Jukka Lipponen

• University of Eastern Finland

Atrial fibrillation is often asymptomatic and intermittent making its detection challenging. A photoplethysmography (PPG) provides a promising option for atrial fibrillation detection. However, the shapes of pulse waves vary in atrial fibrillation decreasing pulse and atrial fibrillation detection accuracy. This study evaluated ten robust photoplet...

Background Atrial fibrillation (AF) is the major cause of stroke since approximately 25% of all strokes are of cardioembolic‐origin. The detection and diagnosis of AF are often challenging due to the asymptomatic and intermittent nature of AF. Hypothesis A wearable electrocardiogram (ECG)‐device could increase the likelihood of AF detection. The a...

Purpose: Heart rate variability is a commonly used measurement to evaluate functioning of autonomic nervous system, psychophysiological stress, and exercise intensity and recovery. HRV measurements contain artefacts such as extra, missed or misaligned beat detections, which can produce significant distortion on HRV parameters. In this paper, a robu...

Atrial fibrillation (AF) is a significant cause of cardioembolic strokes. AF is often symptomless and intermittent, making its detection challenging. The aim of this study was to assess the possibility to use a chest strap (Suunto Movesense) to detect AF both by cardiologists and automated algorithms. A single channel electrocardiogram (ECG) from a...

Prevalence of masticatory parafunctions, such as tooth clenching and grinding, is higher among migraineurs than non-migraineurs, and masticatory dysfunctions may aggravate migraine. Migraine predisposes to cerebrovascular disturbances, possibly due to impaired autonomic vasoregulation, and sensitization of the trigeminovascular system. The relation...

Background Though fairly benign reputation, the right bundle branch block (RBBB) can cause left ventricular mechanical dyssynchrony (LVMD). Still, the relationship between electrical disturbance and LVMD is partly unclear among these patients. Methods Thirty patients with RBBB and 60 matching controls were studied with vector electrocardiography a...

Background Systemic autonomic changes are well‐known in migraineurs. Also, masticatory dysfunctions including tooth clenching are reported to be associated with migraine. However, if those phenomena are interrelated, and how, is unclear. Moreover, the knowledge on the autonomic responses to masticatory stimuli in migraineurs is limited. Objective...

Aims The aim of this study was to investigate the contribution of depolarization and repolarization abnormalities, specially abnormalities in global electrical heterogeneity of heart in cardiovascular disease (CVD) and all-cause mortality. Methods and results Eight hundred and forty men and 911 women, average age of 63 years participated in this s...

Background: Abnormal electrical activation may cause dyssynchronous left ventricular (LV) contraction. In this study, we characterized and analyzed electrical and mechanical dyssynchrony in patient with left bundle branch block (LBBB) and healthy controls. Methods: Myocardial perfusion imaging (MPI) data from 994 patients were analyzed. Forty-th...

Type 1 diabetes is a metabolic disorder, which has been associated with decreased heart rate variability (HRV) and increased risk for adverse cardiac events. The aim of this paper was to examine HRV dynamics during a cardiorespiratory exercise test. 13 male subjects with type 1 diabetes (age 33.0±6.7 years) and 25 healthy male controls (age 33.7±7....

Mouse models are extremely important in studying cardiac pathologies and related electrophysiology, but very few mouse ECG analysis programs are readily available. Therefore, a mouse ECG analysis algorithm was developed and validated. Surface ECG (lead II) was acquired during transthoracic echocardiography from C57Bl/6J mice under isoflurane anesth...

Objective Heart rate variability (HRV) analysis of obstructive sleep apnea patients reveals an increase in sympathetic activity. Sleep disordered breathing (SDB) can be also assessed with sleep mattress sensors, as the Emfit sensor, by dividing the signal into different breathing categories. In addition to normal breathing (NB) and periodic apneas/...

