Jari Viik

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There is a lack of noninvasive pulmonary function measurement techniques suitable for continuous long-term measurement of tidal breathing in mobile subjects, although tidal breathing analysis has been shown to contain information that relates to the level airway obstruction. This paper is the first to assess the suitability of impedance pneumography (IP)(More)
New miniaturized portable electrocardiogram (ECG) measuring devices may require small interelectrode distance. However, finding a suitable location for a tiny measurement device may prove tedious, as reducing interelectrode distance reduces signal strength. The objective of the study was to define the optimal location for a very closely located (5 cm)(More)
Cardiac safety pharmacology requires in-vitro testing of all drug candidates before clinical trials in order to ensure they are screened for cardio-toxic effects which may result in severe arrhythmias. Micro-electrode arrays (MEA) serve as a complement to current in-vitro methods for drug safety testing. However, MEA recordings produce huge volumes of data(More)
BACKGROUND The purpose of the Finnish Cardiovascular Study (FINCAVAS) is to construct a risk profile--using genetic, haemodynamic and electrocardiographic (ECG) markers--of individuals at high risk of cardiovascular diseases, events and deaths. METHODS AND DESIGN All patients scheduled for an exercise stress test at Tampere University Hospital and willing(More)
The non-linear inverse relationship between RR-intervals and heart rate (HR) contributes significantly to the heart rate variability (HRV) parameters and their performance in mortality prediction. To determine the level of influence HR exerts over HRV parameters' prognostic power, we studied the predictive performance for different HR levels by applying(More)
The purpose of this study is to examine the effect of posture in the sitting and supine positions on ballistocardiography (BCG) measurements by using EMFi (electromechanical film) sensors. The experiment, measuring the subject's electrocardiography (ECG), BCG and carotid pulse (CP) signal, was repeated in the sitting and different horizontal positions.(More)
OBJECTIVE If the body fails to acclimatize at high altitude, acute mountain sickness (AMS) may result. For the early detection of AMS, changes in cardiac autonomic function measured by heart rate variability (HRV) may be more sensitive than clinical symptoms alone. The purpose of this study was to ascertain if the changes in HRV during ascent are related to(More)
Bioimpedance measurement applications range from the characterization of organic matter to the monitoring of biological signals and physiological parameters. Occasionally, multiple bioimpedances measured in different locations are combined in order to solve complex problems or produce enhanced physiological measures. The present multilead bioimpedance(More)
Short and long-term alterations of ballistocardiographic parameters (BCG) were studied in a sitting position using Electromechanical Film (EMFi) sensors. Several physiological parameters were recorded from 48 men of middle age in consecutive recordings and after a 2-week interval. The duration and amplitudes of the signal components were studied. The(More)
BACKGROUND Men and women differ in the risk of cardiovascular disease, but the underlying mechanisms are not completely understood. We examined possible sex-related differences in supine and upright cardiovascular regulation. METHODS AND RESULTS Hemodynamics were recorded from 167 men and 167 women of matching age (≈45 years) and body mass index (≈26.5)(More)