Effects of delayed recanalization of an occluded acute myocardial infarction-related artery using coronary angioplasty on late potentials

BACKGROUND

Recent evidence suggests that late reperfusion of an occluded infarct-related artery after an acute myocardial infarction may reduce the frequency of subsequent arrhythmic events. Late mechanical reperfusion by percutaneous transluminal coronary angioplasty (PTCA) under these circumstances has a high success rate. The present study was performed to test the hypothesis that the late mechanical restoration of anterograde flow in an occluded infarct artery after an acute myocardial infarction causes a resolution of late potentials.

METHODS

Twenty subjects (10 men, one woman; aged 32-77 years) suffering a first acute myocardial infarction, with signal-averaged electrocardiographic (ECG) recordings and a severely occluded infarct-related artery, were prospectively identified.

RESULTS

Eighteen patients underwent successful PTCA of the occluded artery 6-32 days after a first acute myocardial infarction. Late potentials were observed in 14 patients 5-22 days after the infarction. A follow-up signal-averaged ECG was performed 1-8 days later. In the subgroup of 12 patients with successful reperfusion and an abnormal signal-averaged ECG before PTCA, seven (58.3%) showed resolution of the late potentials at follow-up; in these patients the filtered QRS duration showed a significant reduction (112.1 +/- 14.2 to 96.7 +/- 12.7 ms, P = 0.02), the root-mean-square voltage increased (9.8 +/- 6.5 to 33.1 +/- 15.5 microV, P = 0.017), and the duration of low-amplitude signals < 40 microV decreased after angioplasty (46.3 +/- 11.0 to 28.5 +/- 6.5 ms, P < 0.022). In contrast, two patients with late potentials before PTCA and unsuccessful reperfusion had no significant changes in signal-averaged ECG.

CONCLUSIONS

In some patients with an acute myocardial infarction, late mechanical reperfusion of the culprit vessel may reduce the incidence of abnormalities on the signal-averaged ECG. Whether this will improve long-term survival has yet to be confirmed in a large trial.

[Fasting and postprandial lipids and lipoproteins during the chronic administration of antihypertensive drugs]

To evaluate the effect of various antihypertensive drugs on fasting and postprandial lipids and lipoproteins, we studied 39 normolipidemic hypertensive patients, 28 men and 11 women aged 52.3 +/- 9.0 and 58.5 +/- 7 years, respectively. After four weeks of placebo administration, lipids and lipoproteins were measured in the fasting state and every three hours for a period of nine hours after intake of a standardized fat mixed load (65 g/m2). Following this test, the patients were randomly assigned to one of four treatment groups: group I metoprolol (n = 10), 100 mg/day; group II nicardipine (n = 9), 90 mg/day; group III captopril (n = 11), 75 mg/day. At the end of week four of treatment the fasting and postprandial lipid measurements were repeated. Blood pressure mean values were significantly (p < 0.05) reduced in the four treatment groups. We found no statistically significant lipids or lipoproteins changes neither in the fasting nor in the postprandial state, but a trend toward lower concentrations in the postprandial lipemia after treatment was observed in three groups (metoprolol, nicardipine and captopril), whereas no change was observed in the chlorthalidone group. These data confirm that fasting lipids and lipoproteins in normolipidemic hypertensive patients are not unfavorably changed by low doses of the drugs studied. In addition, we inform that postprandial lipemia is not affected by these four drugs in the doses used.

Long distance runners and body-builders exhibit elevated plasma levels of lipoprotein(a)

A one-point cross-sectional study of 20 sedentary individuals, 20 low-aerobic athletes (body-builders), and 20 high-aerobic athletes (long distance, endurance runners) was conducted in Mexico City, Mexico to determine the influence of these diverse life-styles on the plasma levels of Lp(a). Only non-obese male subjects, aged 23-33, who were nonsmokers, non-alcoholics, and had never used anabolic steroids were included in this study. Blood samples were drawn 24 h following the last period of physical activity, and after a 12-14-h fast-period and a 15-min sitting-rest. Plasma levels of Lp(a) and other parameters, including postheparin lipoprotein lipase (LPL) and hepatic lipase (HL) activities, triglycerides (TG), total cholesterol (TC), LDL cholesterol (LDL-C), and HDL cholesterol (HDL-C), as well as % body fat and muscle mass, and maximum aerobic capacity (VO2max) were measured to determine possible correlations with Lp(a) and to serve as convenient internal standards. Mean Lp(a) concentrations were significantly higher in the runners (52 +/- 19 mg/dl) than in the body-builders (40 +/- 6.4 mg/dl, P < 0.05) and the sedentary subjects (24 +/- 5 mg/dl, P < 0.001). Positive correlations between Lp(a) and Vo2max (P < 0.001), HDL-C (P < 0.005) and HDL2-C subfraction (P < 0.005), and a negative correlation with TG were determined. Agglomerative cluster methods suggested three close-distance clusters and a fourth cluster which is composed of four runners who exhibited low LDL-C/HDL-C and high LPL/HL ratios, high mean Lp(a), HDL2-C, and Vo2max levels, but low TG levels. These data show that some individuals who maintain a life-style of very high level physical exertion may have remarkably elevated plasma Lp(a) concentrations. The highly increased concentrations of Lp(a) in high exercise athletes may represent a normal metabolic response to repeated small tissue injuries resulting from frequent and prolonged large muscle movement.

