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Biomedical subjects

G A Medrano

Publications and source records attributed to G A Medrano.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

[Cardiac involvement in ankylosing spondylitis].

Ankylosing spondylitis is a rheumatic disease that affects the axial skeleton and has predilection for young men. Of its extraarticular manifestations, the cardiac involvement, reported up to 48%, has been pointed out in recent years. It seems to exist a racial variation in the features of the spondylitis and since most of the studies have been performed in northern countries therefore it appears inadequate to extrapolate the conclusions of such studies to our society. We studied 23 patients with definitive diagnosis of ankylosing spondylitis. All of them had a complete physical examination, electrocardiography and X-ray of the chest; eight patients underwent a Holter study of 24 hours and seven patients were examined by echocardiography. The mean age of the group was 36 years; there were 21 men and two women. The mean duration of the rheumatic disease was 11.5 years. In only 4 (17.4%) of the patients we found cardiac involvement that would not be related to another etiology. By the clinic examination we found two patients with isolated aortic insufficiency; one case had a right bundle branch block. The Holter study did not show modifications, except in the one with isolated aortic insufficiency and right bundle branch block, in whom this block became of variable degree. The echocardiographic study showed the mentioned aortic valvular lesions and did reveal the same lesion in another patient in which the other studies were normal. It is emphasized that it is adequate to search for signs of ankylosing spondylitis in every patient with isolated aortic insufficiency or/and conduction disturbances of unknown etiology and also to performe cardiac careful in each patient with ankylosing spondylitis examination.

Aortic Valve Insufficiency↗
PubMedDate not supplied

[Electric signs of experimental pericarditis].

Utilizing 25 mongrel dogs, we studied the electrocardiographic (direct and surface records) and lesional changes induced by the instillation of 7.5% Methyl-salicilate solution and by the acute pericardial effusion produced by the injection of 50 ml of mixed blood-saline solution. Ten unipolar records on the parietal pericardium, right atrium, right and left intraventricular unipolar leads and cavitary tensional curves were obtained. Light and electronic microscopy changes were analized in 11 cases. The anatomical data showed pericardial hemorrhage and injury of 3 to 6 lines of superficial myocytes. On ECG (direct and surface leads) an elevation of RST-T was observed from chest and pericardial unipolar leads and depressed ST in the chambers of the heart, and from a VR and a VL. RST-T displacement as well as developing negative T waves were outstanding on the rigth chest leads (V5R to V3R), on the left (V4-to V6), in DII, DIII, aVF and abdominal leads. A straight RST-T elevation with notch at the juntional point was observed, suggesting atrial injury. No alteration of intrinsic or intrinsicoid velocity were apparent. All of these signs, together with depressed ST in leads aVR and unipolar right chamber leads are signs which suggest pericardial involvement. The P wave became bimodal on the middle chest leads and +/- on right chest leads indicating atrial damage (68%). Thus, an RST-T upward displacement in V3R-V4R, can be a sign of pericarditis as well as right ventricular infarction. The pressure curves were altered only by artificial acute effusion: RA = 20.6, pericardial sac 20.6 and late diastolic of RV = 13.2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

[Electro-vectorcardiographic aspects of diastolic and mixed overloads of the right ventricle].

We studied 400 cases of isolated atrial septal defect without severe pulmonary hypertension, in which the diagnosis was established by the hemodynamic data and it was proven by surgical findings in 257 instances. High fidelity unipolar thoracic and intracardiac records, as well as vectorcardiographic curves in three planes, were obtained. Different types of right ventricular conduction disturbances, which were present in all cases, as well as certain electro-vectorcardiographic aspects related to ventricular depolarization and repolarization, were analyzed. Mean angles of the resulting vectors at 60 msc of the ventricular activation, were determined relating to the types of block. The following points should be emphasized: Besides the right proximal blocks, which are more frequent, right distal ones can also be diagnosed by the presence of slurred R wave and delayed onset of the intrinsicoid deflection in only some right leads. The monofascicular and parietal right blocks are observed when the diastolic overload of the ipsilateral ventricle is low. The activation time of the anterior inferior right septal mass generally permits an objective classification of the degree of a right proximal block. The prolonged Q-Tc interval only in right leads, seems to be a function of the magnitude of the right ventricular diastolic overload.

Adolescent↗
PubMedDate not supplied

[Diagnosis of an inactivable myocardial zone in the presence of left intraventricular block].

The electro-vectorcardiographic manifestations of uncomplicated and complicated proximal and peripheral blocks of the left conduction system are described. In the presence of an advanced degree LBBB, the septal activation which occurs with abnormal spreading, originates electromotive forces of greater duration and consequently more importance than normal ones. Peripheral left blocks provoke a segmental delay of left ventricle activation, producing an asynchronism of the electrical phenomenon between upper and lower regions of the ipsilateral ventricle. The coexistence of an inactivable anteroseptal zone with an advanced LBBB causes the phenomenon of "wave jumping" to begin in inferior posteroseptal regions. Therefore, the left external electrodes see the first ventricular activation fronts moving away and register Q waves. The presence of a transmural inactivable left parietal zone permits the corresponding external electrodes to record the morphology of the ipsilateral intraventricular complex. In certain cases, a LASB which shifts the first septal vector downward, can mask the existence of an inactivable anteroseptal or posteroinferior zone. A LPSB, which produces a strong III l vector oriented downward and to the left, can reduce the electrical manifestation of an inactivable posteroinferior zone.

