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An analysis of health research in Chile is made, considering factors like exaggerated professional training during undergraduate studies and clinical residencies, and displacement of professionals from academic activities to more remunerative positions. Additionally, the limited role of the Ministry of Health in research promotion, evidenced by the almost absent participation of public hospitals in clinical research is discussed. Research investment, among a 0.6 to 0.8% of the GNP, is far from developed countries and Chile has not defined relevant health problems where a search effort would have an impact in public health. The marked centralism of the country attempts against regional application to financed projects. The following suggestions are made: to increase the financing for investigation, to reassign resources allowing the access of regional institutions, to financing, to discuss in the Chilean Association of Medical Faculties (ASOFAMECH) the creation of an academic degree by means of a thesis during the professional studies and to give facilities to develop research during clinical residencies. Also, the Ministry of Health should be involved, creating a national agenda or research priorities and increasing its association with Universities. Also training programs for professionals with a special interest in investigation should be devised.

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BACKGROUND: There is not much evidence about the usefulness of digoxin or enalapril in the treatment of heart failure due to mitral insufficiency. AIM: To compare digoxin and enalapril in the treatment of heart failure due to mitral insufficiency. PATIENTS AND METHODS: Patients with mitral insufficiency, in sinus rhythm, with a heart failure grade II or III and with echocardiographic left ventricular dilatation were eligible for the study. They received sequentially, during 12 weeks each, digoxin 0.25 mg/day or enalapril in doses up to 20 mg/day, with a washout in-between period of 2 weeks. The order of the sequence was determined randomly. At the start and end of treatment, functional class according to NYHA and maximal exercise tolerance in the treadmill were assessed and a color Doppler echocardiogram was done to measure ventricular dimensions, function and degree of mitral insufficiency. RESULTS: Nine patients on enalapril and 12 on digoxin improved their functional capacity. Digoxin improved exercise time in 76 +/- 168 sec (p = 0.022), whereas this change was not significant with enalapril (38 +/- 158 sec; p = 0.2). With enalapril treatment, ventricular diastolic dimension decreased from 59.3 +/- 8.1 to 58 +/- 9.3 mm and the area of mitral insufficiency decreased from 8.1 +/- 3.5 to 6.6 +/- 3.1 cm2. Digoxin did not induce any significant echocardiographic change. CONCLUSIONS: In these patients, digoxin and enalapril improved functional class. Digoxin improved exercise time and enalapril reduced ventricular dimensions and mitral insufficiency.

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BACKGROUND: Chilean aboriginal populations (Mapuche) predominantly live in the region of Araucanía, in the southern part of the country. Their cardiovascular risk factors have not been systematically assessed. AIM: To study the prevalence of cardiovascular risk factors in the Mapuche population. SUBJECTS AND METHODS: Blood pressure, weight, height, dietary habits, fasting serum total cholesterol, HDL cholesterol and triglycerides were measured in 1.948 adults living in 28 Mapuche communities. RESULTS: Thirteen percent of males and 16% of females had high blood pressure. Body mass index was 25.5 kg/m2 in males and 28.1 kg/m2 in females. Forty five percent of women and 24% of men were classified as obese. Mean serum total cholesterol was 186.7 +/- 9.6 mg/dl, HDL cholesterol was 58.7 +/- 30.7 mg/dl, total cholesterol/HDL cholesterol was 3.4 +/- 2 and triglycerides were 155.2 +/- 91.2 mg/dl. Twenty eight percent of males and 9.6% of females smoked. CONCLUSIONS: Mapuche individuals have higher levels of HDL cholesterol a better total cholesterol/HDL cholesterol ratio and lower frequency of smoking than non aboriginal Chileans subjects.

