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Biomedical subjects

M Santini

Publications and source records attributed to M Santini.

At least 199 records · Page 11Linked to original sources
PubMed1977

[General anesthesia in patients with intraventricular conduction abnormalities (author's transl)].

This study was undertaken to assess the risk of developing complete heart block during general anesthesia in patients with bundle branch block. His bundle electrograms were recorded during sinus rhythm and after atrail pacing in 11 patients (5 LBBB, 2 RBBB, 3 RBBB and LAH, 1 RBBB and LBH) before and after administration of Pentothal 0.20 g e.v., Succinylcholine 1 mg/kg e.v., and breathing of fluothane 1%or Ethrane. Minimal effects on sinus functions and A-V node conduction was observed during anesthesia; Fluothane only increased slightly AH intervals (+11%). Both Fluothane and Ethrane effects on HV conduction was insignificant. In 9 patients HV intervals increased of 5% after Succinylcholine; 2 patients developed a complete heart block distal to his after the drug. Possible causes of the complete heart block are discussed and a direct effect of Succinylcholine is hypothesized.

Anesthesia, General↗
PubMed1976

Convergence on interneurones mediating the reciprocal Ia inhibition of motoneurones. I. Disynaptic Ia inhibition of Ia inhibitory interneurones.

Interneurones identified as mediating the disynaptic reciprocal Ia inhibition of motoneurones (referred to as "Ia inhibitory interneurones") were recorded in the lumbar spinal cord of the cat. It was revealed that the Ia inhibitory interneurones themselves receive disynaptic Ia inhibition. The muscles from which this inhibition is evoked are strictly antagonistic to those supplying their Ia excitation. Similar to the Ia inhibition in motoneurones the Ia inhibition in the Ia inhibitory interneurones is decreased when preceded by an antidromic stimulation of ventral roots. Furthermore, transmission of Ia inhibition to the Ia inhibitory interneurones is facilitated from ipsilateral and contralateral primary afferents as well as several supraspinal pathways analogous to earlier findings for the Ia inhibition of motoneurones. The pattern and control of the Ia inhibition of motoneurones and of Ia inhibitory interneurones display so striking similarities that it is suggested that identical interneurones are responsible. The conclusion thus emerges that "opposite" Ia inhibitory interneurones (i.e. interneurones monosynaptically connected to antagonistic muscles) are mutually inhibiting each other. The functional significance of this organization is discussed.

Afferent Pathways↗
PubMed1976

Convergence on interneurones mediating the reciprocal Ia inhibition of motoneurones. II. Effects from segmental flexor reflex pathways.

Interneurones identified as mediating the disynaptic reciprocal Ia inhibition of motoneurones (referred to as "Ia inhibitory interneurones") were recorded in the lumbar spinal cord of the cat. Volleys in ipsilateral and contralateral high threshold muscle afferents, cutaneous and high threshold joint afferents evoked a mixture of polysynaptic excitation and inhibition. These effects were ascribed to pathways activated by flexor reflex afferents (FRA) and in addition a specific ipsilateral low threshold cutaneous pathway. Ia inhibitory interneurones excited monosynaptically from flexor nerves received stronger net excitation by volleys in ipsilateral FRA than did extensor coupled interneurones, while the opposite pattern was seen from the contralateral FRA. These patterns are similar to those found in flexor and extensor motoneurones respectivey. The FRA inhibition in Ia inhibitory interneurones was partly mediated by "opposite" Ia inhibitory interneurones, i.e. those which are mediating the Ia inhibition of Ia inhibitory interneurones. The extent to which the FRA inhibition is transmitted by Ia inhibitory interneurones was roughly estimated by its susceptibility to recurrent depression by antidromic ventral root stimulation. The main conclusion is that most segmental pathways seem to evoke their effects in parallel to motoneurones and Ia inhibitory interneurones which are monosynaptically linked to the same muscle. The functional importance of this conclusion is discussed in a following report.

Animals↗
PubMed1976

Convergence on interneurones mediating the reciprocal Ia inhibition of motoneurones. III. Effects from supraspinal pathways.

Supraspinal effects were investigated in interneurones identified as mediating the disynaptic reciprocal Ia inhibition of motoneurones (referred to as Ia inhibitory interneurones). It was revealed that volleys in the vestibulospinal tract may evoke mono- and disynaptic EPSPs in interneurones monosynaptically excited from extensor muscles, i.e. extensor coupled Ia inhibitory interneurones. Flexor coupled interneurones instead received disynaptic inhibition. Volleys in the rubrospinal tract evoked a dominating polysynaptic excitation, usually mixed with inhibition, in flexor as well as extensor coupled interneurones. Disynaptic rubrospinal EPSPs and IPSPs were also revealed. The pyramidal tract also gives rise to a dominating polysynaptic excitation, usually mixed with inhibition, in flexor as well as extensor coupled Ia inhibitory interneurones. Rubrospinal and pyramidal volleys were shown to facilitate transmission in various segmental reflex pathways to the Ia inhibitory interneurones. A detailed comparison reveals a striking parallelism of segmental and supraspinal effects on alpha-motoneurones and Ia inhibitory interneurones connected to the same muscles. This considerably strengthens the hypothesis of an "alpha-gamma-linkage in the reciprocal inhibition".