Electrocardiography↗
PubMedDate not supplied

[Diagnosis of the myocardial inactivatable zone in the presence of right and bilateral intraventricular blocks].

The electro-vectorcardiographic manifestations of uncomplicated and complicated proximal and peripheral right conduction system blocks are described. In the presence of an advanced degree right bundle branch block (RBBB), the septal activation, which occurs with abnormal spreading, originates electromotive forces of greater duration and consequently of more importance than normal ones. Peripheral right blocks provoke a segmentary delay of right ventricle activation, producing asynchronism of the electrical phenomenon between upper and lower regions of the ipsilateral ventricle. The coexistence of an inactivatable anteroseptal zone with an advanced degree RBBB cause the phenomenon of "wave jumping" to begin in inferior posteroseptal regions. Therefore, the transitional leads see the first fronts of the said phenomenon moving away and register Q waves. The presence of a transmural inactivatable right parietal zone permits the corresponding external electrodes to record the morphology of the ipsilateral intraventricular complex. In certain cases a right anterior subdivision block (RASB) or a right posterior subdivision block (RPSB) can complicate with an inactivatable septal or ipsilateral septo-parietal zone, but these do not notably modify Q waves of the ventricular complex in the right leads.

Electrocardiography↗
PubMedDate not supplied

[Vectorcardiogram in experimental infarct of the right posterior ventricular wall].

In 20 dogs a chemical necrosis was produced by infiltration of 80% phenol solution within the posterior right ventricular wall and the neighboring interventricular septum. Vectorcardiographic loops were obtained by the cube system in vertical and horizontal heart positions under control conditions, 90 minutes after the necrosis was produced and also after RBB was severed. In 15 dogs the RBB was injured after the necrosis was produced and in 5 previously. In all dogs direct unipolar leads (epicardial and intraventricular), thoracic and abdominal unipolar leads (MD, ME, MI) as well as standard leads were also obtained following the experimental protocol outlined above. Analysis of the changes caused by necrosis in the location rotation and voltage of the initial, intermediate and preterminal portions of the vectorcardiographic curve in the three planes (F, H and left S) permits the formulation of the following conclusions: 1) The most significant alterations were observed in the frontal and sagital planes, particularly in RF and RS loops. In most of the cases, RF and RS loops were displaced upwardly, to the left on the frontal view and slightly anterior on the sagital. The rotation changed to counterclockwise direction on the frontal view and to clockwise on the sagittal one. In a few cases, the clockwise rotation of RF loop was conserved but it was displaced above the mean value of RF curl in horizontal hearts (+ 3 degrees 30'). 2. RH loop shifted posteriorly in both vertical and horizontal heart positions. The area enclosed by centripetal anterior branch RH loop was reduced and its apex was frequently delayed by 3 msec. 3) In presence of RBBB, the alterations described above on the frontal and sagittal views were conserved in both heart positions. The only distinct behaviour was observed in the horizontal loop, in which RH loop is posteriorly located with counterclockwise rotation in the vertical hearts and anteriorly in the horizontal one. Nevertheless, the voltage of R loops increased in both positions when the necrosis was produced after the RBBB. 4) In spite of differences in thickness of the right ventricular wall between dog and man (it is thicker in the dog), we propose that alterations of RF and RS loops could be extrapolated to the human V.C.G. in order to evaluate the involvement of the right ventricle by myocardial necrosis. 5) Similar alterations of RF and RS loops were observed in the presence of necrosis of the left posterior ventricular wall. The only clue to establish a differential diagnosis is based on the characteristics of RH loop, which is more anteriorly displaced with an "8" aspect or clockwise rotation in the presence of left side necrosis. Both VCG and ECG appear to be helpful on the topographic diagnosis and evaluation of injured myocardium in the right ventricle.

Animals↗
PubMedDate not supplied

[About vectorcardiographic examination].

The clinical importance of the spatial exploration of the cardiac electrical phenomenon (vectorcardiography), which is a very useful integration of the analytical and limited electrical exploration (electrocardiography), is outlined here. Reasons inducing the mexican school to prefer the Grishman's cube method for the vectorcardiographic recordings of other more elaborate and complex systems, are explained. The former reflects in a more reliable way the sequence of myocardial depolarization and repolarization. Morphological and chronological aspects characteristic of the normal vectorcardiogram in the frontal, horizontal and sagittal planes, are described. Additionally some typical examples corresponding to the three main electrical heart positions are presented. The vertical position is frequent in children and longilineal persons, the intermediate position is common in adults and the horizontal one is observed in age people and brevilineal persons. Some vectorcardiographic aspects typical of myocardial necrosis, injury and ischemia are discussed, underlining the importance of the complementary elements given by vectorcardiography.

Female↗