Heart rate variability (HRV) is reduced in diabetes mellitus (DM) patients, suggesting dysfunction of cardiac autonomic regulation and an increased risk for cardiac events. The aim of this paper was to examine the associations of blood glucose level (BGL), glycated hemoglobin (HbA1c), and duration of diabetes with cardiac autonomic regulation asses...

Fetal cardiac monitoring using noninvasive abdominal leads can provide important information on fetal well-being. However, extraction of fetal electrocardiogram (fECG) from abdominal signals is often problematic because of the higher amplitude maternal ECG (mECG). The aim of this study was to introduce a principal component model for removing the m...

Method for estimating beat-by-beat cosRT angle from the 12-lead exercise electrocardiogram (ECG) measurement is presented. Method uses principal component regression to generate ECG waveform model, and uses this model to denoise QRS complexes and T-waves. In addition two different methods for synthetizing vector ECG from the conventional 12-lead me...

Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BP...

In this study, the correlations between blood lactate concentration (BLC), different vector electrocardiogram (VECG) parameters, ventilatory parameters and heart rate during exercise and recovery periods were investigated. The aim was to clarify the relationships between VECG parameters and different exercise intensity markers. Six (25–37 years old...

Continuous electrocardiogram, blood pressure and carotid artery ultrasound video were analyzed from 15 diabetics and 28 healthy controls. By using these measurements artery elasticity, overall baroreflex sensitivity (BRS) assessed between RR and systolic blood pressure variation, and neural BRS assessed between RR and artery diameter variation were...

In search for new biomarkers of vascular disturbances accompanying migraine, we compared the facial and hand skin temperatures in 41 women, including 12 migraine patients during the headache-free period and 29 healthy controls. Compared to the controls, the acral skin temperatures were lower in migraineurs, especially in those with right-sided head...

Kubios HRV is an advanced and easy to use software for heart rate variability (HRV) analysis. The software supports several input data formats for electrocardiogram (ECG) data and beat-to-beat RR interval data. It includes an adaptive QRS detection algorithm and tools for artifact correction, trend removal and analysis sample selection. The softwar...

The estimates of heart rate variability (HRV) low frequency (LF) and high frequency (HF) components with constant frequency bands may distort when the frequency of respiratory sinus arrhythmia induced HF component approaches the LF-HF frequency limit. In this study we present a method for dynamically estimating the LF-HF limit and dividing the spec...

Heart rate variability (HRV) is reduced in diabetes mellitus (DM) patients, suggesting dysfunction of cardiac autonomic regulation which has been associated with increased risk for pathological cardiac events. In this paper, we examined changes in HRV complexity in association to blood glucose level (BGL) and duration of diabetes. Resting HRV and B...

Nitroglycerin (NTG) often induces headaches when used to treat cardiac diseases. Such property of NTG has been widely used in modelling of migraine-like headaches. However, background reasons, predisposing to the development of NTG-headache, are less studied. The main aim of our study was to find, using NTG model, easily accessible markers of the v...

The fetal heart rate (fHR) is commonly used as an indirect indicators of fetal condition. Noninvasive fHR monitoring uses electrodes placed on the mother's abdomen. However it is challenging to detect fetal QRS (fQRS) complexes from the signals measured in this way because of different types of noise and overlapping frequencies between maternal and...

Arterial baroreflex has a significant role in regulating blood pressure. It is known that increased stiffness of the carotid sinus affects mecanotransduction of baroreceptors and therefore limits baroreceptors capability to detect changes in blood pressure. By using high resolution ultrasound video signal and continuous measurement of electrocardio...

Heart rate variability (HRV) has been observed to decrease during anesthesia, but changes in HRV during loss and recovery of consciousness have not been studied in detail. In this study, HRV dynamics during low-dose propofol (N = 10) and dexmedetomidine (N = 9) anesthesia were estimated by using time-varying methods. Standard time-domain and freque...

Heart rate variability (HRV) is reduced in diabetes mellitus (DM) patients, suggesting dysfunction of cardiac autonomic regulation which has been associated with increased risk for cardiac events. In this paper, we examined the associations of blood glucose level (BGL) and duration of diabetes with autonomic nervous system (ANS) function assessed b...

