<P> The QRS complex is a name for the combination of three of the graphical deflections seen on a typical electrocardiogram ( EKG or ECG ) . It is usually the central and most visually obvious part of the tracing . It corresponds to the depolarization of the right and left ventricles of the human heart . In adults , it normally lasts 0.06 -- 0.10 s ; in children and during physical activity , it may be shorter . The Q , R , and S waves occur in rapid succession , do not all appear in all leads , and reflect a single event , and thus are usually considered together . A Q wave is any downward deflection after the P wave . An R wave follows as an upward deflection , and the S wave is any downward deflection after the R wave . The T wave follows the S wave and , in some cases , an additional U wave follows the T wave . </P>
<P> The QRS complex is a name for the combination of three of the graphical deflections seen on a typical electrocardiogram ( EKG or ECG ) . It is usually the central and most visually obvious part of the tracing . It corresponds to the depolarization of the right and left ventricles of the human heart . In adults , it normally lasts 0.06 -- 0.10 s ; in children and during physical activity , it may be shorter . The Q , R , and S waves occur in rapid succession , do not all appear in all leads , and reflect a single event , and thus are usually considered together . A Q wave is any downward deflection after the P wave . An R wave follows as an upward deflection , and the S wave is any downward deflection after the R wave . The T wave follows the S wave and , in some cases , an additional U wave follows the T wave . </P>
what is the heart doing during the qrs complex
what is the heart doing during the qrs complex
depolarization of the right and left ventricles
depolarization of the right and left ventricles