These 10 animal facts will amaze you. Color blindness is most often a genetic visual deficiency that limits the colors that an individual can detect. Most people with this condition don't only see in black and white. The colors affected are usually limited to green and red, which often appear as shades of tan or brown.hese 10 animal facts will amaze you. Color blindness is most often a genetic visual deficiency that limits the colors that an individual can detect. Most people with this condition don't only see in black and white. The colors affected are usually limited to green and red, which often appear as shades of tan or brown.
The duration of the QT-interval varies dependent upon how fast the heart is beating, but in normal healthy people, when the heart is beating 60 beats per minute, it is between 350 and 440 milliseconds.
In particular, the QT varies with the heart rate. It shortens as the rate increases and lengthens as the rate decreases. Therefore, there is a range of normal or healthy QT intervals. In contrast, the long QT heart often recharges sluggishly or inefficiently as evidenced by a prolonged QT interval on the ECG.he QTc is the value that doctors generally use when assessing for LQTS. In this diagram, since the heart rate (RR) is the same for both examples but the QT interval is longer in the lower panel, the QTc is longer in the lower panel example.