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

The Pulse-Respiration Quotient: A Powerful but Untapped Parameter for Modern Studies About Human Physiology and Pathophysiology

A specific and unique aspect of cardiorespiratory activity can be captured by dividing the heart rate (HR) by the respiration rate (RR), giving the pulse-respiration quotient (PRQ = HR/RR). In this review article, we summarize the main findings of studies using and investigating the PRQ. We describe why the PRQ is a powerful parameter that captures complex regulatory states of the cardiorespiratory system, and we highlight the need to re-introduce the use of this parameter into modern studies about human physiology and pathophysiology. In particular, we show that the PRQ (i) changes during human development, (ii) is time-dependent (ultradian, circadian, and infradian rhythms), (iii) shows specific patterns during sleep, (iv) changes with physical activity and body posture, (v) is linked with psychophysical and cognitive activity, (vi) is sex-dependent, and (vii) is determined by the individual physiological constitution. Furthermore, we discuss the medical aspects of the PRQ in terms of applications for disease classification and monitoring. Finally, we explain why there should be a revival in the use of the PRQ for basic research about human physiology and for applications in medicine, and we give recommendations for the use of the PRQ in studies and medical applications.

The Impact of Ionospheric and Geomagnetic Changes on Mortality from Diseases of the Circulatory System

We investigate the impact of solar activity changes on mortality from cardiovascular causes of death in the period 1994-2011 in the Czech Republic. This period coincides with the time of solar cycle no. 23 and the surrounding minima when there was an unusually low level of solar activity. We use long-period daily time series of numbers of deaths by cause, solar activity indices (the relative sunspot number, and the intensity of solar radio flux), geomagnetic indices (Kp-the planetary index that indicates the fluctuation rate of horizontal components of the geomagnetic field, the Auroral Electrojet, and the disturbance storm time), and physical parameters describing the ionospheric effects (the critical frequency of the ionospheric F2 layer and the content of free electrons in the ionosphere). The results of the analysis confirm the hypothesis that there is no direct correlation between the geomagnetic solar index, Kp, and the number of deaths from acute myocardial infarction (code I21) or brain stroke (code I64) during the maxima of the solar cycle. On the other hand, the ionospheric parameters explain a greater part of the variability in the number of deaths for acute myocardial infarction or brain stroke than the model with solar parameters. The analysis shows that, because the values are geographically specific, the ionospheric parameters may describe the variability in the number of deaths from cardiovascular causes better than the solar indices. The cardiovascular diseases thus respond to the changes in the solar activity and to abnormal solar events indirectly through a concentration of electrical charges in the earth's environment.

Assessing seasonality in clinical research

BACKGROUND

Seasonal patterns are assumed in many fields of medicine. However, biological processes are full of variations and the possibility of chance findings can often not be ruled out.

METHODS

Using simulated data we assess whether auto correlation is helpful to minimize chance findings and test to support the presence of seasonality.

RESULTS

Autocorrelation required to cut time curves into pieces. These pieces were compared with one another using linear regression analysis. Four examples with imperfect data are given. In spite of substantial differences in the data between the first and second year of observation, and in spite of otherwise inconsistent patterns, significant positive autocorrelations were constantly demonstrated with correlation coefficients around 0.40 (SE 0.14).

CONCLUSIONS

Our data suggest that autocorrelation is helpful to support the presence of seasonality of disease, and that it does so even with imperfect data.

Chronomics of heart rate variability on earth and in space

Chronomes are time structures consisting of multifrequency rhythms, elements of chaos, and trends in chaotic and rhythmic endpoints. Chronomics maps the dynamics of organisms' broad interactions with the environment near and far, rather than merely the daily routines. We introduced the chronomics of heart rate variability (HRV), characterized by a broad time structure, that includes the prominent circadians and also ultradian (notably about 8h and about 12h) and infradian (notably about-weekly, about-yearly, and about 10-yearly) changes, in addition to undergoing trends with aging. Alterations in these HRV chronomes are known to predict the presence of disease in the near future. Thus, for the health and safety of astronauts, HRV chronomes should be assessed before, during and after the mission in the International Space Station to check for any alteration. Future work should focus on how phenomena in the cosmos, including helio- and geomagnetics, can affect physiological chronomes, those of the HRV in particular.

