[Exercise test in young steers at 2800 M above sea level]. / Pruebas de esfuerzo en banda sin-fin en jóvenes a 2800 m SNM.

Among its different activities the Mexican Health Ministry (SSA) promotes: 1) the specification of biological standards for the Mexican population; 2) mechanisms for early detection of physiopathological changes and 3) development of the appropriate technology as a basis for primary health care. As part of this program we studied a random sample of students at the "Colegio de Bachilleres" of Cuajimalpa a suburban area of Mexico City, situated at 2800 m above sea level, part of the equipment used was produced at the Center for Development and Technological Applications (CE-DAT), an agency of SSA. Height, weight, heart rate (HR), systolic and diastolic blood pressures (SBP/DBP) were measured at rest in sitting position, standing up and walking on a treadmill. The results show a population with similar physical characteristics to those described for other populations in Mexico, with HR values within a homogeneous distribution, except for three subjects with rates larger than 2 standard deviations (SD). At standing up, women showed an orthostatic reflex of 27 beats/min and men of 22 beats/min. At the beginning of the exercise, the HR curve becomes more homogeneous, showing a discrete ascending slope with a low correlation coefficient, suggesting low physical capacity of the studied population. As exercise continued, some subjects showed a low increment of HR, giving values differing by 2 SD. Five women and three men had resting SBP values lying 2 SD out of the mean values of the sample. During exercise, SBP increases 28 mmHg as average. Notwithstanding the low cardiac response, the time spent on the treadmill lies within the levels considered as good and, even, excellent, on the table of the National Institute of Cardiology. We discuss new procedures to analyze instantaneously the HR and the pressoreceptor reflex as well as their functional significance.

Caracteristicas electrocardiograficas en embarazo a termino y postparto.Correlacion con lipidos sericos. / Electrocardiographic characteristics in pregnancy at term and postpartum.Correlation with serum lipids

En el sindrome gravidico circulatorio se incluyen ciertas caracteristicas electrocardiograficas que no tienen significado patologico y cuyo origen es aun incierto.El objetivo del estudio es el conocer la incidencia de estas caracteristicas en 51 embarazadas sanas a termino; observar cuales de ellas persisten en el puerperio inmediato, a la semana y a las cuatro semanas, y tratar de correlacionar estos hallazgos con los niveles de lipidos sericos La mayoria de estas embarazadas tienen corazon con eje electrico dirigido a la izquierda que se torna a la derecha a las cuatro semanas de puerperio.La caracteristica electrocardiografica mas frecuente es el desnivel del segmento ST en derivaciones precordiales; sin embargo, no se considera exclusivo del embarazo ya que tambien se presenta en el puerperio. Con lo que respecta a otras caracteristicas su presencia es variable. Los niveles de lipidos son elevados durante el embarazo e inmediatamente despues del parto, descienden; la titulacion a las cuatro semanas no se llevo a cabo. No se encontro correlacion entre la incidencia de las caracteristicas electrocardiograficas y los niveles de lipidos sericos

Hallazgo de onda auricular en electrocardiografia fetal externa. / Atrial wave findings in external fetal electrocardiography

Se presenta el informe de seis casos donde fue posible registrar por medio de electrocardiograma maternofetal externo, la onda P fetal u onda de activacion auricular, precediendo al QRS fetal en 11 trazos. La dificultad que ha existido en la obtencion del electrocardiograma fetal completo, ha llevado a un retrazo en el diagnostico preciso de las arritmias cardiacas fetales, de ahi la importancia de este hallazgo del que se discutem algunas interrogantes

[External fetal electrocardiograms with P wave. Report of 6 cases]. / Electrocardiograms fetales externos con onda P. Informe de seis casos.

The purpose of this report is to present six pregnancies in which by means of external fetal electrocardiography, besides the feto-maternal QRS complexes, a clear fetal P wave can be identified. The number of electrocardiograms taken per patient was of one or more. In one of the cases this finding has persisted from the 26th to the 30th weeks of pregnancy. When analyzing the clinical characteristics of the cases, the only commun finding was that each one of the pregnancies averaged between nineteen and twenty six weeks of amenorrhea. Attention is called to search for the possible reasons by which commonly the fetal P wave can not be detected. Findings of other authors are discussed.

Electrocardiogramas fetales externos con onda P. Informe de seis casos. / External fetal electrocardiograms with P wave.Report of 6 cases

Se presentan seis casos de embarazadas, en las que por medio de electrocardiografia fetal externa, se registra claramente, ademas de los QRS maternofetales, la onda P fetal.El numero de registros realizados en cada caso es variable; tal es el caso numero seis en el que este hallazgo ha persistido desde la vigesima sexta hasta la trigesima semana. Al analizar las caracteristicas de ellos, la unica comun encontrada es la edad de gestacion que esta comprendida entre 19 y 26 semanas.Los propositos de este informe son: agregar cuatro casos mas a los previamente presentados, asi como despertar el interes por indagar las posibles razones, por las que comunmente no se puede registrar la onda P fetal.Se discuten los hallazgos de algunos autores

[Exercise test and differential diagnosis of fetal arrhythmia]. / Pruebas de esfuerzo y diagnóstico diferencial de arritmias fetales.

The cases here reported show in the first place that external fetal ECG is useful to detect fetal distress and should therefore be included as a prenatal control from the second trimester of pregnancy on, specially in cases where there is a past history of fetal death of unknown origin, or a family history of congenital heart defects. A fetal tolerance test to exercise should also be done in those cases with a past history of fetal death, distress or whenever chronic fetal distress may be suspected to take place because of the presence of maternal pathology (endocrine, cardiovascular, or infectious diseases, etc.). Fetal tolerance test to uterine contractions should also be done whenever possible to evaluate the tolerance of these fetuses to uterine contractility during labor. More studies are needed to establish standard guides of this method for the practical obstetrical management of products of high risk pregnancies.