Acute effects of alcohol and food intake on cardiac performance

The Influence of Food Intake and Preload Augmentation on Cardiac Functional Parameters: A Study Using Both Cardiac Magnetic Resonance and Echocardiography

(1) Background: To investigate how food intake and preload augmentation affect the cardiac output (CO) and volumes of the left ventricle (LV) and right ventricle (RV) assessed using cardiac magnetic resonance (CMR) and trans-thoracic echocardiography (TTE). (2) Methods: Eighty-two subjects with (n = 40) and without (n = 42) cardiac disease were assessed using both CMR and TTE immediately before and after a fast infusion of 2 L isotonic saline. Half of the population had a meal during saline infusion (food/fluid), and the other half were kept fasting (fasting/fluid). We analyzed end-diastolic (EDV) and end-systolic (ESV) volumes and feature tracking (FT) using CMR, LV global longitudinal strain (GLS), and RV longitudinal strain (LS) using TTE. (3) Results: CO assessed using CMR increased significantly in both groups, and the increase was significantly higher in the food/fluid group: LV-CO (ΔLV-CO: +2.6 ± 1.3 vs. +0.7 ± 1.0 p < 0.001), followed by increased heart rate (HR) (ΔHR: +12 ± 8 vs. +1 ± 6 p < 0.001). LV and RV achieved increased stroke volume (SV) through different mechanisms. For the LV, through increased contractility, increased LV-EDV, decreased LV-ESV, increased LV-FT, and GLS were observed. For the RV, increased volumes, increased RV-EDV, increased RV-ESV, and at least for the fasting/fluid group, unchanged RV-FT and RV-LS were reported. (4) Conclusions: Preload augmentation and food intake have a significant impact on hemodynamic and cardiac functional parameters. This advocates for standardized recommendations regarding oral intake of fluid and food before cardiac assessment, for example, TTE, CMR, and right heart catheterization. We also demonstrate different approaches for the LV and RV to increase SV: for the LV by increased contractility, and for the RV by volume expansion.

Differential modulation by vascular nitric oxide synthases of the ethanol-evoked hypotension and autonomic dysfunction in female rats

We recently reported that chronic exposure to ethanol lowers blood pressure (BP) via altering cardiac contractility and autonomic control in female rats. In this investigation we conducted pharmacological and molecular studies to elucidate the role of constitutive and inducible nitric oxide synthase (NOS) in these hemodynamic effects of ethanol. Changes caused by selective inhibition of eNOS [N(5)-(1-iminoethyl)-l-ornithine; l-NIO], nNOS (N(ω)-propyl-l-arginine; NPLA), or iNOS (1400W) in BP, heart rate (HR), myocardial contractility index (dP/dt(max)), and power spectral indices of hemodynamic variability were evaluated in telemetered female rats receiving ethanol (5%, w/v) or control liquid diet for 8 weeks. Ethanol increased plasma nitrite/nitrate (NOx) and enhanced the phosphorylation of eNOS and nNOS, but not iNOS, in the tail artery. Ethanol also reduced BP, +dP/dt(max), low-frequency bands of interbeat intervals (IBI(LF), 0.25-0.75 Hz) and IBI(LF/HF) ratio while high-frequency bands (IBI(HF), 0.75-3 Hz) were increased, suggesting parasympathetic overactivity. l-NIO (20 mg/kg i.p.) caused greater increases in BP in control than in ethanol-fed rats but elicited similar reductions in IBI(LF/HF) and +dP/dt(max) both groups. NPLA (1 mg/kg i.p.) caused minimal effects in control rats but exacerbated the reductions in BP, +dP/dt(max), and IBI(LF/HF) in ethanol-fed rats. No hemodynamic modifications were caused by 1400W (5 mg/kg i.p.) in either rat group. Together, these findings suggest that nNOS acts tonically to offset the detrimental cardiovascular actions of ethanol in female rats, and the enhanced vascular NO bioavailability may explain the blunted l-NIO evoked pressor response in ethanol-fed rats.

