Which ECG lead system is primarily used for diagnosing arrhythmias?

The 12-lead system is primarily used for diagnosing arrhythmias because it provides a comprehensive view of the electrical activity of the heart from multiple angles. This system utilizes 12 electrodes placed on the body, allowing it to record the heart's electrical activity in a way that captures various heart conditions, including complex arrhythmias.

The 12-lead ECG provides detailed information about the heart's rhythm, the presence of any ischemia, and the overall electrical conduction pathways. This capability is crucial in identifying abnormalities like atrial fibrillation, ventricular tachycardia, and other arrhythmias that may not be evident with simpler systems.

While the 3-lead and 5-lead systems are useful for continuous monitoring in specific settings, they do not offer the same level of detailed information about arrhythmias as the 12-lead system. A single lead system might monitor heart rhythm but lacks the comprehensive data needed to diagnose complex arrhythmias effectively. This makes the 12-lead system the standard choice for thorough evaluation and diagnosis in clinical practice.