The occurrence of acute myocardial infarction in relation to weather conditions

The spatial and temporal changes of weather factors depend on geographical location, seasons and the time of the day. Our study examines the relationships of meteorological factors and the incidence of acute myocardial infarction (AMI). A retrospective analysis of patients diagnosed with AMI between 2000 and 2004 in Hungary (n = 81,956 patients) was carried out. Data were collected by the National Health Insurance Fund Administration (OEP) and the National Meteorology Service (OMSZ). A peak period of the occurrence of AMI was found during spring, while minimum number of events were recorded during summer. Significant difference was observed between the number of events each season (F = 34.741; p < 0.001; N = 81,956). A medium level negative correlation was found between the monthly average temperature and the occurrence of AMI (r = -0.404) during the period examined. A positive correlation was shown between front movements and the number of events per season (r = 0.053). Average barometric pressure changes, the number of front movements and the number of AMI events also showed a nearly similar seasonal deviation. Our findings show that certain meteorological factors may be related to the onset of AMI, however other factors also play an important role.

[The effects of seasonal variations and weather conditions on the occurrence of heart attacks in Hungary between 2000-2004]

INTRODUCTION

The onset of acute myocardial infarct shows circadian and seasonal variations, that are influenced by sex, age and the changes of weather conditions as well.

AIM

The purpose of our present study is to investigate whether a seasonal variation can be found in the onset of myocardial infarctions during the period under investigation, and whether certain meteorological factors (air temperature, atmospheric pressure, front movements) influence the incidence of myocardial infarction.

METHODS

Retrospective analysis has been carried out on patients admitted because of acute myocardial infarct in Hungary between 2000 and 2004 ( n=81.956). Data have been taken from the database of the National Health Insurance Fund Administration based on the International Classification of Diseases (ICD). Weather related data were provided by the National Meteorology Service.

RESULTS

Regarding seasonal distribution the peak incidence period of acute myocardial infarct was spring, whereas the lowest number of events was observed during the summer months. There was a marked difference in the number of events per season ( p<0.001). A medium level negative correlation was found between the monthly average temperature and the occurrence of heart attack ( r=-0.404) during the period examined. A positive correlation was shown between front movements and the of number of events per season ( r=0.053).

CONCLUSION

Our findings show that certain meteorological factors may be related to the onset of acute myocardial infarct, however, a number of other factors may also play an important role.

Chronomics, neuroendocrine feedsidewards and the recording and consulting of nowcasts--forecasts of geomagnetics

A multi-center four-hourly sampling of many tissues for 7 days (00:00 on April 5-20:00 to April 11, 2004), on rats standardized for 1 month in two rooms on antiphasic lighting regimens happened to start on the day after the second extremum of a moderate double magnetic storm gauged by the planetary geomagnetic Kp index (which at each extremum reached 6.3 international [arbitrary] units) and by an equatorial index Dst falling to -112 and -81 nT, respectively, the latter on the first day of the sampling. Neuroendocrine chronomes (specifically circadian time structures) differed during magnetically affected and quiet days. The circadian melatonin rhythm had a lower MESOR and lower circadian amplitude and tended to advance in acrophase, while the MESOR and amplitude of the hypothalamic circadian melatonin rhythm were higher during the days with the storm. The circadian parameters of circulating corticosterone were more labile during the days including the storm than during the last three quiet days. Feedsidewards within the pineal-hypothalamic-adrenocortical network constitute a mechanism underlying physiological and probably also pathological associations of the brain and heart with magnetic storms. Investigators in many fields can gain from at least recording calendar dates in any publication so that freely available information on geomagnetic, solar and other physical environmental activity can be looked up. In planning studies and before starting, one may gain from consulting forecasts and the highly reliable nowcasts, respectively.

Geographic and extraterrestrial aspects of morbidity and/or mortality patterns from myocardial infarction and stroke

