Jarmila Siegelová

Non-photic solar associations of heart rate variability and myocardial infarction

Abstract Alignment of serial epidemiological, physiological, including electrocardiographic data with variations in galactic cosmic rays, geomagnetic activity, and atmospheric pressure suggests the possibility of links among these physical environmental variations and health risks, such as myocardial infarctions and ischemic strokes, among others. An increase in the incidence of myocardial infarction in association with magnetic storms, reported by several investigators from Russia, Israel, Italy and Mexico, accounts in Minnesota for a 5% ( 220 cases / year ) increase in mortality during years of maximal solar activity by comparison with years of minimal solar activity. Magnetic storms are also found to decrease heart rate variability (HRV), indicating a possible mechanism since a reduced HRV is a prognostic factor for coronary artery disease and myocardial infarction. Longitudinal electrocardiographic monitoring for a week or much longer spans in different geographic locations, notably in the auroral oval, further suggests that the decrease in HRV affects spectral regions other than that around 3.6 s (0.15– 0.40 Hz ), reportedly associated with the parasympathetic nervous system. Differences in some associations are observed from solar cycle to solar cycle, and as a function of solar cycle stage, a finding resolving controversies. Coordinated physiological and physical monitoring, the scope of an international project on the Biosphere and the Cosmos, seeks reference values for a better understanding of environmental effects on human health and for testing the merit of space weather reports that could prompt countermeasures in space and on earth. Physiological data being collected systematically worldwide and morbidity/mortality statistics from causes such as myocardial infarction and stroke constitute invaluable data bases for assessing changes within the physiological range, for detecting environmental effects and for recognizing endogenous as well as exogenous disease-risk syndromes. Timely and timed intervention may then be instituted to lower risk, in preference to exclusive current focus on treating overt disease. These chronodiagnostics are particularly important for those venturing into regions away from hospitals, such as astronauts in space.

Intra-Dialytic Electrostimulation of Leg Extensors May Improve Exercise Tolerance and Quality of Life in Hemodialyzed Patients

Hemodialyzed (HD) patients with end-stage renal disease (ESRD) exhibit lower fitness as a consequence of chronic uremic changes that trigger various structural, metabolic, and functional abnormalities in skeletal muscles. The aim of this randomized study was to compare the effect of rehabilitation (RHB) training on a bicycle ergometer and electromyostimulation (EMS) of leg extensors in HD patients with ESRD. Thirty-two HD patients (18 men/14 women; mean age 61.1 ± 8.8 years) were randomized into three groups: (i) exercise training (ET; n = 11) on bicycle ergometer 2 × 20 min; (ii) EMS (n = 11) where stimulation (10 Hz) of leg extensors was applied for 60 min; and (iii) controls (CON; n = 10) without exercise. Exercising was performed between the 2nd and the 3rd hour of HD, three times a week, 20 weeks in total. Ergometric test was performed in order to evaluate peak workload (W(peak)), 6-min corridor walking test (CWT) to evaluate the distance walked, and dynamometry of leg extensors to assess muscle power (F(max)). Urea clearance was monitored and expressed as standard parameters: spKt/V, spKt/V equilibrated (spKt/V-e), and the urea removal ratio (URR). Quality of life (QoL) was assessed by the questionnaire SF-36. A significant increase of F(max) (P = 0.040 in group ET; P = 0.032 in group EMS), of 6-min CWT (P < 0.001 in ET group; P = 0.042 in EMS group), and of W(peak) (P = 0.041 in ET group) was observed. In both exercising groups, significant increase of spKt/V, spKt/V-e, and URR was found as compared with initial values (P < 0.05). In both exercising groups, highly significant changes in summarized mental functions were found (P = 0.001); in summarized physical components, significant improvement was observed in the ET group (P = 0.006). Intradialytic RHB showed comparable positive effects on functional parameters, urea clearance, and QoL. Intradialytic EMS might represent wide therapeutic possibility in the near future.