Animals↗
PubMed1976

[On the method for determination of sinus node recovery time (author's transl)].

On the basis of personal experience of 22 patients, 11 with sick sinus node syndrome (SSNS) and 11 without, it was concluded that the seat and length of atrial stimulation has little importance for the determination of recovery time for corrected sinus node (RTCSN). The frequency of optimal stimulation seems to be 110 impulses per minute for 2 minutes, by which it generally reaches the maximum value of RTCSN. Using this method, the falsely normal RTCSN in SSNS subjects can be verified; in these cases the test should be repeated within a larger frequency scope.

Arrhythmia, Sinus↗
PubMed1976

[Modifications and control of the myocardial threshold with the Vario pacemaker EM 169 (author's transl)].

Measurements of threshold of electrical stimulation were performed in thirty patients with A-V block, at the time of implantation of the pacemaker, after 10 days, 1-2 months and 1 year. The Vario-pacemaker was used for the measurements. An increase in the stimulation threshold of about 260% was noted after 10 days and 1-2 months. One year after the implantation of the pacemaker, the myocardial threshold was about 200% of the initial value. The method is easy to perform. It is very useful to follow the myocardial threshold changes for a long period after the implantation.

Electrocardiography↗
PubMed1976

[The values and limitations of recovery time in sick sinus syndrome (author's transl)].

143 patients were examined for SNRT and thus divided: 1st group: 39 patients with indisputable clinical signs of MNS (bradycardia-tachycardia, synocopes); 2nd group: 18 patients with constant sinusal bradycardia, but without arrhythmias; 3rd group: 86 patients without any clinical signs of sisusal automatism deficit. The average SNRT results were: 2346 plus or minus 1404 msec in the 1st group; 1337 plus or minus 181 msec in the 2nd group and 1021 plus or minus 216 msec in the 3rd. Corrected SNRT gave an average result of 1315 plus or minus 1300 msec in the 1st group; 329 plus or minus 229 msec in the 2nd and 234 plus or minus 133msec in the 3rd group. The values between the average and standard deviation...

Adult↗
PubMed1976

[Familial sick sinus syndrome. Observations on three cases studied (author's transl)].

Three siblings with sick sinus syndrome (SSS) are described. In each case, electrocardiogram, Hisian electrogram and sinus node recovery time were recorded, both in basic conditions and under the effect of drugs. In two cases a permanent pacemaker uas applied. The clinical and instrumental investigations were extended to 24 out of 33 cases included in the complete genealogical tree; three cases with arrhythmias were identified (atrial and ventricular extrasystoles and atrial fibrillation). From a genetic point of view, the SSS seemed to segregate a dominant autosomic character with a lower frequency of the disease in the descendants then expected, which is probably due to their low age.

Adult↗
PubMed1976

[Hemochromatosic cardiomyopathy. Report of a case with registration of his bundle potentials and hemodynamic examination (author's transl)].

A case of idiopathic haemochromatosis in a young adult aged 23, with pre-eminent cardiac symptoms is described. The cardiac symptoms consisted of heart failure and various types of arrhythmias (atrial and ventricular tachycardia, AV block). The haemodynamic studies revealed a biventricular diastolic hypertension; the cineangiocardiography showed a diffuse hypokinesis of the left ventricle and mitral regurgitation.

Adult↗
PubMed1976

[Coronarographic and ventriculographic aspects of 76 cases of unstable angina (authors transl)].

-- Coronarographic and ventriculographic aspects of 76 patients with unstable angina were analyzed. 8 cases (10%) had normal coronary arteries, 9 (11.8%) had slight stenotic lesions (less than 50%), 59 (77.6%) had serious stenosis. The stenosis concerned only one principal branch in 22 patients (37.2%), 2 branches in 24 (40%), 3 branches in 13 (22%). In 77-79% of cases, ventricular contractility was normal. A collateral circulation was found in 58% of cases, but no link was discovered between the coronaric lesions and the clinical type of angina. The course of the illness was studied during the hospitalization and post-hospitalization period for an average observation time of 14 months (55 cases). The course of illness type depends on the number of affected branches and the myocardial contractility. In 25% of the patients with lesions in 3 branches there was an unfavourable course of illness (either infarction or death), whilst where there were lesions in one or two branches, negative results were 11% and 15% respectively. Patients with normal coronary arteries or slight stenosis had no unfavourable course of illness. In 37% of patients with altered contractility, an unfavourable course of illness was found, as against 27% with normal contractility. The presence of collateral circulation doesn't seem to influence the course the illness takes. A coronarographic examination seems to be an essential elelment in deciding on the prognosis of unstable angina.

Angina Pectoris↗