[Insulin resistance: an etiological factor in essential arterial hypertension and coronary cardiopathy]. / Resistencia a la insulina: factor etiológico de la hipertensión arterial esencial y de la cardiopatía coronaria.

Insulin resistance has been implicated in the pathogenesis of essential hypertension. Studies from other countries discovered insulin resistance; in people with essential hypertension in was also associated with obesity, however, insulin resistance was found in lean people too. In obesity, insulin resistance occurs secondarily to many physiopathological states and circulating factors which adversely affects insulin action. The metabolic abnormality in this action was mainly found in relation to abdominal fat; in other cases, insulin resistance was found to be inherited. Hyperinsulinaemia can actually increase blood pressure and is associated with venous and arterial thrombosis and it also rises lipid levels. It is interesting too that insulin resistance and hyperinsulinaemia are associated with impaired fibrinolysis through high levels of fibrinogen and plasminogen activator inhibitor of endothelial type and in identifying individuals prone to myocardial infarction. Some antihypertensive drugs like beta-blockers, methyl-dopa and diuretics increase insulin resistance, while angiotensin converting enzyme-inhibitors have not shown any adverse metabolic affects. Alfa-1-blocker were beneficial and alfa-2-agonists were neutral, whereas calcium channel-antagonists are still in controversy. Treatment should be designed to improve the metabolic state; physical exercise, a diet rich in fruit, vegetable and rott vegetables, the reduction of abdominal fat and, finally, the use of antihypertensive drugs which decrease insulin resistance would be expected to reverse hyperinsulinaemia. Biguanides like metformin have also been found to reduce insulin resistance.

[The prevention of postinfarction left ventricular dilatation by captopril]. / Prevención de la dilatación del ventrículo izquierdo postinfarto del miocardio por captopril.

Thirty patients admitted to the ICCU with a first myocardial infarction (MI) of any localization, with left ventricular dysfunction revealed by echo-Doppler ejection fraction (EF) < 40%, where randomly divided in three groups of ten: GROUP 1 who was treated with captopril 25 mg orally between the 5th and 7th day post MI, and sustained until the end of the study. GROUP 2 received nifedipine, 10 mg capsules t.i.d. also started between days 5 and 7 post MI. GROUP 3 as a control group was treated conventionally, according to the ICCU routine. The treatment was maintained during 12 months. All patients had a second echo-Doppler at the 5th day post MI to confirm the EF criteria. Also left ventricular end-systolic and end-diastolic diameters were measured. At the 5th day post MI and before the drug administration, a low level treadmill stress test was performed in all patients. Subsequently a maximal stress test (Bruce protocol) was done at the first month and at 6 and 12 months of the study. The results showed a significant increase EF in patients of GROUP 1 from an average basal value of 38 +/- 2 to 54 +/- 5 at six months (p < 0.01) and to 60 +/- 3 at 12 months (p < 0.005). The increments observed in patients of GROUP 2 and 3 were more modest; only the 12 month value in GROUP 3, from a basal figure of 41 +/- 3 to 50 +/- 4, had a p < 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

[Prognostic value of the exercise test in patients with ischemic heart disease]. / Valor pronóstico de la prueba de esfuerzo en pacientes con cardiopatía isquémica.

The objective of this study is to determine the prognostic value of stress testing in patients with coronary heart disease. We examined 95 cases followed during an average period of 33 months. The age was 52 +/- 9 years. All patients had clinical evidence of myocardial ischemia: 78 had previous myocardial infarction, 11 stable angor pectoris and six unstable angina. After the initial event 33 patients were asymptomatic and 62 with mild angina. During follow-up; 42 patients had no coronary events; 10 died, six developed non-fatal myocardial infarction and 37 had more angina, nine of these patients were treated with bypass coronary artery surgery. The annual mortality was 3.8%, all with previous myocardial infarction. In the stress testing the patients who died were distinguished by limited exercise ability and severe changes of ST-T segment. Patients with greater than or equal to 0.2 mV ST-T segment depth or effort duration less than or equal to 3 minutes had an annual mortality F 7% 13.6% respectively.

[Phonomechanocardiographic analysis in patients with artifical pacemaker]. / Análisis fonomecanocardiográfico en pacientes con marcapaso artificial

Eighteen patients with artificial pacemakers have been studied by phonomecanocardiographic means. All had complete atrio-ventricular block. Ten had an endocardial electrode in the right ventricle and 10 an epicardial in the free wall of the left ventricle. Two patients were studied, first with a temporal endocardial pacemaker and then with a permanent one. The studies were divided in 3 groups: Group I. In six cases comparison was made between the systolic tunes of the normally conducted cycles, and the ones produced by direct ventricular stimulations. The beats produced by direct ventricular stimulation showed a statistically significant diminution of the function of the left ventricle. This was reflected by a shorter relative ejection period. This diminution can possibly be explained by one of two mechanisms: absence of the "atrial kick", or alteration in the sequence of depolarization and ventricular contraction, producing an asynchrony in the contraction. This would lead us to suppose that the best site for contact of the electrode would be the middle third of the left aspect of the ventricular septum, where the activation starts normally. Group II. Ventricular function was compared in 20 cases, depending on the site of electrical stimulation: endocardium of right ventricle or epicardium of the left ventricle: there were no statistically significant differences. Group III. On 14 cases we studied cycles in which an effective contribution of the atrial kick could be expected, because the interval between the P wave and the electrical artifact was less than 300 msec. These were compared with others with a larger, statistically significant, improvement of the left ventricular function it was observed as a longer ejection period in the cases with a P wave-electrical artifact pause shorter than 300 msec.