Which lead is most commonly designated as the "rhythm strip"?

Lead II is most commonly designated as the "rhythm strip" in electrocardiography due to its optimal positioning for assessing the heart's electrical activity. This lead provides a clear and consistent view of the P wave, QRS complex, and T wave, allowing for effective evaluation of the heart's rhythm and rate.

Lead II runs from the right arm to the left leg, making it particularly effective in capturing the vertical electrical axis of the heart. As the depolarization wave travels from the atria to the ventricles, Lead II displays a characteristic upward deflection of the P wave, which is vital for assessing arrhythmias, atrial enlargement, and other rhythm abnormalities.

In clinical practice, Lead II serves as the go-to choice for continuous monitoring because it offers a comprehensive view of overall heart rhythm. Other leads, while useful for specific diagnoses or conditions, may not provide the same clarity of rhythm information as Lead II.