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Biomedical subjects

F Loogen

Publications and source records attributed to F Loogen.

At least 163 records · Page 9Linked to original sources
PubMed1976

The effect of atropine on calculated sinoatrial conduction time in man.

This study investigates the effect of atropine on the length of the return cycles after premature atrial stimulation in man. On the assumption that sinus node automaticity is not changed by premature depolarization of the sinus node, sinoatrial conduction time (SACT) was calculated from the differences between the length of the return cycles and the spontaneous cycle length. 11 patients were studied before and after the injection of atropine. In all cases atropine caused an increase in heart rate. In 8 patients the return cycles exhibited a typical behavior. In 6 patients without signs of sinus node dysfunction, the mean calculated SACT was 109 msec, whereas 2 patients with a sick sinus syndrome (SSS) had a mean calculated SACT of 190 and 225 msec, respectively. 3 patients with SSS demonstrated an atypical pattern of the postextrasystolic pauses. In 6 patients without sinus node dysfunction, atropine caused a reduction of calculated SACT about 35%. In 2 patients with SSS the reduction was 38 and 49% of the control value, respectively, whereas in the remaining 3 patients with SSS who had an atypical return cycle pattern, a normalization occurred after the administration of atropine. We conclude that, besides its effects on sinus node automaticity, atropine has also a marked effect on sinoatrial conduction, even in patients with the sick sinus syndrome.

Arrhythmia, Sinus↗
PubMed1976

[Course observations of hypertrophic obstructive myocardiopathy].

The course of HOCM is characterized by a slow progression. Symptoms can often be influenced favourably by medical treatment. Altogether there is some difference between the course of untreated and the propranolol-treated patient groups which is, however, not statistically significant. Furthermore, the rate of sudden death is uninfluenced. Comparing clinical and haemodynamic results in medicically treated patients we find a reduction of the outflow tract obstruction in case with clinical improvement but not a reduction of the enddiastolic pressure. Independent on the clinical course there was a significant increase of the enddiastolic pressure after 5.5 years. We may conclude that there is a progredient process of hypertrophy which is uninfluenced by the obstruction and by conservative management. The best results are obtained in the operated group. According to our results a surgical intervention should possibly be considereed more generously.

Adolescent↗
PubMed1975

[Clinical value of His bundle electrography (author's transl)].

Methodical problems, indication and clinical implication of His bundle electrography are discussed. In 200 successive patients undergoing His bundle electrography and atrial stimulation the indication was as follows: Intraventricular conduction defects in 24%, A-V block in 21%, sick sinus syndrome in 20%, preexcitation in 17%, and complex arrhythmias in the remaining cases. In 38% of the patients did the HBE prove to be of help by providing information not available after analysis of the surface ECG. In 22% this technique contributed essentially to the management of these patients. In spite of dificiencies of our knowledge of the basic mechanisms, specific therapy, and prognosis of various arrhythmias His bundle electrography is clinically useful in selected patients. Therefore, this method has become a routinely used clinical tool.

Arrhythmias, Cardiac↗
PubMed1975

[Diagnostic and prognostic value of endomyocardial biopsy in patients with congestive cardiomyopathy (author's transl)]rdiomyopathy(author.

Endomyocardial biopsies were obtained from the right ventricle in 25 patients with the clinical diagnosis of congestive cardiomyopathy. The biopsies were subjected to virological and histological studies (light and electronmicroscopy) and the findings correlated with clinical data. Abnormal morphological findings were present in all patients. The presumed clinical diagnosis was confirmed in 19, the morphological changes not being consistent with the clinical diagnosis of CCM in six patients. Electronmicroscopy revealed cardiac storage disease in one patient and pathological changes secondary to previous myocarditis in the other five. Clinical follow-up studies of the five patients apparently confirmed the morphological results, because in no case was there clinical deterioration, three patients in fact being in a fairly normal cardiac state at present. Using a morphological scoring system, the 19 patients with morphologically confirmed diagnosis of CCM were subdivided into two groupds, those with four points or less (group I, n equal to 9), and those with five pints or more (group II, n equal to 10). During a mean follow-up period of nearly 12 months the first group had a low mortality rate (n equal to 2), while the other had a high one (n equal to 6). The occurrence of signs of degeneration and mitochondrial alterations, in particular, was associated with a poor clinical prognosis. This differentiation into two groupds could not be achieved by clinical means alone. Type B3 Coxsackie virus was isolated from one biopsy, but no patient had significant serological evidence of virological infection.

