If there is no R wave, the combined negative deflection is called a ______ waves.

If there is no R wave, the combined negative deflection is called a ______ waves.

• A. QS waves
• B. Q waves
• C. S waves
• D. R waves

Answer: (A)

The key idea is what the QRS complex looks like when the R wave is absent. In a normal QRS, you have a small initial downward deflection (Q), a tall upward spike (R), and a downward deflection after that (S). If the R wave never appears, there’s no positive peak to ride above the baseline; the trace becomes a continuous negative deflection from the start to the end of the complex. That pattern is called a QS complex (QS waves).

So the combined negative deflection without an R wave fits the description of QS waves. A Q wave alone would imply a negative deflection that’s followed by an R, which isn’t present here. An S wave by itself implies an R preceded it with a positive deflection, and without an R, you don’t have a true S wave. An R wave is the positive component, which is missing in this scenario.