Enhancement of noradrenaline-induced metabolic coronary dilatation by ethanol

Effect of alcohol intoxication on hemodynamic physiology and outcome in patients with traumatic cardiac tamponade

BACKGROUND

Alcohol intoxication has a detrimental effect on hypovolemic shock. Our aim, was to study its effects on "pure" cardiac tamponade (i.e., without hypovolemia) in patients with penetrating chest injuries.

METHODS

Thirty-five intoxicated and 15 nonintoxicated patients (blood alcohol > and < 17 mmol/L) were studied. Initial vital signs (trauma scores), special investigations (hematologic profiles, blood gases, glucose, lactate, and catecholamines), clinical progress (24- and 72-hour acute physiology and chronic health evaluation II scores) and outcome were compared.

RESULTS

Intoxicated patients were older (p = 0.02) and more tachypneic on admission (p = 0.006), but no other differences were noted. Mortality was proportional to the degree of shock and was greater in patients who had "front-room" thoracotomies (p < 0.001). Despite the higher percentage of intoxicated patients who were "lifeless" or "in extremis" on admission, they fared no worse than nonintoxicated patients.

CONCLUSION

Alcohol intoxication does not have an adverse affect on traumatic cardiac tamponade.

Effect of ethanol on regional myocardial blood flow and hemodynamics, before and after coronary artery ligation in dogs

The effects on regional myocardial blood flows (RMBF) and hemodynamics due to ethanol administered before and after acute coronary artery ligation (CAL) in 18 anesthetized dogs were studied. Ethanol was administered to seven dogs (group I) prior to CAL and to six dogs (group II) after CAL; five dogs (group III, control) received only saline before and after CAL. Uniform blood ethanol levels (180 +/- 30 mg/dl) were maintained in groups I and II after initial ethanol administration. In these groups the heart rate and rate-pressure product (which reflects myocardial oxygen consumption) remained stable, but pulmonary arterial pressures were elevated. Other hemodynamic parameters remained stable in all groups. Ethanol caused a significant transmural increase of RMBF (p less than 0.001) in both groups I and II. In group II the increase was significant in both nonischemic and ischemic tissues, with no apparent redistribution of flow among the myocardial layers. The percentage increase of RMBF due to ethanol was highest in group II nonischemic tissue (95-107%) compared to the corresponding ischemic tissue (57-60%) and the group I myocardial tissue (36-47%) prior to CAL (p less than 0.001). The observed differences between ethanol pre- and posttreatments suggest different interactions between ethanol and catecholamines. The results also confirm that vasodilatory reserve is present in the acutely ischemic myocardium and that the local availability of ethanol is important for coronary vasodilatation.

The effect of ethanol on arrhythmias and myocardial necrosis in rats with coronary occlusion and reperfusion

Ethanol (1, 2 and 3 g/kg, intravenously) decreased the severity of the ischemic arrhythmias in rats with ligation of the left coronary artery and subsequent coronary reperfusion. Reperfusion arrhythmias occurring intensively after occlusion times of 5 and 15 min, respectively, were however not antagonized. Similar results were obtained in isolated perfused rat hearts with final concentrations of 4 and 6 mg ethanol/ml. In rats with reperfusion after 60 min of coronary occlusion, 2 g ethanol/kg significantly reduced the percentage of the ischemic area which underwent necrosis. Moreover, the increase in the wet weight/dry weight ratio of the lungs, as a measure of edema formation, was prevented. The ethanol effects are discussed in the light of present knowledge of the pathogenesis of arrhythmias and myocardial necrosis in experimental myocardial infarction.

The pressor and metabolic effects of alcohol in normotensive subjects

Changes in blood pressure, pulse rate, and plasma catecholamines, renin activity, cortisol, and calcium were studied in 16 normotensive subjects (eight with a family history of hypertension) for 5 hours following ingestion of alcohol-free and alcohol-loaded beer. Both systolic and diastolic blood pressure rose after alcohol consumption; maximum responses occurred at peak blood alcohol concentrations and were significantly higher than those seen after placebo. Pulse rate was also significantly higher after alcohol ingestion and continued to rise throughout the study. There was no difference in the pressor response to alcohol between the groups with and without a family history of hypertension. No difference was found in plasma norepinephrine or epinephrine levels between alcohol and placebo phases. However, subjects with no family history of hypertension had significantly higher plasma norepinephrine levels (p less than 0.01) than did those with a family history during both the alcohol and placebo phases, although baseline blood pressures were not significantly different. Plasma epinephrine level was similar in both groups. Plasma renin activity was unchanged throughout, but plasma cortisol fell during both phases. Plasma calcium showed a small but significant fall with alcohol consumption in both groups (p less than 0.001). These results indicate that in normotensive subjects alcohol ingestion causes a rise in systolic and diastolic blood pressure that is not influenced by a family history of hypertension. This effect does not appear to be sympathetically mediated but may be due to a direct vasoconstrictor effect of alcohol, possibly with an alcohol-induced shift in intracellular calcium.

Long-term effects of cigarette smoking and moderate alcohol consumption on coronary artery diameter. Mechanisms of coronary artery disease independent of atherosclerosis or thrombosis?

Epidemiologic studies have shown that cigarette smoking (increased risk) and moderate alcohol consumption (decreased risk) have opposite effects in coronary artery disease. To investigate whether they act via the common mechanism of affecting the coronary diameter, 31 white men with arteriographically normal coronary arteries were evaluated. Histories of cigarette smoking (never smoked, exsmoker, or current smoker) and alcohol consumption (nonuser or low user versus moderate users with an average of one drink per day) were analyzed for an association with coronary diameters. Nonsmokers had larger left main and left anterior descending diameters than either exsmokers or current smokers (p = 0.0001 and 0.004). Moderate alcohol users had large left main and left anterior descending diameters than nondrinkers (p = 0.009 and 0.01). Neither association was removed after adjustment for the other risk factor. These data suggest that smoking and moderate alcohol use have significant, independent, and opposite effects on long-term coronary diameter. These effects may be important mechanisms through which these behaviors alter the risk of coronary artery disease.

Enhancement of metabolic coronary vasodilatation by nicotinic acid or amide

Cardiostimulation produced by noradrenaline, glucagon, or tachycardia on the isolated perfused rat heart produced a metabolic coronary dilatation that was potentiated by nicotinic acid or its amide [NIC; 0.05-1.0 mM] without affecting the cardiostimulation. Reactive hyperaemia to brief coronary occlusion was unaffected by NIC, thus confirming that its vasodilator mechanism is of a different nature than that leading to metabolic coronary dilatation. It is suggested that NIC may be of significance as an adjuvant in the treatment of certain types of coronary insufficiencies.

Ethanol- and isoprenaline-induced responses in pig parenchymal lung tissue

Ethanol (8.7-34.8 mM; 0.5-0.20% v/v) had no significant effect on spontaneously developed tension in pig lung parenchyma strips, although higher cumulative concentrations caused relaxation (at 34.8-174 mM) and contraction (at 348-1392 mM). Ethanol-induced effects were not caused by activation of adrenoceptors or of cholinoceptors, since blockade of these receptors did not alter those effects. Single low concentrations of ethanol (8.7-34.8 mM) which can occur in-vivo in man, caused increases in the relaxant potency of isoprenaline in pig lung strips, although the sizes of these increases varied widely. In addition, ethanol-induced potentiation of isoprenaline was not concentration-related. This effect was not caused by inhibition of isoprenaline uptake since [3H]isoprenaline transport was found not to be significantly altered in the presence of ethanol (8.7-34.8 mM).