Atrial Fibrillation

Atrial fibrillation (AF or A-fib) is the most common cardiac arrhythmia (irregular heart beat). It may cause no symptoms, but it is often associated with palpitations, fainting, chest pain, or congestive heart failure. AF increases the risk of stroke; the degree of stroke risk can be up to seven times that of the average population, depending on the presence of additional risk factors (such as high blood pressure). It may be identified clinically when taking a pulse, and the presence of AF can be confirmed with an electrocardiogram (ECG or EKG) which demonstrates the absence of P waves together with an irregular ventricular rate.

In AF, the normal regular electrical impulses generated by the sinoatrial node are overwhelmed by disorganized electrical impulses usually originating in the roots of the pulmonary veins, leading to irregular conduction of impulses to the ventricles which generate the heartbeat. AF may occur in episodes lasting from minutes to days ("paroxysmal"), or be permanent in nature. A number of medical conditions increases the risk of AF, particularly mitral stenosis (narrowing of the mitral valve of the heart).

Atrial fibrillation may be treated with medications to either slow the heart rate to a normal range ("rate control") or revert the heart rhythm back to normal ("rhythm control"). Synchronized electrical cardioversion can be used to convert AF to a normal heart rhythm. Surgical and catheter-based therapies may be used to prevent recurrence of AF in certain individuals. People with AF often take anticoagulants such as warfarin to protect them from stroke, depending on the calculated risk. The prevalence of AF in a population increases with age, with 8% of people over 80 having AF. Chronic AF leads to a small increase in the risk of death. A third of all strokes are caused by AF.

This text uses material from Wikipedia licensed under CC BY-SA

Latest Spotlight News

Effects of maternal smoking continue long after birth

Early exposure to nicotine can trigger widespread genetic changes that affect formation of connections between brain cells long after birth, a new Yale-led study has found. The finding helps explains why maternal smoking ...

The brain clock that keeps memories ticking

Just as members of an orchestra need a conductor to stay on tempo, neurons in the brain need well-timed waves of activity to organize memories across time. In the hippocampus—the brain's memory center—temporal ordering ...

Fish courtship pheromone uses the brain's smell pathway

Research at the RIKEN Brain Science Institute in Japan has revealed that a molecule involved in fish reproduction activates the brain via the nose. The pheromone is released by female zebrafish and sensed by smell receptors ...

Mouse study links heart regeneration to telomere length

Researchers at the Spanish National Center for Cardiovascular Research have discovered that the ends of heart muscle cell chromosomes rapidly erode after birth, limiting the cells' ability to proliferate and replace damaged ...

Development of gut microbes and gut immunity linked

Studying twins from birth through age 2, scientists at Washington University School of Medicine in St. Louis have shown that the gut's immune system develops in sync with the gut's tens of trillions of microbes. The findings ...

Cell phones and rats: Study explores radiation exposure

For some years research teams have explored and attempted to sort out any evidence concerning a cause-effect situation with mobile phones and cancer. Interest in the question does not disappear. Scientific groups prefer to ...