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The benefits of digoxin in patients with atrial fibrillation may be reduced due to its limited effect on atrioventricular conduction. The aim of this work was to compare digoxin and atenolol on functional class, resting and exercise heart rate and exercise capacity in patients with atrial fibrillation. Thirteen subjects with this condition, normal echocardiographic left ventricular function and size, a resting heart rate less than 80 beats/min and with no contraindication for beta blocker or digoxin use were studied. Patients were randomly assigned to receive initially digoxin 0.25 mg o.d. or atenolol 100 mg o.d. in a double blind fashion. The doses were adjusted to obtain a heart rate between 60 and 80 beats/min at the end of the first week of treatment. After two weeks of treatment, outcomes were assessed, patients were left without treatment for one week and crossed over to the other drug after that. Resting heart rates achieved with digoxin and atenolol were similar (67 +/- 11 and 65 +/- 23 beats/min respectively). However, maximal exercise heart rates and maximal exercise time were higher during digoxin treatment (166 +/- 23 vs 135 +/- 27 beats/min and 9.95 +/- 1.68 vs 8.5 +/- 2 min respectively). NYHA functional class deteriorated in three patients receiving atenolol. We conclude that atenolol achieves a better control of heart rate during exercise but also reduces maximal exercise capacity.

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Due to differences in treatment effect in studies on the effectiveness of digoxin in patients with congestive heart failure in sinus rhythm, a cross-over placebo-controlled, randomized double blind clinical trial was performed. Thirty one patients, without previous treatment with digoxin, in New York Heart Association (NYHA) functional class II to IV, with a dilated left ventricle and/or ventricular systolic dysfunction were included. Patients received digoxin, adjusted for blood levels, or placebo, during an 8 week period, prior to crossing over to the other treatment for another 8 weeks. The order of treatments was randomly allocated. Outcome measurement were performed at the end of each 8 week period. Digoxin, compared with placebo, improved NYHA class, 6.9% vs 41.4% (p = 0.013) and increased the treadmill exercise time, 406 +/- 204 s vs 484 +/- 185 s (p = 0.003). During the digoxin treatment the left ventricular and systolic diameter was reduced from 52.9 +/- 8.9 to 50.1 +/- 9.7 mm (p = 0.016) and the shortening fraction increased from 21.4 +/- 8.3 to 24.8 +/- 8.1% (p = 0.009). No significant difference was observed in the left ventricular end diastolic diameter (LVED) of the left ventricle and in a estimation of quality of life. In conclusion, digoxin treatment produced a significant improvement in functional capacity, exercise time, and left ventricular performance.

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OBJECTIVE: To determine the prognosis in patients with diphtherial myocarditis and bradyarrhythmias and to assess the results of ventricular pacing in those with third degree atrioventricular block. DESIGN: Case series. SETTING: Referral department of cardiology in a teaching hospital. PATIENTS: Twenty four out of 46 patients admitted with diphtherial myocarditis over 10 years had bradyarrhythmias. Six had sinus bradycardia, 15 atrioventricular or intraventricular conduction disturbances, and three atrioventricular dissociation. MAIN OUTCOME MEASURE: Death rate. RESULTS: Eleven patients died (46%): all seven patients with third degree atrioventricular block, the patient with bifascicular block, and three of the six patients with bundle branch block. Seven died of cardiogenic shock and four of ventricular fibrillation. All nine patients with sinus bradycardia or atrioventricular dissociation survived. CONCLUSION: Conduction system disturbances in patients with diphtherial myocarditis are markers of severe myocardial damage and a poor prognosis. In addition, ventricular pacing does not improve survival.

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A random sample of 200 males from 25 to 64 years of age was surveyed for cardiovascular risk factors in Temuco, a city in Southern Chile. Blood pressure was 130 +/- 18/85 +/- 10 mmHg and total cholesterol was 193 +/- 50 mg/dl. 33% were smokers (mean of 8.2 cigarettes per day) and 34% were ex smokers. Prevalence of hypertension was 6.5% from 35 to 44 years of age, 15% from 45 to 54 and 31.9% from 55 to 64 (mean 15%). Cholesterol levels above 240 mg/dl were found in 11.8, 18.3 and 19.1%, respectively (mean 15.5%). Half of the hypertensive subjects were not aware of their high blood pressure and only 16.6% received therapy.