Upregulation of cardiac NOS due to endotoxemia and vagal overactivity contributes to the hypotensive effect of chronic ethanol in female rats

We previously reported that chronic ethanol lowers blood pressure in female rats. In this study, hemodynamic, biochemical, and immunoblot analyses were performed to investigate: (i) the roles of cardiac contractility and autonomic activity in the hypotensive action of ethanol, and (ii) whether endotoxemia-induced upregulation of cardiac and/or vascular nitric oxide synthase (NOS) isoforms underlies the hypotensive and cardiac effects of ethanol. Telemetric monitoring of blood pressure, heart rate, and myocardial contractility (dP/dt(max)) was performed in female rats receiving liquid diet with or without ethanol (5% w/v, 13weeks). Autonomic control was assessed by frequency domain analysis of interbeat intervals (IBI) and systolic blood pressure (SBP). Compared with pair-fed controls, ethanol caused sustained reductions in blood pressure, heart rate, and+dP/dt(max). Ethanol feeding increased the spectral power of high-frequency band (IBI(HF), 0.75-3Hz) and decreased the low-frequency band (IBI(LF), 0.25-0.75Hz) and IBI(LF/HF) ratio, suggesting increased cardiac parasympathetic dominance. In contrast, vascular tone was not affected by ethanol because SBP spectral bands and plasma norepinephrine remained unchanged. Myocardial expressions of eNOS and its upstream regulators, phosphatidylinositol 3-kinase (PI3K) and Akt, and plasma endotoxin and nitrite/nitrate were increased by ethanol. Myocardial iNOS was also increased by ethanol whereas nNOS remained unchanged and aortic levels of all NOS isoforms were not altered by ethanol. These findings suggest that facilitation of myocardial PI3K/Akt/eNOS and iNOS pathways, due possibly to ethanol-induced endotoxemia and/or increased cardiac parasympathetic dominance, might constitute a cellular mechanism for the reduced myocardial contractility and hypotension caused by ethanol in female rats.

Facilitation of myocardial PI3K/Akt/nNOS signaling contributes to ethanol-evoked hypotension in female rats

BACKGROUND

The mechanism by which ethanol reduces cardiac output (CO) and blood pressure (BP) in female rats remains unclear. We tested the hypothesis that enhancement of myocardial phosphatidylinositol 3-kinase (PI3K)/Akt signaling and related neuronal nitric oxide synthase (nNOS) and/or endothelial nitric oxide synthase (eNOS) activity constitutes a cellular mechanism for the hemodynamic effects of ethanol.

METHODS

We measured the level of phosphorylated eNOS (p-eNOS) and p-nNOS in the myocardium of ethanol (1 g/kg intragastric, i.g.) treated female rats along with hemodynamic responses [BP, CO, stroke volume, (SV), total peripheral resistance, (TPR)], and myocardial nitrate/nitrite levels (NOx) levels. Further, we investigated the effect of selective pharmacological inhibition of nNOS with N(omega)-propyl-l-arginine (NPLA) or eNOS with N(5)-(1-iminoethyl)-l-ornithine (l-NIO) on cellular, hemodynamic, and biochemical effects of ethanol. The effects of PI3K inhibition by wortmannin on the cardiovascular actions of ethanol and myocardial Akt phosphorylation were also investigated.

RESULTS

The hemodynamic effects of ethanol (reductions in BP, CO, and SV) were associated with significant increases in myocardial NOx and myocardial p-nNOS and p-Akt expressions while myocardial p-eNOS remained unchanged. Prior nNOS inhibition by NPLA (2.5 or 12.5 microg/kg) attenuated hemodynamic effects of ethanol and abrogated associated increases in myocardial NOx and cardiac p-nNOS contents. The hemodynamic effects of ethanol and increases in myocardial p-Akt phosphorylation were reduced by wortmannin (15 microg/kg). On the other hand, although eNOS inhibition by l-NIO (4 or 20 mg/kg) in a dose-dependent manner attenuated ethanol-evoked hypotension, the concomitant reductions in CO and SV remained unaltered. Also, selective eNOS inhibition uncovered dramatic increases in TPR in response to ethanol, which appeared to have offset the reduction in CO. Neither NPLA nor l-NIO altered plasma ethanol levels.

CONCLUSIONS

These findings implicate the myocardial PI3K/Akt/nNOS signaling in the reductions in BP and CO produced by ethanol in female rats.

