Jin-Long Huang, MD, Chuen-Wang Chiou, MD, Chih-Tai Ting, MD, PhD, Ying-Tsung Chen, MD, and Shih-Ann Chen, MD
The acute stress of major natural disasters, such as an earthquake, may alter biochemical data,1 affect the psychological state,2 and may be associated with increased cardiovascular mortality.1–9 Although alterations of autonomic tone are hypothesized to be the link between such environmental stressors and mortality, autonomic tone, as reflected by heart rate variability
(HRV), has never been measured during an earthquake. The earthquake that struck the Nan-Tou
area, in the central part of Taiwan, at 1:47 A.M. on September 21, 1999, Richter scale 7.3, was one of the strongest earthquakes ever recorded in a major city in Taiwan. We studied patients who were equipped with Holter electrocardiographic monitors to investigate the effect of an earthquake on the autonomic system.