What causes cardiac fibrillation?

Atrial fibrillation is an arrhythmia characterized by uncoordinated contractions of the heart, resulting in irregular or rapid heartbeat. It may be caused by various factors, including heart disease, hypertension, thyroid dysfunction, cardiomyopathy, and myocarditis. Heart disease refers to abnormalities in the structure or function of the heart, such as coronary artery disease, cardiomyopathy, and valvular heart disease. These conditions can lead to reduced cardiac contractility and increased cardiac load, thereby triggering atrial fibrillation. Hypertension is another common cause; long-term high blood pressure can lead to cardiac hypertrophy and impaired contractile function, predisposing individuals to arrhythmias. Thyroid hormones play a key role in regulating heart rate and contractile force. Hyperthyroidism can cause excessively rapid heartbeats, while hypothyroidism may result in bradycardia; both conditions can ultimately lead to atrial fibrillation. Cardiomyopathy is a disorder involving structural abnormalities of the heart muscle, whereas myocarditis refers to infection or inflammation affecting the myocardium. Both diseases impair the heart's contractile function and may trigger atrial fibrillation.