P Wave — ECG/EKG Terminology

Definition: The first wave of the cardiac cycle, representing atrial depolarization.

Key Facts

• Represents atrial depolarization before ventricular activation.
• Morphology and axis help identify sinus versus ectopic atrial rhythm origin.
• Absent, inverted, or variable P waves suggest non-sinus activation.

ECG Connection: P-wave pattern is foundational for classifying supraventricular rhythms.

Why It Matters: Correctly identifying atrial activity prevents misclassification of rhythm strips.