Electrical Stimulation of Skeletal Muscles

The aim of this study was to investigate whether electrical stimulation of skeletal muscles could represent a rehabilitation alternative for patients with chronic heart failure (CHF). Thirty patients with CHF and NYHA class II-III were randomly assigned to a rehabilitation program using either electrical stimulation of skeletal muscles or bicycle training. Patients in the first group (n = 15) had 8 weeks of home-based low-frequency electrical stimulation (LFES) applied simultaneously to the quadriceps and calf muscles of both legs (1 h/day for 7 days/week); patients in the second group (n = 15) underwent 8 weeks of 40 minute aerobic exercise (3 times a week). After the 8-week period significant increases in several functional parameters were observed in both groups: maximal VO2 uptake (LFES group: from 17.5 +/- 4.4 mL/kg/min to 18.3 +/- 4.2 mL/kg/min, P < 0.05; bicycle group: from 18.1 +/- 3.9 mL/kg/min to 19.3 +/- 4.1 mL/kg/min, P < 0.01), maximal workload (LFES group: from 84.3 +/- 15.2 W to 95.9 +/- 9.8 W, P < 0.05; bicycle group: from 91.2 +/- 13.4 W to 112.9 +/- 10.8 W, P < 0.01), distance walked in 6 minutes (LFES group: from 398 +/- 105 m to 435 +/- 112 m, P < 0.05; bicycle group: from 425 +/- 118 m to 483 +/- 120 m, P < 0.03), and exercise duration (LFES group: from 488 +/- 45 seconds to 568 +/- 120 seconds, P < 0.05; bicycle group: from 510 +/- 90 seconds to 611 +/- 112 seconds, P < 0.03). These results demonstrate that an improvement of exercise capacities can be achieved either by classical exercise training or by home-based electrical stimulation. LFES should be considered as a valuable alternative to classical exercise training in patients with CHF.

Opportunity of detecting pre-hypertension : worldwide data on blood pressure overswinging

Overswinging or CHAT (brief for Circadian Hyper-Amplitude-Tension), that is an excessive circadian variation in blood pressure (BP), has been associated with a large increase in cardiovascular disease risk, present even in the absence of an elevated BP itself. This usually asymptomatic condition is usually overlooked by current practice based on spot-checks, because to be diagnosed, measurements need to be taken around-the-clock, preferably for 7 days at the outset. Once diagnosed, however, a usual circadian BP pattern can be restored by means of certain non-pharmacologic or pharmacologic interventions timed appropriately. Thereby, it is possible to reduce the risk of cardiovascular morbidity and mortality, cerebral ischemic events and nephropathy in particular. For the preparation of guidelines regarding the diagnosis of BP disorders and for the institution of primary as well as secondary preventive measures, it is important to know what the incidence of CHAT is on a global basis. We found 191 cases of CHAT among 1602 mostly 7-day/24-h BP profiles, obtained from several centers in different countries participating in an ongoing project on the BIOsphere and the COSmos (BIOCOS). CHAT incidence is about the same between men and women, but it is diagnosed more often among patients with borderline hypertension or with glucose intolerance. It is also more common among MESOR-hypertensive than among MESOR-normotensive individuals. Priority should be given to the development of an unobtrusive and affordable device to automatically monitor BP and to analyze the data as-one-goes, so that cardiovascular disease risk can be prevented.

Hypertension types defined by clinic and ambulatory blood pressure in 14 143 patients referred to hypertension clinics worldwide. Data from the Artemis study

Objective: The Ambulatory blood pressure Registry TEleMonitoring of hypertension and cardiovascular rISk project was designed to set up an international registry including clinic blood pressure (CBP) and ambulatory blood pressure (ABP) measurements in patients attending hypertension clinics in all five continents, aiming to assess different daily life hypertension types. Methods: Cross-sectional ABP, CBP and demographic data, medical history and cardiovascular risk profile were provided from existing databases by hypertension clinics. Hypertension types were evaluated considering CBP (≥140/90 mmHg) and 24-h ABP (≥130/80 mmHg). Results: Overall, 14 143 patients from 27 countries across all five continents were analyzed (Europe 73%, Africa 3%, America 9%, Asia 14% and Australia 2%). Mean age was 57 ± 14 years, men 51%, treated for hypertension 46%, cardiovascular disease 14%, people with diabetes 14%, dyslipidemia 33% and smokers 19%. The prevalence of hypertension was higher by CBP than by ABP monitoring (72 vs. 60%, P < 0.0001). Sustained hypertension (elevated CBP and ABP) was detected in 49% of patients. White-coat hypertension (WCH, elevated CBP with normal ABP) was more common than masked hypertension (elevated ABP with normal CBP) (23 vs. 10%; P < 0.0001). Sustained hypertension was more common in Europe and America and in elderly, men, obese patients with cardiovascular comorbidities. WCH was less common in Australia, America and Africa, and more common in elderly, obese women. Masked hypertension was more common in Asia and in men with diabetes. Smoking was a determinant for sustained hypertension and masked hypertension. Conclusion: Our analysis showed an unbalanced distribution of WCH and masked hypertension patterns among different continents, suggesting an interplay of genetic and environmental factors, and likely also different healthcare administrative and practice patterns.

