On a normal EKG tracing, the first wave to show a downward deflection is a:

On a normal EKG tracing, the first wave to show a downward deflection is a:
A . P wave
B . Rwave
C . Swave
D . Qwave

View Answer

Answer: D

Explanation:

On a normal EKG (electrocardiogram) tracing, the first wave to show a downward deflection is the Q wave. The EKG tracing consists of several waves: the P wave (representing atrial depolarization), the QRS complex (representing ventricular depolarization), and the T wave (representing ventricular repolarization). The Q wave is the initial negative deflection after the P wave and before the R wave in the QRS complex.

Reference: Nationally Registered Certified Medical Assistant study materials and standard cardiology references.