Atrial fibrillation

It consists of a heart rhythm abnormality characterized by uncoordinated episodes of atrial electrical activity (fibrillation), causing a rapid and irregular heartbeat. It is the most frequent type of cardiac arrhythmia with a prevalence of 0.5% in the population. If left untreated, it can cause dizziness, chest pain, or fainting, as well as increase the risk of stroke and sudden death.

There is no cause as such described for atrial fibrillation. It is most often associated with structural abnormalities of the heart such as congenital heart defects, valvular, coronary or cardiomyopathies, as well as a history of surgery or heart attacks. However, sometimes it is not associated with any underlying cardiac pathology. In this regard, the following factors, in addition to the possible genetic contribution, may be related to an increased risk of developing atrial fibrillation:

  • Advanced age. the older the person, the higher the risk.
  • High blood pressure, especially if it is not controlled.
  • Obesity.
  • Hyperthyroidism and other chronic conditions such as diabetes, metabolic syndrome, chronic kidney disease, lung disease or sleep apnea.
  • Psychological or physical stress induced by surgery, pneumonia or viral infections or other diseases.
  • Excessive alcohol consumption, especially binge drinking, and the use of stimulants, including certain medications, amphetamine, caffeine or tobacco.
  • The population with European ancestry presents an increased risk of atrial fibrillation.

Its etiology has been associated with significant heterogeneity supported by clinical, genetic, and lifestyle factors. A GWAS study performed on more than 1000000 controls and more than 60000 cases, allowed to deepen the genetic causes by identifying 136 risk loci close to the genes causing cardiac defects, or important for the function and integrity of the cardiac muscle. In addition, functional analyses suggested the existence of cardiac structural remodeling associated with the development of this condition.

Symptoms

The symptomatology associated with atrial fibrillation is widely variable. Some patients have no manifestations while others may present with any of the following:

  • Sensation of rapid heartbeat, fluttering or pounding palpitations.
  • Chest pain, pressure or discomfort.
  • Dizziness, lightheadedness.
  • Fatigue, excessive tiredness or weakness.
  • Shortness of breath, decreased ability to exercise.

Prevention

Following a heart-healthy lifestyle can help prevent or treat conditions such as high blood pressure and heart disease. These changes generally include

  • Following a heart-healthy diet rich in fruits, vegetables and whole grains. Limiting salt and fat intake.
  • Exercising regularly every day and increasing physical activity.
  • Stop smoking, limit alcohol consumption, and restrict caffeine intake from products such as tea, coffee, energy drinks or cola.
  • Keep blood pressure, cholesterol levels and blood sugar levels under control.
  • Achieve or maintain a healthy weight. Being overweight increases the risk of heart disease.

Number of observed variants

13.5 million variants

Number of risk loci analyzed in the study

134 loci

Bibliography

Lippi G et al. Global epidemiology of atrial fibrillation: An increasing epidemic and public health challenge. Int J Stroke. 2021 Feb;16(2):217-221.

National Health Services [April 2022]

Center for Disease Control and Prevention [April 2022]

Mayo Clinic [April 2022]

Nielsen JB et al. Biobank-driven genomic discovery yields new insight into atrial fibrillation biology. Nature Genetics. 2018 Sep;50(9):1234-1239.

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