Acute effects of ethanol on action potential and intracellular Ca(2+) transient in cardiac ventricular cells: a simulation study

Alcohol is neither a risk factor nor a protective factor for sudden cardiac death and/or fatal ventricular arrhythmia: A population-based study with genetic traits and alcohol consumption in the UK Biobank

BACKGROUND

The association between alcohol consumption and the risk of sudden cardiac death and/or fatal ventricular arrhythmia remains controversial.

OBJECTIVE

We analyzed the association between alcohol consumption, genetic traits for alcohol metabolism, and the risk of sudden cardiac death and/or fatal ventricular arrhythmia.

METHODS

We identified 397,164 individuals enrolled between 2006 and 2010 from the UK Biobank database and followed them until 2021. Alcohol consumption was categorized as current nondrinkers (nondrinkers and ex-drinkers), mild drinkers, moderate drinkers, or heavy drinkers. Genetic traits of alcohol metabolism were stratified according to the polygenic risk score tertiles. The primary and secondary outcomes were a composite of sudden cardiac death and fatal ventricular arrhythmia as well as their individual components.

RESULTS

During follow-up (median 12.5 years), 3543 cases (0.89%) of clinical outcomes occurred. Although mild, moderate, and heavy drinkers showed deceased risks of outcomes compared with current nondrinkers, there was no prognostic difference among nondrinkers, mild drinkers, moderate drinkers, and heavy drinkers. Ex-drinkers showed an increased risk in univariate analysis, but the significance was attenuated after adjusting covariates (hazard ratio 1.19; 95% confidence interval 0.94-1.50). As a continuous variable, alcohol consumption was not associated with clinical outcomes (hazard ratio 1.01; 95% confidence interval 0.99-1.02). Consistent with these findings, there was no association between genetic traits for alcohol metabolism and the risk of clinical outcomes.

CONCLUSION

Alcohol consumption was neither a protective factor nor a risk factor for sudden cardiac death or fatal ventricular arrhythmia. Genetic traits of alcohol metabolism were not associated with the clinical prognosis.

A Common East Asian aldehyde dehydrogenase 2*2 variant promotes ventricular arrhythmia with chronic light-to-moderate alcohol use in mice

Chronic heavy alcohol use is associated with lethal arrhythmias. Whether common East Asian-specific aldehyde dehydrogenase deficiency (ALDH2*2) contributes to arrhythmogenesis caused by low level alcohol use remains unclear. Here we show 59 habitual alcohol users carrying ALDH2 rs671 have longer QT interval (corrected) and higher ventricular tachyarrhythmia events compared with 137 ALDH2 wild-type (Wt) habitual alcohol users and 57 alcohol non-users. Notably, we observe QT prolongation and a higher risk of premature ventricular contractions among human ALDH2 variants showing habitual light-to-moderate alcohol consumption. We recapitulate a human electrophysiological QT prolongation phenotype using a mouse ALDH2*2 knock-in (KI) model treated with 4% ethanol, which shows markedly reduced total amount of connexin43 albeit increased lateralization accompanied by markedly downregulated sarcolemmal Nav1.5, Kv1.4 and Kv4.2 expressions compared to EtOH-treated Wt mice. Whole-cell patch-clamps reveal a more pronounced action potential prolongation in EtOH-treated ALDH2*2 KI mice. By programmed electrical stimulation, rotors are only provokable in EtOH-treated ALDH2*2 KI mice along with higher number and duration of ventricular arrhythmia episodes. The present research helps formulate safe alcohol drinking guideline for ALDH2 deficient population and develop novel protective agents for these subjects.

