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Biomedical subjects

L Seipel

Publications and source records attributed to L Seipel.

At least 271 records · Page 15Linked to original sources
PubMed1977

Sinus node recovery time and calculated sinoatrial conduction time in normal subjects and patients with sinus node dysfunction.

In 61 patients sinus node function was tested by programmed (sinoatrial conduction time, SACT) and overdrive atrial pacing (sinus node recovery time, SRT). In the control group (N = 20), mean sinus cycle length was 773 +/- 140.2 msec, mean absolute SRT 1044 +/- 215.8 msec [corrected SRT (CSRT) 270 +/- 112.5 msec; mean +/- SD] and calculated SACT was 82 +/-19.2 msec. The upper limit of normal SACT was defined as 120 msec. In 41 patients with sinus node dysfunction, mean age (55 +/- 14.7 years), mean spontaneous cycle length during the study (1094 +/- 248.0 msec), the lowest heart rate observed (42 +/- 7.5 beats/min), maximal SRT (2110 +/- 1269.1 msec), maximal CSRT (1016 +/- 1182.8 msec), and calculated SACT (126 +/- 47.3 msec) were significantly longer than in the control group. Abnormalities of sinus node function, as evidenced by the degree of spontaneous bradycardia, SRT and calculated SACT were more frequent in patients with bradycardia-tachycardia syndrome or spontaneous sinoatrial block than in those exhibiting isolated sinus bradycardia. We conclude 1) that in patients with sinus node dysfunction both sinus node automaticity and sinoatrial conduction may be abnormal, and 2) that overdrive and programmed premature atrial stimulation can separate patients with sinus node dysfunction according to their clinical presentation.

Adult↗
PubMed1977

[Long-term treatment with the new antiarrhythmic drug propafenone in correlation to plasma levels (author's transl)].

The results of long term oral therapy of cardiac arrhythmias in 43 patients successfully treated with propafenone are reported. The patients were treated for periods ranging between 1 month and 34 months with a mean of 13.4 months. The administered dose varied between 150 mg tds and 300 mg qds with an average daily dose of between 600 and 750 mg. The doses were decided on a body-weight basis with range of 6 to 17 mg/kg and an average of 12 mg/kg. Altogether 30 patients were successfully treated over a long period, sometimes in combination with other antiarrhythmic agents, particularly beta-blockers. 2 patients did not appear after some first controls. In 7 patients the drug was not effective, even when used in combination with others. 4 patients stopped the treatment due to side-effects. Further 18 patients complained temporarily of gastrointestinal and cerebral side-effects. Some Ecg changes were noted, particularly A-V conduction delays and spreading of the QRS-complex. We suggest that the clinically most important parameters for monitoring an antiarrhythmic regimen of propafenone are the patients's own history and Ecg-examination noting the PQ interval and particularly the width of the QRS-complex and long-term monitoring.

Adrenergic beta-Antagonists↗
PubMed1977

[Prognostic significance of arrhythmias in acute myocardial infarction (author's transl)].

Ventricular arrhythmias represent a common precursor of ventricular fibrillation in acute myocardial infarction in man. Frequent ventricular ectopic beats (greater than 5/min), multifocal ectopic beats, ventricular bigeminy, ventricular salvoes, ventricular tachycardia, and the R-on-T phenomenon have been considered as warning arrhythmias. However, recent studies have given rise to some doubt concerning the value of warning arrhythmias as predictors of ventricular fibrillation. In many a case there is no warning arrhythmia prior to ventricular fibrillation or these arrhythmias do not fulfill the criteria of warning arrhythmias. In other cases the warning arrhythmias develop so briefly before ventricular fibrillation that no prophylactic measure can be instituted. Warning arrhythmias may occur at equal frequency in patients with and without consecutive ventricular fibrillation. This also applies to the R-on-T phenomenon as a warning arrhythmia and as the initiating mechanism of ventricular fibrillation. In nearly half the cases ventricular fibrillation is initiated by a late ventricular ectopic beat. In view of these data of the literature, the so-called warning arrhythmias seem to have lost their predictive value. They represent a common phenomenon in acute myocardial infarction in man. However, ventricular fibrillation may also occur without any prior ventricular arrhythmias, above all during the first day of acute myocardial infarction. The frequency of ventricular fibrillation decreases in the course of infarction. Therefore the time during acute myocardial infarction may be a better guide whether to institute prophylactic antiarrhythmic therapy than the occurrence of ventricular arrhythmias. To date, the beneficial effect of prophylactic administration of lidocaine has remained controversial though a recent double-blind study has strongly suggested that lidocaine is able to prevent ventricular fibrillation. If these results should be confirmed by others, this would ask for routine administration of lidocaine in each case with acute myocardial infarction during the first day.