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A group of 102 patients (66 males, age 62 +/- 11 years) surviving an acute myocardial infarction was followed for 6 to 48 months. Survival was analyzed by the method of Kaplan Meier and Cox analysis was used to identify prognostic factors. Thirteen patients died during follow up: 3 had sudden death, 3 a stroke, 3 died from heart failure, 3 had reinfarction and cardiogenic shock and 1 died from cholangitis. Most deaths occurred in the first few months of follow up. Survival was 92% at 6 months, 90% at 1 year, 88% at 2 years and 86% at 3 years after infarction. Single variable analysis disclosed a 2 to 3 fold late mortality risk associated to the presence of age over 60 years, old myocardial infarction, hypertension, diabetes mellitus and ventricular tachycardia or fibrillation during the acute phase. Greater than 3 fold risk was seen for patients developing heart failure or shock during myocardial infarction. Heart failure was the only statistically significant risk factor identified by multivariate analysis.

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The clinical outcome of 52 consecutive patients with hypertrophic cardiomyopathy who developed paroxysmal (less than 1 week) or established (greater than or equal to 1 week) atrial fibrillation between 1960 and 1985 was examined retrospectively and compared with that of a matched group of patients with hypertrophic cardiomyopathy and sinus rhythm. Follow-up study until death or the present ranged from 6 months to 24 years (median 11 years) from diagnosis and from 6 months to 22 years (median 7 years) from the onset of atrial fibrillation. Atrial fibrillation was present in 6 patients at the time of diagnosis, whereas it developed subsequently in 46. The acute onset of arrhythmia was associated with a change in symptoms in 41 (89%) of the 46. After initial treatment of acute atrial fibrillation, sinus rhythm was restored in 29 (63%) of the 46 patients; 43 (93%) of the 46 returned to their original symptom class. Stepwise logistic regression revealed that shorter duration of arrhythmia and amiodarone therapy were the most powerful predictors of return to sinus rhythm. Sinus rhythm was maintained during a median follow-up period of 5.5 years in 22 of the 29 patients in whom it was restored after initial therapy. During follow-up study, 25 of the 52 patients were treated with conventional therapy alone and 7 with amiodarone alone. Amiodarone therapy was associated with maintenance of sinus rhythm, fewer alterations in drug therapy, fewer embolic episodes and fewer attempted direct current cardioversions (during a shorter follow-up period).(ABSTRACT TRUNCATED AT 250 WORDS)

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The relationship between reciprocal ST-segment depression, the result of an early submaximal exercise ECG, and the anatomy of coronary artery disease was explored in 142 patients with acute myocardial infarction. Reciprocal ST-segment depression was observed in 65 per cent of 79 patients with inferior infarction and 57 per cent of 63 with anterior infarction. Thirty-three of the 52 patients with reciprocal ST-segment depression had a significant stenosis of the coronary artery supplying the reciprocal ST-segment territory (63 per cent), and 31 of the 46 patients with a positive exercise test had a significant stenosis of the coronary artery supplying the ischaemic territory (67 per cent). Forty-one of the patients with reciprocal ST-segment depression (79 per cent) and 35 of the patients with positive exercise tests (76 per cent) were found to have multivessel coronary artery disease. The study showed that reciprocal ST-segment depression was associated with stenosis of the coronary artery supplying the territory opposite the infarct in nearly two-thirds of the patients and with multivessel coronary artery disease in almost four-fifths of them. Reciprocal ST-segment depression after infarction was as accurate as a positive submaximal exercise test at predicting the presence of multivessel coronary artery disease.

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Con el fin de evaluar la importancia de la contracción auricular en pacientes (pac.) con Marcapaso (MP) ventricular en pacientes con Insuficiencia Cardíaca (IC), se efectuó cateterismo cardíaco derecho y medición de Presión Arterial (PA) directa en 11 pac. con bloqueo a-v total y MP: 4 pac. sin IC y 7 con IC. Se efectuó medición de presiones y débito (DC): 1.- Basal (B); 2.- Con estimulación auricular secuencial (ES) con estimulador externo Medtronic 5325 y 3.- Con estimulación auricular intra QRS (EI). El DC. B. de 3.86 ñ 0.30 lt/min. aumentó a 4.53 ñ0.48 lt/min., con 17.3% de incremento en relación a DC.B (p< 0.0025). Con EI. el DC. bajó a 3.60 ñ 0.14 lt/min. que es 6.7% inferior a DC.B y 20.5% inferior a ES. (p.< 0.01). En los pacientes con IC. el aumento del DC con ES fue de 0.36 ñ 0.4 lt./min. (8% mayor que DC.B.), significativamente menor que el aumento de los pacientes sin IC.: 0.93 ñ 0.4 lt/min. que equivale a 23% (p <0.025). Al pasar de ES a EI la PA. descendió en promedio de 171/78 a 149/75 mm. de Hg. La PA. diferencial descendió 47% en los pac. sin IC y 15% en los pac. con IC., (diferencia significativa: p < 0.005). Hubo correlación lineal entre el cambio de presión y cambio de débito. Se concluye que la relación temporal P-QRS determina importantes cambios de DC y PA. Los pac. con IC tuvieron menor mejoría con ES, explicable en la IC avanzada en porción horizontal de curva de función ventricular. Ello y la amplia variación individual, justifican la metódica de estudio seguida antes de un implante de M.P. Secuencial