Intra- and extracranial artery blood velocity during a sudden blood pressure decrease in humans

The intra- and extracerebral Doppler artery blood velocity responses to a 10-mmHg abrupt blood pressure (BP) decrease in ten healthy men were studied. This decrease was obtained using two cuffs placed over both thighs. First, cuffs were inflated to pressures greater than the arterial BP for 5 min. Next, they were deflated to 60 mmHg in order to prevent venous return from the legs. We obtained a decrease in mean arterial BP of from 101 (10) to 90 (10) mmHg [mean (SD), P < 0.01] without modifications in the heart rate [HR, 88 (14) beats min−1]. Middle cerebral artery mean blood velocity (MCAmv) decreased immediately from 50 (10) to 42 (12) cm s−1 (P < 0.05). Simultaneously, temporal superficial artery mean blood velocity (TSAmv) decreased from 11 (3) to 7 (2) cm s−1 (P < 0.05) and common carotid artery blood flow (CCAbf ) decreased from 305 (23) to 233 (33) ml min−1 (P < 0.05). After 5 s, MCAmv and CCAbf returned to baseline values, whereas TSAmv [8 (2) cm s−1], mean arterial BP [86 (10) mmHg] remained low and HR increased [92 (12) beats min−1]. TSAmv, BP and HR returned to baseline values in 1 min. These data confirm that cerebral blood flow (CBF) is very rapidly regulated but that blood flow in extracranial territories is not and that it follows the arterial BP changes.

Chronobiologically Interpreted Ambulatory Blood Pressure Monitoring in Health and Disease

To detect vascular variability anomalies (VVAs), a blood pressure and heart rate profile around the clock for at least 7 days is a start. As a minimum, measurement every 60 or preferably 30 minutes for a week is needed, to be continued if abnormality is found, to assess the about 24-hour (circadian) variability that exists in all individuals. As a first dividend, one then also obtains a glimpse of 2 of the very many longer-than-circadian periodicities, the biological half-week and week. Certainly if we can have sensors and computer chips in our cars that continuously monitor the pressure over a tires life, we should be able to do the same job for ourselves for diagnostic and therapeutic decisions. Healthcare today emphasizes wellness with recommendations for exercise and a proper diet, yet these evaluations may not be adequate. BP may be measured at a visit to the doctor or before an exercise session, along with measuring body weight and performing a physical exam. The seeds of disease are planted long before they are visible, and what appears to be normal from a conventional point of view may in fact be abnormal. Hidden alterations of physiological function, masked by the bodys remarkable adaptive capabilities, may become visible through a new diagnostic and therapeutic realm—-chronobiology—-that reveals hitherto unseen abnormalities. The tools of chronobiology may yield additional dividends, such as the detection of physiological “loads” related to stress and stress relief and the undesirable effects of space weather upon personal events such as sudden cardiac death, societal events like terrorism and war, and natural disasters. Chronobiologically interpreted automatic ambulatory BP and heart rate (HR) monitoring (C-ABPM) may detect the antecedents of these types of events. C-ABPM is of interest in preventive cardiology, since it reveals new diagnoses as vascular variability anomalies (VVAs) and renders previous conventional diagnoses more reliable, such as that of an elevated BP. These VVAs include MESOR (midline-estimating statistic of rhythm)-hypertension, an elevation of the MESOR, which is diagnosed, like all other VVAs, only after 1 or preferably several replications of 7-day around-the-clock BP monitoring with available, affordable, and unobtrusive instrumentation. The recommendation for continuous C-ABPM recognizes several principles that constitute inseparably intertwined contributors to severe cardio-, cerebro- and renovascular diesase. C-ABPM gauges wear and tear of genetics, physical loads, and in particular mental stress placed upon individuals from “womb to tomb” by daily life, including weather in extraterrestrial space as well as that on earth, as a continuous surveillance paradigm preventing us from flying blind to a change from less than 5% to near 100% in the risk of a stroke within 6 years.

Variability of ambulatory arterial stiffness index and of 24-h blood pressure values in patients monitored for 6 consecutive days.

The papaper deals with variability of ambulatory arterial stiffness index and of 24-h blood pressure values in patients monitored for 6 consecutive days.

Day-to-day variability of 24-h mean values of SBP and DBP in patients monitored for 7 consecutive days.

Výsledky ukazaly velkou proměnlivost průměrných dennich a nocnich hodnot systolickeho a diastolickeho TK a naznacily, že sledovani krevniho tlaku po dobu několika dnů je vhodnějsi pro diagnostiku a lecbu hypertenze.

HYPERTENSION PHENOTYPES DEFINED BY OFFICE AND AMBULATORY BLOOD PRESSURE IN 9,153 SUBJECTS REFERRED TO HYPERTENSION CLINICS IN FOUR CONTINENTS: THE ARTEMIS INTERNATIONAL REGISTRY: LB3.6

The paper deals with hypertension phenotypes defined by office and ambulatory blood pressure in 9,153 subjects referred to hypertension clinics in four continents: the Artemis International Registry