The role of iNOS inhibition in the mechanism of the cardioprotective effect of new GABA and glutamic acid derivatives in the model of acute alcoholic myocardial injury in rats

The cardioprotective effects of new derivatives of glutamic acid (glufimet) and GABA (mefargin) were studied in rats exposed to acute alcohol intoxication (AAI) under conditions of selective blockade of inducible NO-synthase (iNOS). AAI induced a pronounced decrease in the contractile function of the myocardium during exercise tests (load by volume, test for adrenoreactivity, isometric exercise), caused mitochondrial dysfunction and increased processes of lipid peroxidation (LPO) in heart cells. A decrease in NO production during iNOS inhibition and AAI improved the respiratory function of mitochondria, a decreased the level of LPO products, and increased mitochondrial superoxide dismutase activity of heart cells. This led to an increase in myocardial contractility. The studied compounds, glufimet and mefargin, caused a statistically significant increase in the rates of myocardial contraction and relaxation, left ventricular pressure, and also reduced NO production. This was accompanied by a decrease in the intensity of LPO processes and an increase in the respiratory control ratio (RCR), reflecting the coupling between respiration and phosphorylation processes during activation of the respiratory chain complexes I and II. The decrease in NO concentration during selective blockade of iNOS and administration of the studied substances was less pronounced than without blockade of the enzyme. This suggests the putative effect of new derivatives of neuroactive amino acids on the NO system.

Epidemiology of Atrial Fibrillation in the 21st Century: Novel Methods and New Insights

Accompanying the aging of populations worldwide, and increased survival with chronic diseases, the incidence and prevalence of atrial fibrillation (AF) are rising, justifying the term global epidemic. This multifactorial arrhythmia is intertwined with common concomitant cardiovascular diseases, which share classical cardiovascular risk factors. Targeted prevention programs are largely missing. Prevention needs to start at an early age with primordial interventions at the population level. The public health dimension of AF motivates research in modifiable AF risk factors and improved precision in AF prediction and management. In this review, we summarize current knowledge in an attempt to untangle these multifaceted associations from an epidemiological perspective. We discuss disease trends, preventive opportunities offered by underlying risk factors and concomitant disorders, current developments in diagnosis and risk prediction, and prognostic implications of AF and its complications. Finally, we review current technological (eg, eHealth) and methodological (artificial intelligence) advances and their relevance for future prevention and disease management.

Mechanisms of cardiac ethanol toxicity and novel treatment options

Ethanol can acutely and chronically alter cardiomyocyte and whole-organ function in the heart. Importantly, ethanol acutely and chronically predisposes to arrhythmias, while chronic abuse can induce heart failure. However, the molecular mechanisms of ethanol toxicity in the heart are incompletely understood. In this review, we summarize the current mechanistic knowledge on cardiac ethanol toxicity, with a focus on druggable pathways. Ethanol effects on excitation-contraction coupling, oxidative stress, apoptosis, and cardiac metabolism, as well as effects of ethanol metabolites will be discussed. Important recent findings have been gained by investigation of acute ethanol effects. These include a renewed focus on reactive oxygen species (ROS) and induction of SR Ca²⁺ leak by CaMKII-mediated pathways downstream of ROS. Furthermore, a clinical outlook into potential novel treatment options is provided.

Addictive drugs, arrhythmias, and cardiac inward rectifiers

In many addictive drugs including alcohol and nicotine, proarrhythmic effects were reported. This review provides an overview of the current knowledge in this field (with a focus on the inward rectifier potassium currents) to promote the lacking data and appeal for their completion, thus, to improve understanding of the proarrhythmic potential of addictive drugs.

Traditional Cardiovascular Risk Factors for Incident Atrial Fibrillation

To prevent atrial fibrillation (AF), it is essential to reduce its risk factors and extend healthy life expectancy as a result. There are few reviews on the AF risk factors. We discuss them and approach the prevention of AF. We briefly review traditional risk factors for incident AF, especially focusing on high blood pressure, overweight/obesity, dyslipidemia, diabetes, tobacco smoking, and excessive drinking. When trying to prevent AF by modifying lifestyle, it is important to comprehensively utilize the risk factors for AF to predict the 10-year as an AF risk score. However, there are only 2 risk scores of AF just for the US population. There are few studies of the AF risk factors in non-Western populations. A risk score for incident AF in non-Westerners is awaited because different race and lifestyles may have different contributions as AF risk factors. An AF risk score in accordance with race could be useful for identifying persons with a high risk of AF in order to encourage them to consult a doctor and encourage lifestyle modifications before the onset of AF. (Circ J 2016; 80: 2415-2422).