Effects of short-term high-fat, high-energy diet on hepatic and myocardial triglyceride content in healthy men

CONTEXT

An association has been suggested between elevated plasma nonesterified fatty acid (NEFA) levels, myocardial triglyceride (TG) accumulation, and myocardial function.

OBJECTIVE

Our objective was to investigate the effects of an elevation of plasma NEFA by a high-fat, high-energy (HFHE) diet on hepatic and myocardial TG accumulation, and on myocardial function.

DESIGN

There were 15 healthy males (mean +/- sd age: 25.0 +/- 6.6 yr) subjected to a 3-d HFHE diet consisting of their regular diet, supplemented with 800 ml cream (280 g fat) every day.

METHODS

(1)H-magnetic resonance spectroscopy was performed for assessing hepatic and myocardial TGs. Furthermore, left ventricular function was assessed using magnetic resonance imaging.

RESULTS

The HFHE diet increased hepatic TGs compared with baseline (from 2.01 +/- 1.79 to 4.26 +/- 2.78%; P = 0.001) in parallel to plasma TGs and NEFA. Myocardial TGs did not change (0.38 +/- 0.18 vs. 0.40 +/- 0.12%; P = 0.7). The HFHE diet did not change myocardial systolic function. Diastolic function, assessed by dividing the maximum flow across the mitral valve of the early diastolic filling phase by the maximum flow of the atrial contraction (E/A ratio), decreased compared with baseline (from 2.11 +/- 0.39 to 1.89 +/- 0.33; P = 0.031). This difference was no longer significant after adjustment for heart rate (P = 0.12).

CONCLUSIONS

Short-term HFHE diet in healthy males results in major increases in plasma TG and NEFA concentrations and hepatic TGs, whereas it does not influence myocardial TGs or myocardial function. These observations indicate differential, tissue-specific partitioning of TGs and/or fatty acids among nonadipose organs during HFHE diet.

Effects of cocaine and alcohol alone and in combination on cardiovascular performance in dogs

BACKGROUND

With the proliferation of cocaine abuse, increased incidence of catastrophic cardiovascular events such as angina pectoris, myocardial infarction, ventricular arrhythmias, or sudden death are reported. Many of these patients also drink alcohol before and after cocaine use, leading to a high frequency of simultaneous exposure to both the drugs. Cocaine and ethanol's independent effects on cardiodynamics are well documented, but their combined effects on complete cardiovascular hemodynamics remain unknown. Are effects additive, synergistic, or antagonistic?

METHODS

Sixteen dogs were instrumented to pass cardiac catheters into right and left ventricles. After they recovered from the effects of anesthesia, experiments were performed. In phase I, 18 experiments (6 dogs) established the dose by dose response curve. In phase II and III, another 10 dogs, subjected to 30 experiments, were given i.v. cocaine followed by ethanol and vice versa to study their effects on hemodynamics and coronary flow reserve.

RESULTS

Phase I: doses of cocaine (2 mg/kg) and ethanol (400 mg/kg) were established. Phase II: cocaine increased heart rate, blood pressure and dP/dt but ethanol administered after cocaine attenuated these effects [first derivative of the left ventricular pressure (dP/dt) < 2052 +/- 104 from 2614 +/- 110 mm Hg/sec; P < 0.04)]. Phase III: alcohol mildly increased hemodynamic parameters. Cocaine's administration as the second drug had synergistic excitatory effects (dP/dt > 3300 +/- 160 from 2854 +/- 142 mm Hg/sec; P < 0.004).

CONCLUSION

Cocaine increased heart rate, blood pressure, and dP/dt but reduced CFR. Alcohol mildly increased the hemodynamic variables and CFR. Combined cocaine and alcohol attenuated the excitatory effects of cocaine significantly. A reversed drug combination (ie, alcohol then cocaine) generated synergistic excitatory effects on the cardiovascular system of the dogs.

