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Biomedical subjects

G A Medrano

Publications and source records attributed to G A Medrano.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

[Electrocardiographic changes in 29 apparently healthy subjects with positive serological tests for Chagas disease].

Of 78 apparently healthy subjects with positive serological tests for Chagas disease, 29 had EKG abnormalities. On direct questioning only two referred dyspnea, one had palpitations and another one dizziness. The most frequent EKG abnormalities were: peaked T waves in 10 cases; ventricular premature beats in 8 patients, right bundle branch block in 7, left bundle branch block in 5, abnormal ST-T segment in 4, atrial fibrillation in 3 cases, left ventricular hypertrophy in 3, and left anterior hemiblock in 3. As has been previously recognized, the EKG changes plus the positive serological tests are the earliest manifestations of Chagas disease.

Adolescent↗
PubMedDate not supplied

[Myocardial ischemia in hypertension heart disease (author's transl)].

Seventeen hypertensive patients with EKG evidence of left ventricular hypertrophy and subendocardial ischemia were studied. The following tests were performed: cine-ventriculography, coronary arteriography, ejection fraction, ventricular pressures, left ventricular mass, EKG stress test and atrial stimulation. In 10 cases cardiac scintigraphy with intracoronary injection of albumin-macro-aggregates marked with TC 99m, was obtained. EKG stress and atrial stimulation tests were positive in all cases, with ST depression greater than 1mm, or accentuation of previous ST depression. 83.7% of the patients had permeable coronary arteries, with "corkscrew' tortuosity. Left ventricular mass was increased in all cases (119 +/- 28.5% m2 s/c). Ejection fraction (74.2 +/- 8.1), and left ventricular diastolic pressures were normal. Cardiac scintigraphy showed uniform distribution of the radioisotope in the right ventricle and poor concentration with better dispersion and distribution in the left ventricle. It is concluded that subendocardial ischemia in these subjects is not produced by obstruction of the main coronary trunks and is associated to a significant increment of left ventricular mass which possibly produce a poor coronary reserve, and a potentially high risk condition.

Adult↗
PubMedDate not supplied

[Apical hypertrophic myocardiopathy. Report of the first case identified on the American continent].

What appears to be the first case of hypertrophic apical myocardiography described in the western hemisphere is presented in this report. The diagnosis was confirmed by angiocardiography and echocardiography. The electrocardiogram showed the characteristic giant T waves. It is of interest that the coronary radioangiography suggested alterations in the microcirculation which could explain the striking electrocardiographic pattern of subepicardial ischemia seen in these patients.

Adult↗
PubMedDate not supplied

[Electro-vectorcardiogram in myocardial infarct with involvement of the right ventricle in humans].

The electrocardiograms of 7 patients with anatomical diagnosis of right ventricular infarction, were studied. Electrocardiographic and vectorcardiographic records of 11 patients surviving the acute stage of myocardial infarction, were also analized. In 10 cases, both ventricles were involved. All patients had echocardiograms, ventriculograms and cineangiograms of coronary arteries, which showed the damaged vessels and the severity of their alterations. A severe obstrucción of the right coronary artery was found in all the cases, except one, in each group. The signs of necrosis were recognized in DIII, aVF, right unipolar thoracic leads and abdominal leads MD, ME, less frequently MI. They consisted in QS, Qr or W complexes in the absence of intraventricular blocks, and in slurred QR complexes in the cases with right proximal or distal blocks. Q wave duration fluctuated between 35 and 60 msec. The orientation of the initial vectors resulting from the ventricular activation sequence (20 - 40 msec) as well as ARST were different if obtained from usual precordial loads or the right thoracic ones. The latter was concordant with the orientation observed in the standard leads. VCGF suggested the posterior-inferior necrosis by its clockwise rotation and delayed downward crossing (32.5 - 50 msec) or by the situation of the entire ventricular curve above and to the left of E point. The duration of QF loop as increased in 9 (17.5 - 35 msec) Analysis of VCGH made possible the diagnosis of anterior septal necrotic zone because of the changes in QH loop. VCGS generally started upward and showed a delayed crossing of the anterior-posterior axis downward.