Two authors (M.K. and M.M.) provided insight into a manuscript submitted by them elsewhere for publication and kindly offered for meta-analysis data on the monthly incidence from January 1989 up to December 2004, of 6094 cerebral infarctions, 414 intracerebral and 277 subarachnoid hemorrhages, cases admitted at the Neurological Clinic in Nové Zamky, Slovakia. Spectral components with a period exceeding (beyond = trans) the length of the calendar year--transyears--reported originally by M.K. and M.M. are here also documented linearly on original data without and after detrending by the fit of first- or second-order polynomials. For intracerebral and subarachnoidal hemorrhage, the zero-amplitude (no-rhythm) assumption is rejected (P < 0.05, not corrected for multiple testing) for the transyear but not for a precise 1.0-year trial period. As reported earlier by M.K. and M.M., the transyear's amplitude is larger than the calendar year's amplitude for all three series of stroke incidence in Slovakia. The putative importance of the new findings stems from earlier and new analyses revealing other spectral components that are presumed signatures of magnetoperiodisms, e.g. about 50- and 7-year components in about five decades of diagnostically unqualified, pooled data on stroke in Minnesota. There is, however, the danger of relatively small numbers providing artifacts for loosely defined transyears. The original cosinor approach by M.K. and M.M., testing anticipated periods, had its strength. The observation of a quindecadal component in mortality from strokes in Minnesota supports the presence of signatures of effects from extraterrestrial space in acute human pathology such as strokes, myocardial infarctions and sudden cardiac death. Magnetoperiodic mechanisms remain to be investigated further as added strokes accumulate in Nové Zamky and greater Slovakia as well as for sudden cardiac death where transyears have been documented in the Czech Republic, in Arkansas and particularly in Minnesota, but not elsewhere (as yet?). This study is also a plea for worldwide access to morbidity, mortality and natality data that constitute a largely unexploited treasure, brought to the fore mainly for relatively short-term comparisons of the effect of interventions against the fiction of imaginary baselines.

Plasma catecholamines: follow-up on 10-year study in health and cardiovascular disease

The predictive value of blood pressure (BP), heart rate (HR), and catecholamines in terms of any subsequent development of cardiovascular disease was investigated. Systolic (S) and diastolic (D) BP, HR, epinephrine (E) and norepinephrine (NE) were measured three times a year in 1980, 1984, and 1989 on 20 clinically healthy subjects, 18 patients with 'essential hypertension', and 22 patients with angina pectoris. Of the 22 patients in the latter group, 15 died during a 2-year follow-up (1990-1991). Each individual data series was analyzed by single cosinor to assess the circannual variation. Results were summarized by population-mean cosinor for each group. Parameter tests were used to compare the circannual rhythm characteristics among the different patient groups. A circannual rhythm was invariably demonstrated on a group basis (P < 0.05). Differences in MESOR and/or circannual amplitude were found among the different groups. In particular, patients with angina pectoris who will die within the 2-year follow-up differ in terms of their E and NE from all other patient groups, a difference already detected at the beginning of the study, more than 10 years before they die. A similar separation is not achieved in terms of BP or HR.

Near-transyear in solar magnetism

Daily data on solar magnetism, available from May 1975 to April 2002, were analyzed by linear-nonlinear rhythmometry, with particular focus on the near-transyear, slightly longer than the calendar year. The time structure of solar magnetism is compared to that of solar activity, gauged by Wolf numbers. An about 27-day component corresponding to the solar rotation period, is common to both variables but differs in harmonic content. About 10-year component characterizes solar activity but not solar magnetism. A near-transyear with a period of about 1.05 years is detected in solar magnetism. In solar activity, a near-transyear is also found but its period of about 1.10 years is longer than that characterizing solar magnetism, and it may be paired with an about 0.9-year component to correspond to an about 10-year modulation in amplitude or phase of an about-yearly component.

Prokaryotic and eukaryotic unicellular chronomics

An impeccable time series, published in 1930, consisting of hourly observations on colony advance in a fluid culture of E. coli, was analyzed by a periodogram and power spectrum in 1961. While the original senior author had emphasized specifically periodicity with no estimate of period length, he welcomed further analyses. After consulting his technician, he knew of no environmental periodicity related to human schedules other than an hourly photography. A periodogram analysis in 1961 showed a 20.75-h period. It was emphasized that "... the circadian period disclosed is not of exactly 24-h length." Confirmations notwithstanding, a committee ruled out microbial circadian rhythms based on grounds that could have led to a different conclusion, namely first, the inability of some committee members to see (presumably by eyeballing) the rhythms in their own data, and second, what hardly follows, that there were "too many analyses" in the published papers. Our point in dealing with microbes and humans is that analyses are indispensable for quantification and for discovering a biologically novel spectrum of cyclicities, matching physical ones. The scope of circadian organization estimated in 1961 has become broader, including about 7-day, about half-yearly, about-yearly and ex-yearly and decadal periodisms, among others. Microbial circadians have become a field of their own with eyeballing, yet time-microscopy can quantify characteristics with their uncertainties and can assess broad chronomes (time structures) with features beyond circadians. As yet only suggestive differences between eukaryotes and prokaryotes further broaden the perspective and may lead to life's sites of origin and to new temporal aspects of life's development as a chronomic tree by eventual rhythm dating in ontogeny and phylogeny.