Atrial Fibrillation Explained

Atrial fibrillation, commonly referred to as AFib or AF, is a type of heart rhythm disorder characterized by the replacement of normal, organized electrical activity in the heart's upper chambers (atria) with chaotic, rapid electrical impulses. This condition represents a serious disruption in the atrial electrical system and is among the most prevalent types of arrhythmias. During atrial fibrillation, the atria lose their ability to contract and relax effectively, leading to a decline or complete loss of the atrial pumping function.

Understanding the Physiological Impact

The irregular and rapid signals from the atria are partially blocked by the atrioventricular (AV) node before reaching the lower chambers (ventricles), which results in an erratic and often abnormally fast heart rhythm. This leads to three key physiological characteristics of AFib: irregular ventricular rate, impaired heart function, and an increased risk of blood clot formation within the atria.

Heart Auscultation and Clinical Signs

When listening to the heart with a stethoscope, medical professionals may observe varying intensities of the first heart sound, along with an irregular heart rate. In cases where the ventricular rate becomes particularly fast, a phenomenon known as pulse deficit can occur. This means that the heart rate exceeds the peripheral pulse rate, as some heartbeats are too weak to open the aortic valve or generate sufficient arterial pressure to be felt in the extremities. As a result, the measured heart rate will appear faster than the pulse rate, a hallmark sign of atrial fibrillation in clinical settings.