Hypoglycemia is known to affect repolarization characteristics of the heart. These changes are shown from ECG by prolonged QT-time and T-wave flattening. In this study we constructed a classifier based on these ECG parameters. By using the classifier we tried to detect hypoglycemic events from measurements of 22 test subjects. Hypoglycemic state wa...

Skin vasomotor responses to cold exposure (CE) have been measured widely and shown to be abnormal in some clinical conditions. Among other methods, monitoring of skin temperature (Tsk) changes has been applied for those purposes. We investigated such changes simultaneously in different skin areas of healthy young men during foot and facial CE. Tsk...

Hypoglycemia is known to affect the repolarization characteristics of the heart, but the mechanisms behind these changes are not completely understood. We analyzed repolarization characteristics continuously from 22 subjects during normoglycemic period, transition period (blood glucose concentration decreasing) and hypoglycemic period from nine hea...

Background: Type 1 diabetes is associated with increased risk of cardiovascular diseases and altered metabolism of cholesterol. We studied whether the markers of arterial stiffness reflecting preclinical atherosclerosis are related to markers of cholesterol metabolism in type 1 diabetes. Methods: In eighteen type 1 diabetes subjects aged from 20 to...

Hypoglycemia has been shown to affect ECG. Reported changes are prolongation of QT-interval and increased R/T amplitude ratio. These ECG changes are suggested to be connected to so-called dead in bed syndrome. Continuous analysis of ECG changes and blood glucose values, during insulin induced hypoglycemia is presented. Altogether 22 subjects were a...

The aim of the study was to investigate the correlations between blood lactate concentration, different vector ECG (VECG) parameters, ventilatory parameters and heart rate during exercise and recovery periods. Six (25-37 years old) non athlete, healthy, male subjects participated in the study. All subjects performed two different bicycle er-gospiro...

It has been observed that heart rate variability (HRV) diminishes during anesthesia, but the exact mechanisms causing it are not completely understood. The aim of this paper was to study the dynamics of HRV during low dose propofol (N=9) and dexmedetomidine (N=8) anesthesia by using state-of-the-art time-varying methods, and thereby ultimately try...

The time interval between Q-wave onset and T-wave offset, i.e., QT interval, in an ECG corresponds to the total ventricular activity, including both depolarization and repolarization times. It has been suggested that abnormal QT variability could be a marker of cardiac diseases such as ventricular arrhythmias, and QT-interval has also been observed...

Vascular endothelial growth factors (VEGFs) and their receptors (VEGF-Rs) are among the most powerful factors regulating vascular growth. However, it has remained unknown whether stimulation of VEGF-R1, VEGF-R2 or both of the receptors produces the best angiogenic responses in myocardium. The aim of this study was to compare the VEGF-R1-specific li...

A time-varying parametric spectrum estimation method for analyzing dynamics of heart rate variability (HRV) signals is presented. In the method, HRV signal is first modeled with a time-varying autoregressive model and the model parameters are solved recursively with a Kalman smoother algorithm. Time-varying spectrum estimates are then obtained from...

A software for advanced heart rate variability (HRV) analysis is presented. The software includes adaptable tools for correcting artifacts and for removing low frequency trend components. The analysis options of the software include all the commonly used time-domain, frequency-domain and nonlinear HRV parameters. Analysis results can be saved as a...

A smoothness priors approach for removing the baseline from near infrared (NIR) spectroscopy measurements is presented. Typically in NIR spectroscopy applications the baseline is removed by subtracting the mean or a linear trend from the data. The smoothness priors method is basically a time-varying high-pass filter with adjustable cut-off frequenc...

Abnormal QT variability has been suggested to be marker of several cardiac diseases. It has been also reported that abnormalities of T-wave morphology predicts impending hypoglycemia. Changes in T-wave morphology can also distort QT interval estimation, and thus, detection of these changes is important. Method of detecting changes in T-wave morphol...