[Serological survey of human leptospirosis in a high risk population in Chile]

Two hundred and sixty five subjects with high risk works for leptospirosis were submitted to microscopic agglutination test for leptospira. 122 worked at animal farms, 71 in rice growing fields and 72 in slaughter houses. 30 control subjects were also tested. A total of 66 samples (22%) were positive, most of them with low titers. Percentage of positive reactions were higher for persons working in rice fields, followed by those working in slaughter houses and animal farms. The 21-40 year age group was most affected in all working sites. Serovars found most commonly were ichterohemorrhagic in rice field workers, hardjo and ballum in slaughter houses and pomona and hardjo in animal farms.

[Peritoneal dialysis in the newborn (author's transl)]

In the period 1972-1978, forty peritoneal dialysis were performed in thirty seven newborn infants. Their weights were comprised between 1,250 and 5,600 gr., being under 2,000 gr. in eight cases. Peritoneal dialysis was considered as a therapeutic method integrated on the whole treatment approche applied to each critically ill newborn. Its indication was due to renal failure in twenty seven cases and to severe water and electrolyte disturbances in ten cases. Except for one newborn infant with a likely lactic acidosis, our aims in setting an adequate blood depuration and maintenacne of the water and electrolye balance were attained. In two cases we could correlate an aggravation of the clinical state with final death to complications partially due to the procedure. Other incidents in relation with peritoneal dialysis were less relevant and did not interfere with the clinical course followd by the patients. In our experience, peritoneal dialysis was a simple and highly useful method in the treatment of neonates with renal failure or severe metabolic disturbances.

Whole-blood fibrinolytic activity in normal and hypertensive pregnancies and its relation to the placental concentration of urokinase inhibitor

Whole-blood fibrinolytic activity was measured in 68 pregnant and 29 nonpregnant women with a sensitive, solid-state assay in which 125I-labeled fibrin was bound to polystyrene tubes. Antepartum fibrinolytic activity in 36 normotensive gravid women [234.5 +/- 29.2 (mean +/- standard error of the mean) ng fibrin lysed/30 min] was significantly (p less than 0.001) greater than that found in 28 nonpregnant normotensive women not taking oral contraceptives (63.61 +/- 7.66 ng fibrin lysed/30 min) and not different from the activity observed during the active phase of labor (198.50 +/- 16.5 ng fibrin lysed/30 min.) Normotensive pregnant patients had a significant (p less than 0.001) increase in whole-blood fibrinolytic activity (341.04 +/- 25.7 ng fibrin lysed/30 min) within the first 24 hours after delivery which persisted in measurements taken the second postpartum day. Fibrinolytic activity values before labor, in the active phase of labor, and in the first and second postpartum days in 17 patients with mild to moderate pregnancy-induced or pregd or pregnancy-aggravated hypertension were not different from those found in the normotensive group. However, patients with severe pregnancy-induced or pregnancy-aggravated hypertension had significantly (p less than 0.01) lower levels of fibrinolytic activity than normotensive patients before labor, during the active phase of labor, and on the first and second postpartum days. The placental 800 X g and 110,000 X g fractions of patients with severe hypertension had a significantly (p less than 0.001) greater capacity to inhibit "in vitro" urokinase-induced fibrinolysis than similar fractions obtained from placentas of normotensive women, and there was a significant inverse correlation (r = 0.61; p less than 0.01) between whole-blood fibrinolytic activity and urokinase inhibition by placental fractions. Our findings indicate that contrary to widely held views, fibrinolysis is extremely active in term pregnancies and during labor and that a derangement of this activity is present in cases of severe pregnancy-induced or pregnancy-aggravated hypertension.