PubMed Health⌕ Search

Biomedical subjects

V M Alatriste

Publications and source records attributed to V M Alatriste.

At least 19 recordsLinked to original sources
PubMed1980

A search for modulation in intermittent ventricular parasystole.

As recently described by Moe et al., parasystolic modulation implies that the ectopic cycle length of a parasystolic focus can be increased or decreased by electrical influences transmitted across the zone of protection. A search for this phenomenon was made in nine patients with intermittent ventricular parasystole resulting from protection only during specific portions of the cycle. All nine patients had a period of relatively early protection affecting the initial 55-67% of the cycle preceding a period of resetting during which the parasystolic focus was discharged and fully recycled. In addition, two patients had a period of relatively late parasystolic protection. Pseudo-resetting (apparent resetting in the surface leads without interruption of activity within the parasystolic focus itself), seen throughout the entire period of late protection in these two patients, and during the relatively refractory period in one patient, was identified because the R waves causing apparent resetting were encompassed by parasystolic-to-parasystolic intervals equalling twice the ectopic cycle length. Our findings indicate that parasystolic modulation did not occur in the type of intermittent ventricular parasystole included in this study. That is, the parasystolic focus was either not affected (not modulated) during specific (early or late) portions of the cycle, or normally reset (discharged and fully recycled, but neither depressed, nor enhanced) in other portions of the cycle. This study does not exclude the occurrence of modulation in other types of parasystole, nor in some automatic nonparasystolic rhythms.

Adult↗
PubMed1978

His bundle recordings in atrioventricular nodal alternating Wenchebach periods ending in 5:1 atrioventricular block coexisting with paroxysmal atrioventricular nodal block.

Atrioventricular nodal alternating Wenckebach periods ending in 5:1 atrioventricular block occurring during rapid atrial rhythms were explained by postulating the presence of block in three levels of the atrioventricular node. This pattern of conduction occurred in ten of 11 patients who either had received ouabain or verapamil (nine patients) or who had organic atrioventricular nodal disease (two patients). In contrast, this pattern of conduction occurred in only one of eight nonmedicated patients without organic atrioventricular nodal disease. The frequent association of this pattern with paroxysmal, tachycardia-dependent atrioventtricular nodal block suggested a similar, but not necessarily identical, mechanism. In conclusion, atrioventricular nodal alternating Wenckebach periods ending in 5:1 atrioventricular block, as well as paroxysmal atrioventricular nodal block, were only rarely the result of rapid atrial rates per se their occurrence indicating organic or pharmacologic effects on the atrioventricular node. Since both can be produced by carotid sinus pressure, further studies appear to be necessary to determine the role that vagal effects can have in their genesis.

Bundle of His↗
PubMedDate not supplied

[Aerobic functional capacity in normal subjects].

The functional evaluation of a subject may be performed by measurement of the functional aerobic capacity by means of exercise-stress tests. The maximal oxygen consumption (VO2 max) is the best parameter to establish this. The values of VO2 max were determined in twenty-five normal subjects, residents of Mexico City. There were twenty men and five women whose ages ranged between the third and fourth decades of life. A maximal exercise-stress test was performed in a treadmill, with constant inclination and progressive speed increments. Electrocardiogram and blood pressure were monitorized at rest, during exercise and in the recovery period. Four collections of espired gas were obtained, one at rest and three at different levels of exercise. VO2/kg. at rest (the value of one met) was 3.49+/-0.58 ml/kg. min. for the whole group somewhat lower for males (3.37+/-0.53 ml/kg. min.) than for female subjects (3.99+/-0.51 ml/kg. min.). These results are comparable to the ones informed in the literature. VO2 max/kg. was 27.8+/-5.57 ml/kg. min. for the entire group and 28.0+/-5.64 and 27.3+/-5.94 ml/kg. min. for men and women respectively. The values of VO2 max/kg. are definitely lower than the ones obtained from normal subjects in other countries. Considerations are made on the possible causes of this discrepancy. A linear correlation was found between VO2/kg or mets in one side and load imposed, cardiac rate or double product (pulse-pressure) in the other. The different VO2 max/kg. values found in this study as compared to the results obtained from other countries, serve to emphasize the need for each laboratory to establish its own normal values and to construct nomograms for the adquate evaluation of functional aerobic capacity. This, in turn, will permit the accurate and correct prescription of exercise for individual subjects or patients.

Adult↗
PubMedDate not supplied

Cardiac and pulmonary diseases. A pathophysiologic interelationship.

Left heart diseases, in particular mitral stenosis, are often associated with anatomic and functional alterations of the lung. According to the pulmonary structures involved they could be named chronic secondary intersticial and vascular lung diseases. Congenital heart diseases with pre- or post-tricuspid shunts are also often associated with anatomic and functional alterations of the lung. This condition also constitutes a chronic secondary vascular lung disease (atrial septal defect) or a chronic primary vascular lung disease ( ventricular septal defect, patent ductus arteriosus). Primary lung diseases (interstitial pulmonary fibrosis, pulmonary emphysema, recurrent pulmonary embolism) are often associated with right ventricular hypertrophy with or without dilation, a condition commonly named chronic cor pulmonale. On the whole the interrelationships between heart and lung diseases are as follows: a) anatomic and functional alterations of the lung due to left heart diseases are mediated through pulmonary venous hypertension; b) anatomic and functional alterations of the lung due to congenital heart diseases are mediated through the increased pulmonary blood flow with or without transmission of the systemic blood pressure to the pulmonary vasculature, and c) anatomic and functional alterations of the right ventricle due to primary or secondary lung diseases are mediated through arterial pulmonary hypertension. In summary, the interrelationships between heart and lung diseases are mainly mediated through the pulmonary venous or pulmonary arterial hypertension.

Blood Pressure↗
PubMedDate not supplied

[Auricular Q wave in right precordial derivations. New sign of left auricular growth].

The authors present four cases of rheumatic heart disease with severe dilatation of the left atrium which reached the right profile in the radiologic study. An initial negative deflexion of the P-wave (qP) in the right precordial leads was recorder in these cases. The presence of qP was interpreted in view of the atrial activation and the solid angle of the right precordial leads as a variation of potential of the right atrial ceiling and/or of the high interatrial septum, a consequence of the dislocation of the right atrium produced by severe dilatation of the left atrium, demonstrated radiologically in the cases studied. Thee presence of qP is another undoubtably valuable sign for inferring a severe displacement of the left atrium toward the right profile.

Adolescent↗
PubMedDate not supplied

[Obstructive pulmonary emphysema. Evolution of various parameters of pulmonary function and its correlation].

A follow-up study was carried on in a series of 20 patients with chronic obstructive pulmonary disease. The parameters analyzed were forced expiratory volume in the first second (FEV1), maximum voluntary ventilation (MVV), forced expiratory flow (FEF), vital capacity (VC), and diffusing capacity of lung (DL). Considering the importance of the parameter changes observed, each of these parameters were divided in three groups. The period of observation was of two and a half years in 9 patients, and between two years and seven months to four years in 11 patients. The follow-up was characterized by stability of the parameters in cases with the greatest degree of changes, and a definite deterioration of the parameter values in patients with minor degree of basal changes. It was observed an excellent correlation between FEV1 and MVV and FEF. As to CV and DL, the relationship was only good. These findings lead us to believe that MVV and FEF values can be predicted about from the FEV1 results.

Carbon Dioxide↗