A daily alcoholic drink for women or two for men might be good for heart health, compared to drinking more or not drinking at all.
But in a recent study at UC San Francisco, researchers found that alcohol has an immediate effect on the heart in patients with atrial fibrillation (AFib), the most common life-threatening heart-rhythm disorder.
The study is published in the Journal of the American College of Cardiology: Clinical Electrophysiology. One author o is Gregory Marcus, M.D.
AFib contributes to about 158,000 U.S. deaths each year and is a leading cause of stroke, as blood clots can form inside fibrillation-prone atria.
More commonly AFib causes fatigue, weakness, dizzy lightheadedness, difficulty breathing and chest pain. In AFib, the orderly pumping of blood through the atria, the heart’s upper chambers, is disrupted.
Pumping normally is driven by regular waves of electrical signal conduction along well-travelled circuits that form in the heart between cells in the muscle tissue.
But in AFib electrical properties change within the atria and electrical signals travel chaotically through the chambers’ muscles, all of which can themselves conduct and perpetuate waves of electrical activation.
As a result, the atria pump blood inefficiently. Those who are stricken with AFib may feel the heart flutter, pound, or skip beats.
In the study, the patients were all undergoing a scheduled, standard “catheter ablation” procedure, the most effective method to suppress atrial fibrillation episodes.
Preparation for ablation surgery requires the placement of catheters and electrodes in the heart chambers to monitor and pace the heart and destroy targeted tissue.
The team measured the refractory period needed by cells to recover before they could transmit electrical signals again, as well as the speed of signal conduction from one point to another within the heart.
They found alcohol exposure resulted in an average reduction of 12-milliseconds in the refractory period for tissue in the pulmonary vein, and also reduced the refractory period in much more sites throughout the atria.
The team says patients should be aware that alcohol can have immediate effects that are expected to increase the risk for arrhythmias.
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