Adult↗
PubMed1975

A new method for automated detection of the R-on-T phenomenon.

The detection of premature ectopic beats coinciding with the T-wave of the antecedent beat is important for patient monitoring. In the method described here, the difficulties of direct measurement of QT time are avoided by evaluating the changes of QT time according to heart rate by use of a diode function generator. An analog circuit is used for comparing the computed QT time with the coupling interval of successive beats. In case of a R-on-T-phenomenon an alarm is given. The frequency of alarms is registered on a trend recorder. The methods is based on empirical equations which all contain a constant factor. Our investigations showed that the variability of this factor during longer periods of monitoring was small enough to allow sufficient exactness of the evaluation procedure.

Adult↗
PubMed1975

[Letal rate and late complications following palliative surgery of transposition of the great arteria (author's transl)].

Between 1966 and 1973 145 palliative procedures were carried out on 110 infants with transposition of the great arteries. There were 23 early deaths (20.9 per cent). 85 per cent of the survivors were controlled till the end of 1974. Five late deaths and four cases of peripheral artery embolism were regarded. These complications, however, took place several years after palliation. The development of pulmonary hypertension doesn't seem to be as high as it is suspected sometimes. These results justify our conception, not to perform the Mustard-operation during the first two years of life.

Age Factors↗
PubMed1975

[Indication for coronary surgery with special reference to hemodynamic results].

An analysis is made whether and how far the aims of coronary artery bypass surgery improvement or relief of angina, improvement of the physical working capacity, improvement of the oxygen supply of ischemic myocardium, improvement of the myocardial function, improvement of longevity, can be attained. 48 percent of 87 patients had complete subsidance of angina pectoris after operation. There was a considerable improvement in 32 percent, no change in 14 percent, and a deterioration in 6 percent. After operation, the working capacity was improved in 73 percent of our patients significantly, in some cases nearly unlimited. By a comparison between loss of complaints and bypass function (open or closed) we found a good correlation between functioning bypasses and complaints. But there are some cases without complaints in spite of a closure of the bypass. Also the reverse, unchanged complaints in spite of an open bypass, was seen. A normalisation of preoperative disturbed myocardial function can be attained. Significant improvements, but also deteriorations can be found. Generally, there is a good correlation between improved myocardial function and improvement of the working capacity. Yet there is not rarely a discrepancy between a significant improvement of the working capacity and the left ventricular function. The explanation may be a loss or a postoperative augmented threshold for anging pectoris. Comparing the groups of patients with conservative and surgical treatment, the superiority of surgical treatment cannot be proved as yet. An exception seems to be the stenosis of the left main coronary artery. With this exception, prognostic considerations cannot play a role for the indication of a coronary bypass operation. Aspects for the indication of coronary surgery are untractable or disabling angina pectoris and the consideration how impending complications can be prevented.

Angina Pectoris↗
PubMed1975

[Diagnostic problems in the sinus node syndrome].

The sick sinus syndrome includes numerous arrhythmias due to various functional disorders of the sinus node, the atria and the A-V junctional tissue. These disturbances of impulse formation and conduction involve many diagnostic problems. If clinical methods as ECG monitoring are of no help, provocative tests are indicated. The best indirect test of the sinus node activity is the measurement of the sinus node recovery time after overdrive suppression. In addition, the sinu-atrial conduction time, the conduction velocity within the right atrium, the A-V node and the His-Purkinje system can be measured. In patients with the sick sinus syndrome abnormalities of conduction in the specialized cardiac tissue are common in addition to sinus node dysfunction. The results of the provocative tests are important for drug therapy or pacemaker implantation.

Arrhythmias, Cardiac↗
PubMed1975

[Atrioventricular conduction in the Lown-Ganong-Levine syndrome].

In 18 patients with LGL-syndrome His bundle electrography and atrial pacing were performed. In all cases the atrial conduction time was normal, the H-V interval within the lower limit (36 msec). The A-H interval was significantly shortened (58 msec). During rapid atrial pacing four different patterns of reaction could be distinguished: 1) A-H interval unchanged (1 case). 2) Sudden prolongation of the A-H interval at a critical rate (4 cases). 3) Continuous prolongation of the A-H time according to the driving frequency (9 cases). 4) Marked delay and block (4 cases). Verapamil had only little or no effect on the A-H interval in these patients. The results indicate, that only in a few cases with LGL-syndrome the shortened A-H time is due to a James bundle bypassing completely the A-V node.

Adolescent↗