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Biomedical subjects

A Masoni

Publications and source records attributed to A Masoni.

At least 73 records · Page 4Linked to original sources
PubMed1981

[Paroxysmal supraventricular tachycardias due to re-entry via concealed retrograde atrio-His bypass (author's transl)].

Recently there have been proposed electrophysiologic criteria for the diagnosis of a concealed atrio-His bypass tract in patients with paroxysmal supraventricular tachycardia (PST). In order to verify the reliability of the proposed criteria--among the patients we studied for PST without ventricular preexcitation and in whom retrograde His bundle activation was recorded--we have chosen those with normal anterograde A-V conduction, with constant (or minimal increases) V-A interval during ventricular pacing and with short (less than 50 msec) and constant H2-A2 interval during ventricular premature stimulation. We encountered 15 patients with these electrophysiologic characteristics (37-73 years). H2-A2 interval (measured from the end of the His bundle deflection to the earliest atrial activity) ranged 20-45 msec (mean: 33 msec). The prolongation of S2-A2 interval observed in all patients was always within the S2-H2 tract. The retrograde effective refractory period of the A-V nodal region was always short, but not evaluable in any of the patients since it was shorter than that of ventricular myocardium (14 cases) or of His-Purkinje system (1 case). The S1-H2 interval was measured to evaluate whether during ventricular premature stimulation the retrograde His bundle activation was in fact anticipated. In 14 out of 15 patients this interval varied within a very narrow range: 0-20 msec. For this reason we believe that the differential diagnosis between a concealed atrio-His bypass and an accelerated retrograde A-V conduction can only be made if during electrophysiologic study a tachycardia is induced; in such case the detection of an H-Ae interval identical to H2A2, together with a normal retrograde atrial activation, is indicative of a bypass of the A-V node. A concealed atrio-His bypass tract must be differentiated also by a concealed septal Kent bundle; also in this case we believe that the detection of an H-Ae interval identical to H2-A2 indicates the former type of bypass. We conclude that a concealed atrio-His bypass can be diagnosed only if, besides the electrophysiologic criteria proposed by other authors, there is an H-Ae interval the same as H2A2.

Adult↗
PubMed1981

One year efficacy and tolerability of oxprenolol slow-release and chlorthalidone on fixed combination in mild to moderate hypertension.

The long-term antihypertensive efficacy and tolerability of a fixed combination of oxprenolol 160 mg slow-release + chlortalidone 20 mg was studied in 40 out-patients with mild to moderate essential hypertension followed during one year with monthly clinical visits. The fixed combination was given at the dosage of 1 tablet once daily, in the morning, increasing to 1 tablet b.i.d. in case of lying diastolic blood pressure greater than 95 mmHg. After one year only 9 patients were on 1 tablet b.i.d., the others remaining on 1 tablet once daily regimen. Clear-cut antihypertensive effect was already evident after the 1st month of treatment. Both systolic and diastolic blood pressure further decreased after two months (p less than 0.01) showing then a constant trend to decrease till the 6th month; afterwards blood pressure values remained unchanged. Normalization of blood pressure was obtained in 63%, 73% and 80% of the patients, respectively after 1, 6 and 12 months of treatment. Laboratory data did not show significant changes. Only 3 patients complained of unwanted effects which were mild, transient and in no case compelled to interrupt the treatment. Results confirm that the fixed combination of oxprenolol 160 mg slow-release + chlorthalidone 20 mg is able to long term control mild to moderate hypertension with a good tolerability, thus allowing an improved patient compliance.

Adult↗
PubMed1980

[The bundle branch block anatomically located in HIS bundle (author's transl)].

Bundle branch block (BBB) patterns are commonly considered to represent conduction block in the corresponding bundle branch. However, several histological and experimental studies demonstrated the possibility of a BBB related to an anatomical lesion within the His bundle. Recently there has been demonstrated, also in clinical setting, the possibility of evaluation whether a left bundle branch block (LBBB) is related to an anatomical within such bundle. For this purpose the selective stimulation of the His bundle has been utilized. A distal simulation of such bundle (which can be evaluated by a stimulus-QRS interval shorter than HV interval) normalizing the QRS complexes compresses an anatomical lesion within the proximal His bundle. Such normalization cannot be attributed to a right septum stimulation since the LBBB pattern should be increased instead of disappearing. The Authors think that an anatomical localization within the His bundle can be evaluated only in LBBB. In fact it is possible that a right bundle branch block pattern, if a septal calcification or fibrosis is present, could be normalized also in the presence of an isoelectric line placed between the artificial stimulus and the QRS complex. There is criticized the concept supported by other Authors that normalization of the QRS complex may be related to a summation effect between the sinusal impulse and that artificially induced. In fact such effect can be easy excluded by analizing the temporal relationship between the ventriculograms registered during His bundle stimulation and the atriograms. The clinical implications of the LBBBs in relation with an anatomical lesion within the His bundle are discussed.

