A negative deflection before the R wave is called which wave?

A negative deflection before the R wave is called which wave?

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

Answer: (A)

That negative deflection before the R wave is the Q wave. In the QRS complex, the waves sequence as a small initial downward dip (the Q wave), then a upward spike (the R wave), and the following downward dip (the S wave) may come after. The T wave comes later and represents ventricular repolarization. So, the first downward deflection that precedes the R wave is called the Q wave. A small Q wave can be normal in some leads, while a larger, wider Q wave can indicate prior myocardial damage in other contexts.