What arrhythmia might commonly be seen on ECG in left sided heart failure?

Atrial fibrillation is commonly associated with left-sided heart failure due to the structural and functional changes that occur in the heart. In left-sided heart failure, the left atrium often becomes enlarged due to increased pressure and volume overload as the heart struggles to effectively pump blood. This enlargement can lead to the development of atrial fibrillation, characterized by rapid and irregular electrical activity in the atria.

The irregular rhythm seen in atrial fibrillation can exacerbate heart failure symptoms because it may decrease the heart's efficiency in pumping blood and can lead to an increased heart rate. The combination of reduced stroke volume and the loss of effective atrial contraction can significantly impact the hemodynamics and increase the risk for thromboembolic events, such as stroke.

Other arrhythmias listed do not typically occur as commonly in the context of left-sided heart failure. Ventricular fibrillation and sick sinus syndrome are less frequently seen in this context, while first-degree heart block is often an indicator of a less severe conduction disturbance and does not specifically relate to the changes caused by left-sided heart failure.