Acute Disease↗
PubMed1977

[Hemodynamic results after prothetic tricuspid valve replacement (author's transl)].

The hemodynamic results after prosthetic tricuspid valve replacement were investigated in 8 patients. One patient had myxoma in the right atrium with destruction of the tricupsid valve. 7 patients had multiple rheumatic valvular disease. In all these patients multiple valve replacement was performed. The pressure in the right and left atrium , the cardiac output, and stroke volume were determined in all cases at rest, in 5 patients also on exercise. Furthermore the subclavian venous blood flow was measured by Doppler ultrasound technique percutaneously. In all cases the pressure in the right atrium remained elevated after operation and increased on exercise with the increasing cardiac output. This pressure increase is due to an important obstruction of the prostheses to the blood flow. This could be demonstrated by determination of diastolic pressure gradients across the prostheses. In 5 cases the analysis of the pressure curves showed systolic elevation suspicious to tricuspid insufficiency. In all these cases a systolic regurgitation was seen in ultrasonic Doppler flow curves of the subclavian veins. This method seems to be of value in assessing tricuspid regurgitation after valve replacement. The hemodynamic results after prosthetic tricuspid valve replacement are unsatisfactory in most cases. Tricuspid valve replacement should be considered only in cases in whom valve-preserving procedures are not possible.

Adult↗
PubMed1977

[Evaluation of social status and hemodynamic results four to six years after prosthetic valve replacement (author's transl)].

In 72 patients the professional and social status before and after prosthetic valve replacement was examined. In 60 of these patients the hemodynamic data (cardiac index, stroke volume index, pulmonary arterial pressure at rest and during exercise) were measured. The patients were classified according to their professional training, their last occupation, and their social status before operation. Postoperative changes in professional life and the daily work load were correlated to the hemodynamic results. The study shows that the social status plays a more important role in regaining the professional position postoperatively than the hemodynamic parameter.

Adolescent↗
PubMed1976

His bundle recordings in a case of complete atrioventricular block combined with pre-excitation syndrome.

In a patient with complete A-V block suffering from attacks of dizziness an intermittent A-V conduction with a short P-R interval and a delta wave of the conducted ventricular complex were observed. After accelerating the sinus rate by atropine and by exercise, one-to-one conduction was established with QRS complexes of WPW type A configuration. His bundle recordings revealed a complete block within the normal conduction system at the level of the A-V node. A slow junctional rhythm with a normal H-V interval was activating the ventricle. During atrial pacing a one-to-one conduction through an accessory pathway could be documented at cycle lengths between 800 and 380 msec. sandwiched in between zones of complete block at smaller or longer cycle lengths. During ventricular stimulation no retrograde V-A conduction could be observed. The findings support the thesis of at least two functionally different A-V pathways in patients with pre-excitation syndrome.

Arrhythmias, Cardiac↗
PubMed1976

The effect of premature atrial depolarization on sinus node automaticity in man.

Sino-atrial conduction time (SACT) may be calculated from the difference between the length of the return cycle and the spontaneous cycle, using programmed premature atrial stimulation during spontaneous sinus rhythm. This approach to sinoatrial conduction assumes that sinus node automaticity is not changed by premature depolarization. In order to validate this assumption, we compared the length of the post-return cycles to the spontaneous cycle length in 71 patients. Patients were grouped according to clinical diagnosis and the value of calculated SACT. At long coupling intervals at which no reset of the sinus node occurred there was only a small prolongation of the post-return cycles (less than 8.4 msec, on an average) compared to the spontaneous cycle length. This suggests no or only an insignificant effect of premature depolarization on the sinus node. However, during test stimuli leading to reset of the sinus node, the post-return cycles were significantly prolonged between 20 to 30 msec, on an average. The response of the individual cases sometimes varied to a great extent. In patients who demonstrated a progressive linear prolongation of the return cycles at decremental shortening of the test interval, there was no significant prolongation of the post-return cycles versus the spontaneous cycle length. We conclude that 1) premature depolarization of the sinus node may have a depressant effect on sinus node automaticity, which, if present, is usually small; 2) calculation of SACT using the extrastimulus technique may overestimate true SACT.

Action Potentials↗