Heart Ventricles↗
PubMedDate not supplied

[Electrical changes in experimental diastolic and mixed overloads of the right ventricle].

The paper describes the electrical changes in 115 mongrel dogs with exposed heart and open pericardium, during the gradual development of diastolic and combined (diastolic and systolic) overloading of the right ventricle. Ventricular overload was produced by means of a constant venous infusion of saline solution: up to 12 liters in 3 hours and half. In all cases, right intraventricular conduction disturbances, of either proximal or distal type, appeared. Right blocks were classified on the base of the topography of the ventricular activation delay. They were correlated with the hemodynamic adaptation. The results of this study allow us to formulate the following main points: 1) Disturbances of the right intraventricular conduction during experimental diastolic and combined overloading of the ipsilateral ventricle, seem to be due to a distention of the ventricular specialized fibers; 2) proximal right blocks are related to a global dilatation of the ventricular chamber, secondary either to a quick overloading or to a decrease in the myocardial capacity for adaptation; 3) distal right blocks are caused more frequently by a distention of the anterolateral portions of the free right ventricular wall, where the right middle subdivision is located.

Animals↗
PubMedDate not supplied

[The electrocardiogram of the normal child].

The EKG findings of 202 normal children, aged 1 month to 10 years were reviewed in order to determine criteria for diagnosis of ventricular hypertrophy. QRS voltage in right and left precordial leads are very variable and do not constitute adequate criteria for the diagnosis of ventricular hypertrophy the same is true with QRS duration, which increases progressively from 50 to 60 msec from the first to the fourth year of life, and to 70 msec over that age. The values found are smaller than those previously reported in the literature. Measurement of initial intrinsicoid deflection time in leads VI, aVF and V6 apparently have important clinical significance. This is a constant finding in normal hearts in lead VI, where deflection time is 18 to 20 msec. Therefore, times above 25 to 30 msec are sugestive of right ventricular hypertrophy when RBBB is not present. Intrinsicoid deflection time in lead V6 in children under one year of age was 20 msec, while between age one and ten it varied between 20 and 31 msec. Such variations show how left ventricular tissue increases after the first years of life, and also that times above 5 msec over those found for any age group are indicative of left ventricular hypertrophy.

Age Factors↗
PubMedDate not supplied

[Disorders of the right intraventricular conduction in chronic pulmonary hypertensive cardiopathy].

Disorders of the right intraventricular conduction were analyzed in cases of chronic pulmonary hypertensive cardiopathy (C.P.H.C.), diagnosed on basis of the anatomic data. The series studied here (40 cases) was obtained from the review of 3,000 reports of autopsies at the Instituto Nacional de Cardiología de México. Thickness of the free right ventricular wall, thickness of the interventricular septum at three levels, thickness of Wolf's spur and the circumference of the 4 valvular rings, were determined in each heart. Haemodynamic studies and respiratory function tests were revised in those cases in which they had been practiced. Electrocardiographic study essentially analyzes the time of onset of intrinsicoid deflection as well as the morphology of ventricular complexes in the unipolar leads. In 37 cases (92.5%), a disturbance of the right intraventricular conduction was present. R.B.B.B. was observed in 29 cases (72.5%): 12 of minor degree, 19 of intermediate and 1 of advanced degree. Right peripheral block was diagnosed in 8 cases (20%): anterior type in 2 cases (5%); posterior type in 6 cases (15%). In the cases with R.B.B.B., the anatomic data of right ventricular hypertrophy were predominant; in those with R.A.S.B., anatomical data suggested right ventricular enlargement. The facts exposed here permit the following conclusions: 1) Diagnosis of right fascicular block can be suggested even in the presence of hypertrophy of the corresponding ventricle. 2) Hypertrophy of the right ventricle appears more directly related to the homolateral bundle branch block than to distal or segmentary blocks. 3) Topographic diagnosis of delay in the right ventricle activation process can be established by an electrocardiographic thoracic mapping that permits to explore the ventricular structures at different levels.

Adolescent↗