Incidence of sudden cardiac death, myocardial infarction and far- and near-transyears

We analyzed cycles with periods, τ, in the range of 0.8-2.0 years, characterizing, mostly during 1999-2003, the incidence of sudden cardiac death (SCD), according to the International Classification of Diseases, 10th revision (ICD10), code I46.1. In the τ range examined, only yearly components could be documented in time series from North Carolina, USA; Tbilisi, Georgia; and Hong Kong, in the latter two locations based on relatively short time series. By contrast, in Minnesota, USA, we found only a component with a longer than (= trans) yearly (transyearly) τ of 1.39 years; the 95% confidence interval (CI) of the τ extended from 1.17 to 1.61 years, falling into the category of transyears (defined as a τ and a 95% CI between 1.0 and 2.0 years, with the limits of the 95% CI of the spectral component's τ overlapping neither of these lengths). During the same span from 1999 to 2003 in Arkansas, USA, a component of about 1-year in length was present, and in addition, one with a τ of 1.69 year with a CI extending from 1.29 to 2.07 years, a far-transyear candidate, far-transyears being defined as having a τ with a CI between 1.20 and 2.0 year, with the CI overlapping neither of these lengths. In the Czech Republic, there was also a calendar-yearly τ and one of 1.76 years. In the latter two geographic/geomagnetic areas, the about-yearly and the longer cycles' amplitudes were of similar prominence. The τs are only candidate transyears; the 95% CIs of their τs overlap the 2-year length. When a series on SCD from 1994 to 2003 from the Czech Republic was analyzed, the 95% CI of the transyear's τ no longer overlapped the 2-year length. Transyears were also found in the Czech Republic for myocardial infarctions (MI), meeting the original transyear definition in both a shorter and a longer series. Moreover, in the 1994-2003 series on MI from the Czech Republic, a near-transyear was also found, meeting the definition of a period with a 95% CI overlapping neither precisely 1.0 year nor 1.2 years, along with a far-transyear, defined as a τ between 1.2 and 2.0 years, again with the 95% CI covering neither of these lengths. Herein, we discuss near- and far-transyears more generally in the light of their background in physics and the concept of reciprocal cyclicities. © 2005 Elsevier SAS. All rights reserved.