A new study has linked prolonged P-wave duration to increased risk for sudden cardiac death (SCD), independent of cardiovascular risk factors and atrial fibrillation. 1 This suggests P-wave ...

There are two different rates that can be determined on an ECG. The atrial rate is indicated by the frequency of the P waves. The ventricular rate is indicated by the frequency of the QRS complexes.

The diagrams show what happens when P waves and S waves pass through the Earth. S waves do not pass through the Earth's core S waves cannot pass through the liquid outer core, but P waves can.

Because the electrical activation originates at or near the AV node, the P wave is frequently not seen; it can be buried within the QRS complex, slightly before the QRS complex or slightly after ...