Tag Archives: heart problems

Even one small drink of alcohol linked to risk of atrial fibrillation

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A study of nearly 108,000 people has found that people who regularly drink a modest amount of alcohol are at increased risk of atrial fibrillation, or a condition where the heart beats in an abnormal rhythm.The study, published in the European Heart Journal [1], found that, compared to drinking no alcohol at all, just one alcoholic drink a day was linked to a 16% increased risk of atrial fibrillation over an average (median) follow-up time of nearly 14 years.

This means that while four teetotallers in 100 might develop atrial fibrillation over the period of the study, five per 100 might develop the condition if they consumed alcohol starting with slightly more than an alcoholic drink a week and more than 75% of them consumed up to one drink a day [2]. The researchers categorised one alcoholic drink as containing 12 g of ethanol, which is the equivalent of a small (120 ml) glass of wine, a small beer (330 ml) or 40 ml of spirits.

IMAGE: GRAPHICAL ABSTRACT, CREDIT: EUROPEAN HEART JOURNAL

 

It is well known that people who drink a lot of alcohol regularly are at increased risk of developing heart failure, and heart failure can increase the incidence of atrial fibrillation. Several studies have shown a slightly higher risk of heart problems for people who never drink alcohol; they often show that this risk reduces for people who drink a modest amount, and then rises sharply the more alcohol is consumed, creating a ‘J’ shape on graphs. Until now, it has not been clear whether this was also the case for atrial fibrillation.

However, in the current study led by Professor Renate Schnabel, a consultant cardiologist at the University Heart and Vascular Center, Hamburg-Eppendorf (Germany), researchers found that although low doses of alcohol were associated with a reduced risk of heart failure compared to teetotallers, a similar ‘J’ shape reduction in risk was not seen for atrial fibrillation. This suggests that the increased risk of atrial fibrillation among people drinking small amounts of alcohol was not triggered by heart failure.

Heart failure

The researchers analysed information on 107,845 people taking part in five community-based studies in Sweden, Norway, Finland, Denmark and Italy. The participants underwent medical examinations at the time they joined the studies between 1982 and 2010 and provided information on their medical histories, lifestyles, employment and education levels. A total of 100,092 participants did not have atrial fibrillation when they enrolled and their median age was nearly 48 years (range 24-97 years).

During the median follow-up period of nearly 14 years, 5,854 people developed atrial fibrillation. The associations between alcohol consumption and the risk of atrial fibrillation were similar for all types of alcoholic drinks and for men and women.

In addition to the 16% increased risk of atrial fibrillation compared to teetotallers seen in people who consumed only one alcoholic drink a day, the researchers found that the risk increased with increasing alcohol intake; up to two drinks a day was associated with a 28% increased risk and this went up to 47% for those who consumed more than four.

The exact mechanisms by which modest amounts of alcohol could trigger atrial fibrillation are not known. Studies have shown that heavy drinking over a short period of time can trigger ‘holiday heart syndrome’ in some people, and in some atrial fibrillation patients, small amounts of alcohol can trigger arrhythmia episodes.

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Substance in Chinese medicine can cause cardiac deaths: Study

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IMAGE: Medicinal plants used in traditional Chinese medicine have rarely been scientifically examined. They may contain highly active substances with side effects, such as Evodia. [Credit: University of Basel]

A medicinal plant frequently used in Traditional Chinese Medicine (TCM) by name Evodia rutaecarpa contains substances that can cause cardiac arrhythmia, say researchers from the Universities of Basel, Vienna and Utrecht.

Extracts of the plant Evodia rutaecarpa are used for a variety of symptoms, such as headaches, nausea and vomiting as well as menstrual complaints and ulcers in the mouth.

Not scientifically explored, researchers led by Professor Matthias Hamburger from the Department of Pharmaceutical Sciences at the University of Basel ventured into scientifically examining the effect of Evodia extracts in collaboration with pharmacologists and toxicologists from the University of Vienna.

To their surprise, they found that the natural substances dehydroevodiamine (DHE) and hortiamine isolated from the plant in Basel turned out to be very potent inhibitors of potassium channels in the heart muscle.

If these channels are blocked, the excitation processes in the heart muscle change, which can trigger severe heart rhythm disturbances – so-called Torsade de pointes (TdP) – and ventricular fibrillation and lead to sudden cardiac death.

Effect confirmed in animal models

The development of severe TdP arrhythmias following the administration of DHE was confirmed by researchers at the University of Utrecht in ECG studies on dogs, a model that is also used to test drug safety in the industry.

Further investigations showed that the two natural substances cause oscillations in the heart muscle cells even in very low concentrations, which can cause cardiac arrhythmia. For instance, these substances can get into a tea made from Evodia fruits.

For drugs that may potentially trigger cardiac arrhythmias, it is typically required that a cardiac examination using ECG is carried out before medication. This is especially true for heart disease patients for their risk to be assessed. To date, no clinical studies have been conducted to investigate the incidence of cardiac arrhythmias after taking Evodia preparations.

Re-evaluate security

Studies at the University of Basel have also shown that the DHE content of Evodia fruits is considerable. Hamburger currently investigates the extent to which these substances find their way into tea preparations. “If DHE and hortiamine are detected, the safety of Evodia products has to be re-evaluated,” says Hamburger. TCM medicinal plants often reach the Indian and Asian or European markets relatively uncontrolled, and they can also be purchased on the internet.

The authors of the study, therefore, call for increased vigilance regarding possible toxic effects of Evodia preparations. “The popularization of medicinal plants from other cultures entails risks. These plants can contain highly active substances with side effects, as in the case of Evodia. A closer examination of such risks is therefore indispensable to protect the population,” says Hamburger.