Alcohol usage in sport and exercise

In this review we consider some of the acute and chronic effects of alcohol on human exercise and sport performance. The 1982 position stand of the American College of Sport Medicine on the use of alcohol in sport emphasized that there was little benefit for an athlete. Subsequent literature continues to demonstrate that there are adverse effects on performance. However, the literature is often confusing and disparate. We will attempt to explain the effects and speculate on the possible mechanisms. We divide the review into acute and chronic metabolic and physiological effects of alcohol on exercise performance, primarily in humans. We also review the epidemiological evidence of the associations between alcohol use and problem alcohol behaviors in various athletic groups. Finally, we review the limited data on the effectiveness of exercise therapy in the treatment of alcohol dependent patients. In spite of scientific evidence that alcohol use is, in general, detrimental (or of no benefit) to sport (exercise) performance, alcohol continues to be used by athletes both on a chronic basis and even immediately prior to sports participation. There is some encouraging but limited evidence that student-athlete alcohol use is decreasing and exercise can be effective as part of alcohol rehabilitation.

Hypertension augments ethanol-induced depression of cell shortening and intracellular Ca(2+) transients in adult rat ventricular myocytes

Ethanol, a risk factor for myocardial dysfunction, depresses myocardial contraction. This study was to determine whether ethanol-induced myocardial depression is affected by hypertension. Mechanical properties of ventricular myocytes isolated from both normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats were evaluated using a video edge-detection system. Myocytes were electrically stimulated to contract at 0.5 Hz. Contractile properties analyzed include peak twitch amplitude (PTA), time-to-PTA (TPS), time-to-90% relengthening (TR(90)), and maximal velocities of shortening/relengthening (+/-dL/dt). Intracellular Ca(2+) transients were measured as fura-2 fluorescence intensity (DeltaFFI) changes. Acute ethanol exposure (80-640 mg/dl) caused a concentration-dependent inhibition of PTA and DeltaFFI in both WKY and SHR myocytes. The extent of maximal inhibition of PTA and FFI was significantly greater in SHRs (53.7 and 38.9%) compared to the WKY group (21.0 and 25.4%). Ethanol did not affect TPS but shortened TR(90) and slowed +/-dL/dt at high concentration ranges. Interestingly, the augmented ethanol-induced inhibition of cell shortening in hypertension was greatly attenuated by Ca(2+) channel opener BayK 8644 (1 microM). These results suggest that ethanol-induced myocardial depression may be augmented in hypertension, possibly due to mechanism(s) involving sarcolemmal Ca(2+) channels.

Combined effects of caffeine and alcohol on hemodynamics and coronary artery blood flow in dogs

Alcohol intake is often followed by coffee drinking because of the universal acceptance of its sobering effect. Such effects were found inconsistent on motor functions. However, it is common belief that caffeine will antagonize the intoxicating effects of alcohol. The independent actions of caffeine and alcohol are well documented, but combined effects of short-term administration are unknown. This experimental work was designed to study the effects due to short-term administration of caffeine and alcohol on the cardiovascular system. In phase I, 30 experiments were performed in our laboratories to study the dose-response curves of both the drugs. In phases II and III, 15 dogs were subjected to 30 experiments. In phase II, caffeine, 5 mg/kg, was given i.v., followed by ethanol, 400 mg/kg i.v., and in phase III, sequence of drug administration was reversed to study the effects on hemodynamics and coronary artery blood flow. Caffeine did not show significant changes in all the cardiovascular parameters, and ethanol administration caused nonsignificant increase in heart rate, mean arterial pressure, left ventricular systolic pressure, and left ventricular (LV) mechanical work and decrease in the maximal rate of first derivative of LV pressure, stroke volume, and systemic vascular resistance. Left ventricular end-diastolic, pulmonary artery mean and right atrial pressures, pulmonary vascular resistance, myocardial oxygen consumption, and as coronary flow reserve increased as compared with controls. Combined caffeine and alcohol had synergistic effects, but when the order of drug administration was reversed (i.e., alcohol was followed by caffeine), the effect was antagonistic.

