients without sick sinus syndrome = SSS (CSRTII) at 6 constant time intervals each, on 3 consecutive days using 5 rates of atrial overdrive stimulation (AST) via a stable loop mounted atrial electrode. From the results presented it can be concluded: CSRTI is reproducible with high rates when corresponding time periods and the same AST rate are used. A stepwise CRST increase by 60% is consistent up to AST 140 bpm only; up to AST 200 bpm the pattern varies within maximal pathological CSRT ranges for each of the 6 time periods measured, as an expression of influences unidentified in this study. The implication is: For an optimal diagnostic yield in CSRT testing several AST rates above 140 bpm are required and the time intervals of 17 and 8 hours represent a "high" and at 14 hours a "low" for CSRT testing; there are factors, other than the sinus node dysfunction, that added to the pathologic significance of the CSRT.

Adult↗
PubMed1980

Red blood cell aggregation in men with coronary artery disease.

The red blood cell aggregation value (AW) in a group of 39 patients with coronary artery disease (CAD) was measured and compared with that of an age- and sex-equivalent group of normals and a group of 12 patients with suspected CAD, whose coronary arteries were found to be normal by coronary arteriography. The AW was significantly higher in CAD patients than in both normal groups (2P < 0.01 and 2P < 0.02 respectively). The AW in a group of 12 CAD-patients treated with the aggregation lowering drug clofibrate was significantly lower than in the untreated CAD-group. The predictive value of AW was calculated by means of mathematical methods. Measurement of AW could be a useful aid in the study of detection of CAD.

Adult↗
PubMed1980

[Echo parameters of chronic aortic regurgitation (author's transl)].

Staging and timing of aortic-valve replacement, with respect to long-term prognosis is crucial in patients with isolated chronic aortic regurgitation (AR). To compare angiographic and M-mode echocardiographic parameters we echoed 39 patients one day before cardiac catheterisation: The angiography was used to divide the collective into four grades (G I-G IV). End-diastolic volume (EDV), stroke volume (SV) and regurgitant volume (RV) were used as echo parameters of the left ventricular volume, ejection fraction (EF) and circumferential fiber shortening (VCF) as parameters of left ventricular function. AR of G II and G III could be differentiated by an increase of EDV from 145 +/- 28.2 to 304 +/- 33.5 ml (p < 0.001), whereas EDV in G I-G II were similar to normal and G IV was similar to G III. EF and VCF were able to differentiate G III and G IV by a decrease from 67 +/- 8% to 54 +/- 7% (p < 0.001) and 1.01 +/- 0.24 to 0.88 +/- 0.31 (p < 0.01) respectively. Thus echo measurements predicted AR greater than G II from an increase of the EDV by more than 110% and a regurgitant volume of more than 3 1/min. G III and G IV could be differentiated by EF und VCF. These quantitative echo parameters were highly sensitive (92%) and specific (96%) whereas all other M-mode echo signs (oscillations of the mitral valve leaflet and interventricular septum, amplitude of oscillations, aortic root diameter, diastolic separation of the cusps) could be used only as qualitative indices, some with high specificity. Echocardiography allows a non-invasive assessment of the severity of AR based on parameters of left ventricular volume and function and thereby assist the accurate timing of aortic valve replacement.

Adult↗
PubMed1979

Heart valve replacement with the St. Jude medical prosthesis -- first clinical results --.

Starting in February 1978 52 St. Jude Medical Prostheses have been implanted in 47 patients (age 13--73 years) in aortic, mitral and tricuspid positions. Perioperative death occurred in 3 cases. Post mortem examination of these patients showed unimpaired valvular function. There were no other complications in an accumulated total valve time of approximately 300 months. Prior to surgery and post-operatively, several hemolytic parameters were analyzed. There was only a mild elevation in Serum LDH (285 +/- 10 iV/L). Fifteen patients underwent recatheterization 3 months postoperatively. The mitral valves did not reveal an enddiastolic gradient at rest, while the aortic valves had a peak to peak gradient of 8 +/- 2.1 mmHg. A standardized stress consisting of an infusion of isoproterenol was used. The results were compared to results obtained in patients with Björk-Shiley prostheses under identical conditions and did not show a significant difference. The preliminary hemodynamic findings correlate with preceding in vitro results and preclinical data, and the first clinical experience is promising.

Adolescent↗
PubMed1979

Failure of aneurysmectomy to improve left ventricular function.