Bundle of His↗
PubMed1979

Moulting in Rana esculenta: development of mitochondria-rich cells, morphological changes of the epithelium and sodium transport.

The present study concerns moulting of the skin in Rana esculenta in vivo and in vitro. The evolution of mitochondria-rich cells (MRC) and changes in the epithelium during moulting were followed. The greater part of the MRC are lost during moulting, either because they remain attached to the old stratum corneum or because they are left in contact with the external medium and degenerate. The cells thus lost leave deep impressions in the new stratum corneum which disappear progressively. Before an MRC is shed, a cell of the stratum intermedium contacting it differentiates to form a new MRC to replace the old. Isolation of the skin triggers moulting in the excised pieces. This moulting does not cause changes in the short-circuit current or in the transepithelial resistance. Aldosterone (10(-6) M) added in vitro to the serous side appeared to facilitate the detachment of the slough, however, no clear-cut moult-inducing effect of the hormone was seen.

Aldosterone↗
PubMed1979

Effects of dobutamine on electrophysiological properties of the specialized conduction system in man.

The electrophysiological effects of Dobutamine, a new beta adrenergic drug, were investigated using intracardiac electrograms and the extrastimulus method, in 19 patients with 1:1 AV conduction and in 10 other patients, five with second and five with third degree AV block. The electrophysiological effects were studied at three concentrations of the drug: 5, 10 and 15 micrograms/Kg/m'. Dobutamine induces: 1) an enhancement of SA node automaticity, showed by a decrease of the sinus cycle length (P less than 0.001 at the first concentration) and by a decrease in the corrected sinus node recovery time (P less than 0.001 at the second concentration); 2) a decrease in the effective atrial refractory period (P less than 0.001 at the first concentration); 3) an improvement of AV conduction, showed by a decrease in AH interval (P less than 0.001 at the first concentration) and by a shortening of functional and effective refractory periods (P less than 0.001 at the first concentration); 4) no change in the HV interval; 5) an improvement of conduction in patients with second degree AV block proximal to the His bundle; and 6) a minimal increase in the heart rate in patients with complete AV block distal to His bundle.

Adult↗
PubMed1979

2:1 and phase 4 peri-infarction block.

A patient with acute inferior and anteroseptal myocardial infarction initially developed a 2 : 1 AV block with alternate conducted ventricular complexes showing aberrancy, and later Wenckebach-type, 2nd-degree AV block with aberrancy of the beats following a long diastolic pause. Intracavitary recording suggested that aberrancy was related to an intraventricular block. ECG and VCG recordings excluded the site of block as being in the main bundles or in the fascicles of the left bundle. The patient therefore showed evidence for a 2 : 1 and later a phase 4 peripheral block, defined also as a peri-infarction block because of the underlying etiology of the block. The block could be localized in the posterior wall of the right ventricle, by the marked rightward and posterior orientation of the middle and terminal electrical forces evident in the vectorcardiogram.

Acute Disease↗
PubMed1979

[Short-term and median-term effects of tienilic acid in hypertension].

Fifty nine patients suffering from slight or moderate essential arterial hypertension underwent hypotensive treatment. After one week of wash-out, therapeutic administration of tienilic acid in doses of 500 mg per day was begun; in the third week we combined a non diuretic hypotensive drug (prazosin, propranolol, alfametil-dopa). At the beginning of the study all patients underwent an ECG, a clinical cardiological examiniation, funduscopy examination, funduscopy examination, a heart X - ray in 3 standard positions and a routine blood test which was repeated during and at the end of the treatment. The patients' blood pressure taken in an upright and supine position, showed statistically significant reductions for both systolic and diastolic values in all 3 groups, whereas the routine blood tests gave evidence of a marked reduction in the uriacid, triglycerides and potassium levels. In order to correct the latter we had to administer high oral doses of potassium, and in one case admittance to hospital was necessary since the potassium level was lower then 2.5 mEq/l.

Adult↗
PubMed1977

Left bifascicular block with normally conducting middle fascicle.

A case of aortic insufficiency showing an ECG pattern of left ventricular hypertrophy and strain has been followed over time. One year after the initial observation, the ECG and VCG recordings showed the appearance of a left bifascicular block, due to involvement of the anterior and posterior fascicles, with normal septal activation. It is suggested that the normally functioning middle fascicle activates the inferior two-thirds of the septum. This hypothesis is discussed in light of recent experimental data.

Adult↗