Risk factors related to the occurrence of silent myocardial ischemia in Mexicans.

BACKGROUND: Silent myocardial ischemia is a growing world health problem. It has been related to factors that promote an increase in myocardial oxygen demand or affect coronary vasomotor tone. Coronary artery disease has shown an increasing trend in Mexico in this century. HYPOTHESIS: The aim of the study was to estimate the strength of the association between some risk factors and the occurrence of silent myocardial ischemia. METHODS: A cross-sectional study was conducted and 249 individuals were screened by 24-h Holter electrocardiogram. Silent myocardial ischemia was diagnosed in patients with painless transient ST-segment depression. All subjects were interviewed for coronary risk factors and total serum cholesterol was measured. RESULTS: Silent ischemia was diagnosed in 115 patients (46%), who were older (59 +/- 9 vs. 57 +/- 11 years; p = 0.01). In a logistic regression analysis, a lower risk for silent ischemia was found in patients with thrombolysis [odds ratio (OR) 0.28; 95% confidence interval (CI 95%) 0.14-0.53], or those who followed their medical treatment (OR 0.16; CI 95% 0.04-0.68). The major risk factors were hypercholesterolemia (OR 1.6; CI 95% 0.9-2.9) and more severe coronary artery disease (OR 2.5; CI 95% 1.1-5.7). CONCLUSIONS: Some coronary risk factors are related to silent ischemia. It is still important to diagnose this entity, but modification of its related risk factors should be kept in mind to diminish its occurrence and its severe consequences.

[Hormone profile of the essential hypertension patient with ischemic cardiopathy. I. Renin, angiotensin and aldosterone]. / El perfil hormonal del hipertenso esencial con cardiopatía isquémica. (I) Renina, angiotensina y aldosterona.

To evaluate the characteristics that the renin and aldosterone profile could present in essential hypertensive patients complicated with ischemic heart disease, and as a contribution to the knowledge of the roll that these hormones could have as possible "risk factors" of coronary heart disease, sixty male patients were studied. These were divided in three groups: group I, formed by 15 essential hypertensive patients with objectively demonstrated ischemic heart disease; group II integrated by 15 essential hypertensives with no ischemic heart disease and group III with 30 normal volunteers. Serum levels of plasma renin activity (PRA) and aldosterone determined by radioimmunoassay, and of urinary sodium excretion were measured in all the patients. The distribution of cases with high, normal and low renin and aldosterone were similar in group I and in group II. It was interesting to find that the four patients of group I who were non-smokers, presented the lower renin levels (from 0.36 to 2.8 ng/ml/h). The relation between PRA and the number of occluded coronary arteries revealed an increased number of patients and affected arteries in the subgroup with renin levels above 5 ng/ml/h in comparison with the subgroup with PRA from 0 to 5, although the difference was not statistically significant. By our study, we cannot conclude that the PRA and aldosterone behave in a different fashion in essential hypertensives from those complicated with ischemic heart disease.

[Permanent pacemakers: 15 years' experience]. / Marcapasos definitivos: experiencia de quince años.

We report a 15 year experience in the attention of patients with definitive pacemakers. This study includes 200 patients treated from 1964 to 1978, with an age range from 15 to 102 years, who required 329 generators. The predominant cardiopathy was atheroesclerotic (172 cases). We analyze the associated diseases in which hypertension was prominent in 30% of these cases. The most frequent rhythm alteration was atrioventricular block in 72% of the cases, and trifascicular block in 16%. We observed 35 intercurrent complications (17.5%), and the most frequent was infection of the generator bag. Mortality in these patients averaged 11%, being strictly imputable to the pacemaker in only 2%. Eighty patients needed generator change and we report a case who required up to six changes. The implantation of permanent pacemakers for treatment of patients with severe arrhythmias is considered at present secure and effective.

Marcapasos definitivos: experiencia de quince anos / Definitive pacemakers: a 15 years' experience

Se informa la experiencia de quince anos, en la atencion de pacientes con marcapasos definitivos. El estudio incluye 200 pacientes, tratados en el lapso de 1964 a 1978, con edades entre 15 y 102 anos, que requirieron 329 generadores. El tipo de cardiopatia predominante fue la ateroesclerosa con 172 casos. Se analizan las enfermedades asociadas destacando la hipertension arterial sistemica en el 30% de los casos. El trastorno del ritmo con mayor frecuencia determinante de la indicacion de colocar un marcapaso fue el bloqueo auriculoventricular (72% de los casos), seguido del bloqueo trifascicular en el 16%. Se observaron 35 complicaciones (17.5%), de las cuales la mas frecuente fue la infeccion de la bolsa del generador. El promedio de mortalidad en estos pacientes fue del 11%, siendo en forma estricta imputable al marcapaso solo el 2%. Ochenta pacientes necesitaron cambios de generador e informamos un caso que requirio hasta 6 cambios. La implantacion de marcapasos permanentes para el tratamiento de pacientes con arritmias graves se considera en la actualidad seguro y efectivo, permitiendo una mejoria en la duracion y calidad de vida