Biplane left ventricular angiography was performed in 22 patients with isolated obstructive disease of the anterior descending branch of the left coronary artery and with an anterior aneurysm following transmural myocardial infarction. Six patients were restudied between 6 and 10 months after aneurysmectomy. Left ventricular reserve was estimated by analysis of a spontaneous postextrasystolic beat. Using angiographic techniques a contractile section, a transitional section, and a noncontractile section were identified. From the surgical patients the excised aneurysm and a transmural needle biopsy of the transitional section were investigated by light microscopy. With increasing volumes of noncontractile and transitional sections, total end-diastolic volume (r = 0.81, P less than 0.001) and end-systolic volume (r = 0.94, P less than 0.001) increased linearly, while the ejection fraction decreased (r = 0.70, P less than 0.001). No relation was found between the combined volumes of the noncontractile and transitional sections on the one hand, and the end-diastolic volume, the end-systolic volume, or the ejection fraction of the contractile section on the other hand. After aneurysmectomy a significant decrease was found in end-diastolic volume (194 to 133 ml/m2, P less than 0.001) and end-systolic volume (124 to 83 ml/m2, P less than 0.001) but no change occurred in ejection fraction (35 to 37%) and left ventricular end-diastolic pressure (23 to 25 mmHg). Surgical resection included part of the transitional section, which before surgery had an average ejection fraction of 27 per cent during a normal beat, rising to 41 per cent in a postextrasystolic beat. The transitional section after surgery now formed a large akinetic area of the anterior wall. We conclude that aneurysmectomy in isolated left anterior descending artery disease with anterior aneurysm fails to improve left ventricular function because the effect of reduction of left ventricular volumes is offset by the destruction of contractile behaviour in the transitional section.

Adult↗
PubMed1979

Impaired left ventricular function in chronic aortic valve disease: survival and function after replacement by Björk-Shiley prosthesis.

Postoperative survival and left ventricular function were studied in 128 patients who underwent isolated aortic valve replacement by the Björk-Shiley valve between 1973 and 1977. The average follow-up was 2.1 years. Patients with associated coronary artery disease or mitral valve disease were excluded. Preoperative ejection fraction ranged from 15-84%. Forty-two patients were restudied by cardiac catheterization 9.1 +/- 1.1 months (mean +/- SEM) after valve replacement. The hospital mortality was 11%. Preoperative type of valve lesion, functional class, cardiothoracic ratio, and ejection fraction (EF) had no significant effect on postoperative survival up to 4 years. After operation, left ventricular mass (LVMI) and peak systolic wall stress (PSWS) fell significantly, while EF and mean normalized systolic ejection rate (MNSER) increased in aortic stenosis and in aortic insufficiency. Neither in aortic stenosis nor in aortic insufficiency was there a significant relation between preoperative ejection fraction and postoperative LVMI, EF, MNSER and PSWS. We attributed this to a marked improvement of left ventricular function in patients with preoperative impaired ventricular function. Six patients with paravalvular leak to restudy has a significantly lower EF and MNSER, and a higher PSWS than patients without leak. Patients without leak had normal EF, MNSER and PSWS when compared with 10 normal persons, but LVMI remained moderately elevated. Postoperative transprosthetic gradient was 11.9 mm Hg (range 0-64 mm Hg). We conclude that impaired cardiac function is completely restored after aortic valve replacement by Björk-Shiley valve, if valve function is good. Patients with impaired cardiac function preoperatively did not have a poorer prognosis after operation than patients with normal function.

Adolescent↗
PubMed1978

Haemodynamic effects of supraventricular tachycardias and their alterations by electrically and verapamil induced termination.

The haemodynamic effects of electrically initiated supraventricular tachycardias were studied in 10 otherwise healthy patients. With the beginning of the dysrhythmia there was a sharp decrease of systemic arterial and left ventricular systolic pressure, dP/dtmax, cardiac index, and stroke volume. Then, these parameters except stroke volume exhibited an increase, but were statistically different from control until the tachycardia was electrically stopped at the tenth minute. Mean pulmonary artery pressure rose steadily and remained on an elevated level which was reached between the third and fifth minute. After cessation there was a short augmentation of systemic arterial and left ventricular systolic pressure as well as of dP/dtmax and cardiac index. Mean pulmonary artery pressure steadily decreased and for all parameters control values were reached at about the third minute. When the tachycardia was terminated at about the same time by an i.v. injection of 10 mg of verapamil the 'post-tachycardial potentiation' was less marked or even absent. Mean arterial and left ventricular pressure was lower and mean pulmonary artery pressure remained elevated as compared with the values observed after electrical termination. Cardiac index and dP/dtmax showed no significant differences. It can be concluded that verapamil in a dosage sufficient to terminate the arrhythmia did not exhibit additional negative inotropic effects.

Adult↗
PubMed1978

Recovery from myocardial failure after aortic valve replacement.

Left ventricular hypertrophy and function were studied in 27 consecutive patients with chronic aortic valve disease before and 6.4 +/- 2.2 (S.D.) months after aortic valve replacement with Björk-Shiley prostheses. Four patients were excluded because of postoperative paravalvular regurgitation. Five patients had aortic stenosis (AS), seven patients AS plus insufficiency (AS-AI), and 11 patients aortic insufficiency (AI). Left ventricular muscle mass (LVMI), ejection fraction (EF), mean circumferential fiber shortening rate (VCF), mean normalized systolic ejection rate (MNSER), and peak systolic wall stress (PSWS) were determined angiographically. LVMI fell significantly after corrective surgery, whereas EF, VCF, and MNSER increased. PSWS decreased after the operation. Comparison of stress ventriculograms before and after surgery in six patients with predominant AS (isoproterenol infusion, 0.3 microgram per kilogram of body weight per minute) showed an increase of EF, VCF, and MNSER and a decrease of PSWS. We conclude that hypertrophy in chronic aortic valve disease regresses after aortic valve replacement, and thereby depressed cardiac function and reserve recover.

Adult↗