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In 76 patients with angiographically proven coronary heart disease and in 34 without angiographically demonstrable changes in the coronary vessels, magnesium concentration in serum was measured. The results were compared with the coronary angiographic findings, the left ventricular pump function and the known risk factors. The patients with coronary disease had on average lower magnesium values in serum than the control group (0.835 +/- 0.075 compared with 0.89 +/- 0.08 mmol/l, P less than 0.002). Separation of the coronary patients according to ventricular function showed that only patients with reduced left ventricular function (ejection fraction less than or equal to 55%) had low serum magnesium concentrations when compared with the control group (0.79 +/- 0.075 compared with 0.89 +/- 0.08 mmol/l, P less than 0.001). Patients with coronary disease and normal left ventricular function (ejection fraction greater than 55%) did not differ significantly in their magnesium concentration from the normal controls. The results show that in patients with coronary heart disease lowered serum magnesium concentrations are generally only found when left ventricular function is reduced. The high incidence of sudden cardiac death could be connected with the increased occurrence of low magnesium values in serum of patients with coronary heart disease and diminished ventricular function.

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This investigation was undertaken to determine whether the left ventricular (LV) end-systolic pressure and end-systolic volume, as measured under clinical conditions, are linearly correlated and whether the slope of the end-systolic pressure-volume relationship (P-Ves) is a meaningful parameter in the assessment of left ventricular function. The studies were performed in twelve patients (eleven with coronary artery disease and one with congestive cardiomyopathy) during which autonomic reflex responses were minimized by propranolol (0.15 mg/kg i.v.) and atropine (1 mg i.v.). Three left ventricular angiograms (at rest, after 10 mg isosorbide dinitrate and during an infusion of 2 mg/min methoxamine) were obtained from which the three respective P-Ves data points were calculated and subjected to linear regression analysis (r greater than or equal to 0.96). The slope k of the linear P-Ves relation correlated most closely with the resting ejection fraction (EF) as an exponential function (r = 0.94). The end-systolic pressure could be interchanged with the peak systolic pressure which is more easily obtained. The theoretical end-systolic volume at end-systolic pressure = 0 (V0) was not related to the resting ejection fraction. Post-extrasystolic potentiation, resulting in an acute inotropic incrementation, shifted the P-Ves toward similar volumes and steepened its slope.

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The linearity and sensitivity of the end-systolic pressure-volume (P-Ves) relation to the inotropic state of the left ventricle were investigated in 11 patients with coronary heart disease and one patient with congestive cardiomyopathy. To minimize autonomic reflex responses, propranolol, 0.15 mg/kg, and atropine, 1 mg, were administered i.v. at the beginning of the study. Three ventriculograms were performed: at rest, after oral isosorbide dinitrate, 10 mg (systolic pressure decrease greater than or equal to 15 mm Hg), and during infusion of methoxamine, 2 mg/min (systolic pressure increase greater than or equal to 10 mm Hg). The three points of the Pv-Ves relation showed linearity (r greater than or equal to 0.96). The relation between the slope k of the P-Ves relation and the left ventricular ejection fraction at rest was best described by an exponential function (r = 0.94). The use of peak systolic pressure instead of end-systolic pressure showed equally good results. The intercept of the P-Ves line on the abscissa, which represents the theoretical end-systolic volume at zero pressure, was not related to the ejection fraction under control conditions. The P-Ves relation in postextrasystolic beats was displaced toward the left (smaller end-systolic volumes) and became steeper.

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