Combined effects of alcohol and nicotine on cardiovascular performance in a canine model

Alcohol and tobacco consumption are correlated. Smokers consume more alcohol than do nonsmokers, and alcohol consumers smoke more than do teetotalers. The independent effects of alcohol and nicotine on the cardiovascular system are well documented, but combined effects of short-term administration are unknown. This experimental work was designed to study the effects due to short-term administration of alcohol and nicotine on cardiovascular system. In phase I, 30 experiments were performed to study the dose-response curve of both the drugs. In phases II and III, 15 dogs were subjected to 30 experiments. In phase II, ethanol, 400 mg/kg, was given i.v., followed by nicotine 50 microg/kg, i.v., and in phase III, sequence of drug administration was reversed to study the effects on hemodynamics and coronary artery blood flow. The dose-response curve established the i.v. dose of ethanol, 400 mg/kg, and nicotine, 50 microg/kg. Ethanol administration caused a nonsignificant increase in heart rate (HR), mean arterial pressure (MAP), left ventricular systolic pressure (LVS), and left ventricular mechanical work (LVMW), and a decrease in maximal rate of increase of LV pressure per second (dP/dt), stroke volume (SV), and systemic vascular resistance (SVR). Left ventricular end-diastolic pressure (LVEDP), pulmonary artery mean pressure (PAM), right atrial pressure (RAP), pulmonary vascular resistance (PVR), myocardial oxygen consumption (MVO2), and average peak velocity of coronary blood flow (APV) had mild significant increases as compared with controls. Nicotine significantly increased heart rate, mean arterial pressures, LVEDP, and pulmonary artery, pulmonary capillary wedge, and right atrial pressures. Nicotine increased dP/dt (2,062-3,188; p < 0.006) and decreased APV (9 to 8; p < 0.03). Combined ethanol followed by nicotine had synergistic increase in HR, SD, MAP, LVS, LVEDP, pulmonary pressures, CO, SV, dP/dt (2,184 > 5,206; p < 0.005), MVO2, and LVMW. However, the excitatory effects of nicotine were attenuated when ethanol was administered after nicotine (dP/dt, reduced from 2,058 to 1,653; p < 0.04, and APV increased from 10 to 12; p < 0.02). We conclude that ethanol increased APV but had nonsignificant effects on the hemodynamics, whereas nicotine reduced the APV and had significant excitatory responses. In combination (i.v.), ethanol + nicotine produced significant synergistic excitatory effects. On the other hand, the nicotine + ethanol combination increased APV and caused attenuation of the excitatory effects of nicotine in dogs.

The effect of the ingestion of ethanol on obstruction of the left ventricular outflow tract in hypertrophic cardiomyopathy

BACKGROUND

Ethanol causes vasodilation, which might have an adverse effect, due to increased obstruction of the left ventricular outflow tract, in patients with hypertrophic obstructive cardiomyopathy. We assessed the hemodynamic effects of the ingestion of ethanol, in an amount commonly consumed socially, in patients with hypertrophic cardiomyopathy.

METHODS

We performed echocardiography in 36 patients before and several times after the ingestion of either 50 ml of 40 percent ethanol or an isocaloric placebo with the aroma of rum. Each patient received both ethanol and placebo, on different days. The patients, but not the physicians, were blinded to the content of the drink. We measured the sizes of the left atrium and left ventricle, the left-ventricular-wall thickness, blood pressure, heart rate, the degree of systolic anterior motion of the mitral valve, and the pressure gradient across the left ventricular outflow tract.

RESULTS

The ingestion of ethanol regulated in a significant drop in the mean (+/- SD) systolic blood pressure (from 130.5 +/- 18.6 to 122.5 +/- 20.3 mm Hg, P<0.001), a significant increase in systolic anterior motion of the mitral valve (from a grade of 2.1 to a grade of 2.5, P<0.001), and a 63 percent increase in the mean gradient across the left ventricular outflow tract (from 38.1 +/- 26.5 to 62.2 +/- 42.4 mm Hg, P<0.001). These changes, which were not associated with symptoms, did not occur after the ingestion of placebo.

CONCLUSION

The ingestion of a small amount of ethanol caused an increase in the gradient across the left ventricular outflow tract in patients with hypertrophic obstructive cardiomyopathy, which could have and adverse clinical effect.

