Number 117 (Story #1), March 8, 1993 by Phillip F. Schewe and Ben Stein HEALTHY AND DISEASED HEARTS display distinctly different patterns in the time intervals between heartbeats, a new experiment shows. For the healthy heart, the intervals are arranged in a complex fashion even over tens of thousands of heartbeats, with a long interval-short interval pattern emerging on all time scales, regardless of whether the 1st and 2nd, or 1st and 1000th, intervals are being compared. No such pattern exists for the severely diseased hearts studied in the experiment; the lengths of the intervals for the diseased hearts fluctuate in a manner reminiscent of a random walk. Physicians may one day be able to use information of this nature as an aid in diagnosing patients. (C.-K. Peng (617-353-9460) et al., Physical Review Letters, 1 March 1993.)