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.
It is measured from the beginning of the QRS complex to the end of the T wave. At a heart rate of 70 beats per minute it is usually about 0.35 seconds in duration, but the duration of the QT interval is very heart rate dependent. The lower the heart rate is, the longer the QT interval.or example if there is 0.6 seconds between beats, and there are 60 seconds per minute, then the heart rate would be 100 beats per minute [(60 sec/minute / (0.6 sec/beat)]. The RR interval is measured from the peak of one QRS complex (R wave) to the peak of the next QRS complex.