Ethanol toxicity and cardiac protein synthesis in vivo

Long- and short-term alcohol consumption induce a variety of cardiovascular changes, including alterations in hemodynamic variables and tissue biochemistry. In many instances some of the perturbations may be considered as compensatory adjustments, and indeed, there is some controversy that moderate long-term consumption may cause alterations in plasma lipid profiles, conferring cardiovascular protection by reducing the incidence of coronary artery disease. In the long term, however, ethanol misuse may induce a specific disease entity, namely alcoholic heart muscle disease, and short-term ethanol exposure may also perturb tissue contractility and hemodynamic indices. The mechanisms of these changes are unknown, but central to many of the metabolic and functional disturbances are alterations in tissue protein synthesis, perhaps precipitated or exacerbated by free radial formation or by the formation of protein-acetaldehyde adducts. Methods for measuring protein synthesis in vivo are reviewed, and their application to elucidating the mechanisms involved in cardiac abnormalities is described, including the effects of ethanol. Our results demonstrate that the effects of alcohol toxicity also occur at the subcellular level, and the synthesis of mitochondrial proteins are reduced in vivo, perhaps even contribution to defects in energy generation, the normal function of which is required to maintain contractility.

Synthesis of ventricular mitochondrial proteins in vivo: effect of acute ethanol toxicity

Most studies on the pathological responses of the heart to ethanol have been conducted in isolated systems. The objectives of this study were to determine (1) the synthesis rate of ventricular mitochondrial proteins in vivo and (2) whether the synthesis rates of these proteins are perturbed by acute ethanol exposure in vivo. Fractional rates of protein synthesis [defined as the percentage of tissue protein renewed each day; i.e., ks (%/day)] were determined in male Wistar rats by in vivo injection of a flooding dose of L-[4-3H] phenylalanine. Subsarcolemmal mitochondria were released by polytron treatment, and the isolation of interfibrillar mitochondria involved treatment of the cardiac homogenate with the proteolytic enzyme Nagarse. In the control rats mean ks values of 22.4%/day were observed for mixed cardiac proteins. The synthesis rates of subsarcolemmal and interfibrillar mitochondrial proteins were lower, i.e., 16.9%/day and 10.9%/day, respectively. Acute ethanol administration (75 mmol/kg body weight ip, 2.5 hr) depressed the fractional rate of protein synthesis in all cardiac fractions, including those pertaining to the mitochondria, as follows: mixed fraction--21%, p < 0.01; subsarcolemmal mitochondria--23%, p < 0.01; interfibrillar mitochondria--26%, p < 0.05; and nuclear fraction--20%, p < 0.05. In conclusion, the reduced synthesis rate of the mitochondrial proteins in response to acute ethanol exposure may in some way be partly connected with the depression in myocardial contractility and associated functional damage of mitochondrial metabolism.

Acute depressor effect of alcohol in patients with essential hypertension

To investigate the time course of the effects of alcohol on blood pressure, we studied the response of ambulatory blood pressure, neurohumoral variables, and hemodynamics to a single moderate dose of alcohol in hypertensive patients. Sixteen Japanese men (22-70 years old) with essential hypertension who were habitual drinkers were examined under standardized conditions. On the alcohol intake day, they ingested 1 ml/kg ethanol (vodka) at dinner, and on the control day they consumed a nonalcoholic beverage. The order of the two periods was randomized. Mean ambulatory blood pressure was lower in the alcohol intake period than in the control period (125 +/- 3/74 +/- 2 versus 132 +/- 4/78 +/- 2 mm Hg, p less than 0.05), and the significant depressor effect of alcohol lasted for up to 8 hours after drinking. Blood pressure on the next day did not differ with or without alcohol intake. The acute hypotensive effect of alcohol was associated with an increase in heart rate and cardiac output and with a decrease in systemic vascular resistance as determined by echocardiography. Plasma catecholamine levels and renin activity rose significantly at 2 hours after dinner, whereas vasopressin and potassium levels fell on the alcohol day. Blood glucose and serum insulin levels were comparable between the two periods. Three patients with marked alcohol-induced flush had greater hypotensive and tachycardiac responses than those who did not show an alcohol-induced flush. The change in mean blood pressure induced by alcohol was negatively correlated with age, the baseline blood pressure, and the change in plasma norepinephrine. These results indicate that the major effect of acute alcohol intake is to lower blood pressure through systemic vasodilatation in hypertensive subjects. Ambulatory blood pressure monitoring may be useful for assessing blood pressure in habitual drinkers.