Przemyslaw Guzik

Poznan University of Medical Sciences · Department of Cardiology Intensive Care Therapy and Internal Medicine

Introduction: Brain-derived neurotrophic factor (BDNF) is decreased in heart failure (HF), but whether serum BDNF concentration is related to the severity of HF with reduced left ventricular (LV) ejection fraction (LVEF) <50% is uncertain. Objectives: To compare cardiac structure and function in ambulatory and clinically stable patients with HF...

The Declaration of Helsinki is a set of ethical principles to be followed by scientists involved in medical research with humans or human cells and tissues. This Declaration defines how scientific research should be planned, carried out, documented, analysed, and published. We summarise and discuss some ethical issues related to publishing origina...

Heart rate is quite regular during sinus (normal) rhythm (SR) originating from the sinus node. In contrast, heart rate is usually irregular during atrial fibrillation (AF). Complete atrioventricular block with an escape rhythm, ventricular pacing, or ventricular tachycardia are the most common exceptions when heart rate may be regular in AF. Heart...

Coronaviruses are RNA viruses causing infectious diseases. They had been responsible for 15% cases of a common cold before December 2019. With the new strain of coronavirus SARS CoV2 which causes COVID-19 disease, the ongoing pandemic surprised with the severity of symptoms and its course compared to the previously known mild respiratory tract infe...

Background: Some antihypertensive medications alter cellular energy production, presumably by modification of the mitochondrial function. In vivo studies of such effects are challenging in humans. We applied a noninvasive forearm skin measurement of the 460-nm fluorescence specific for the reduced form of nicotinamide adenine dinucleotide (NADH) t...

When individuals communicate enthusiasm for good events in their partners' lives, they contribute to a high-quality relationship; a phenomenon termed interpersonal capitalization. However, little is known when individuals are more ready to react enthusiastically to the partner's success. To address this gap, we examined whether positive and negativ...

Valence and approach-avoidance motivation are two distinct but closely related components of affect. However, little is known about how these two processes evolve and covary in a dynamic affective context. We formulated several hypotheses based on the Motivational Dimensional Model of Affect. We expected that anger would be a unique approach-relate...

Purpose Women with polycystic ovary syndrome (PCOS) present with or without biochemical hyperandrogenism (HAPCOS or non-HAPCOS, respectively). Cardiometabolic and hormonal abnormalities have been reported in women with PCOS, particularly those with hypertension. However, no direct comparison between normotensive (blood pressure <140/90 mmHg) patien...

Aims: Transient ischaemia and reperfusion (TIAR) induce early ischaemic preconditioning (IPC) in different tissues and organs, including the skin. IPC protects tissues by modifying the mitochondrial function and decreasing the amount of the reduced form of nicotinamide adenine dinucleotide (NADH). Skin 460-nm autofluorescence is proportional to th...

The trauma scoring systems in trauma surgery and traumatology are tools based on combinations of physiological measures, mechanism of injury and other categorical variables and serve to measure trauma severity. The trauma scoring systems enable to compare patients with different injuries and the quality of trauma care between distinct trauma center...

A person can reap psychological benefits when sharing their accomplishments or capitalizing with a partner. These benefits often depend on whether a partner responds with enthusiasm; however, it is unknown what prompts enthusiastic responses. In two experiments, we aimed to examine whether partners reciprocate enthusiastic responses to capitalizati...

Different forms of physical activity—endurance, resistance or dynamic power—stimulate cytokine release from various tissues to the bloodstream. Receptors for exercise-induced cytokines are present in muscle tissue, adipose tissue, liver, brain, bones, cardiovascular system, immune system, pancreas, and skin. They have autocrine, paracrine and endoc...

Heart rate asymmetry (HRA) is a physiological phenomenon caused by an unequal (asymmetric) contribution of heart rate decelerations and accelerations to the variability (variance) and microstructure of the heart rhythm of sinus origin. HRA has been studied in healthy people and patients with heart failure, diabetes, obstructive sleep apnoea, ischae...

Objective: It is well established, that thyroid hormones significantly affect skeletal muscles function, causing symptoms like myalgia and muscle weakness. Hypothyroid patients present increased levels of creatine kinase (CK), indicating muscle destruction. Lately, we proposed new serum markers of muscle disturbances in thyroid disorders - titin (...

The duration of each cardiac cycle is measured on ECG as the distance between the peaks of consecutive R waves (RR interval). Its inverse value corresponds to the heart rate (HR) changing in a beat-to-beat manner. HR accelerations are reflected as the shortenings of RR intervals while HR decelerations as the lengthening of RR intervals. HR asymmetr...

Relative consistency is a notion related to entropic parameters, most notably to Approximate Entropy and Sample Entropy. It is a central characteristic assumed for e.g., biomedical and economic time series, since it allows the comparison between different time series at a single value of the threshold parameter r. There is no formal proof for this...

Introduction: Handgrip strength (HG) and blood pressure (BP) are strongly interrelated. BP is an essential component of arterial load (AL), which modulates cardiac output. Objectives: We investigated the correlation between HG and both steady and pulsatile components of AL in subjects with acute myocardial infarction. Patients and methods: We st...

Objectives. Reduced muscular strength (measured by grip strength) has been associated with an increased risk of cardiovascular complications. Further research is needed to identify how muscular strength is associated with various markers of cardiovascular function to provide at least some mechanistic explanation for observed interrelations. We, the...

Nicotinamide adenine dinucleotide (NADH/NAD+) is involved in many important biochemical reactions in human metabolism, including participation in energy production by mitochondria. Flow Mediated Skin Fluorescence (FMSF) is a non-invasive method to study dynamic changes in the content of the reduced form of NADH by measuring the optical properties o...

This study investigated hemodynamic characteristics of obstructive sleep apnea (OSA) accompanied by hypertensive disease in obese men, in whom blood pressure was pharmacologically controlled within the normal range, not exceeding 140/90 mmHg. There were 21 severe OSA patients (mean age 54.1 ± 9.3 years, apnea-hypopnea index of 47.1 ± 18.8 episodes...

Objective: Heart rate asymmetry is a phenomenon in which the contribution of heart rate decelerations to short-term heart rate variability is greater than that of accelerations, and the contribution of accelerations to long-term and total variability is greater than that of decelerations. This has been established for short, stationary recordings,...

Gamification influences health behaviors (e.g., exercising or walking) via video games. However, little is known about whether individuals who endorse specific gaming motivations are more likely to derive health benefits from gaming. We examined whether specific gaming motives (e.g., potential health benefits) influenced Pokemon GO gaming time and...

Objectives: Left atrial fibrosis represents a substrate for atrial fibrillation (AF) and cardioembolic events. White matter hyperintensities (WMH) are commonly found on magnetic resonance imaging (MRI) and are regarded, at least partly as ischemic brain lesions. Aortic excess pressure (excessPTI) represents an extra work performed by the left ventr...

Background New index of pulse wave velocity‐to‐global longitudinal peak systolic strain (PWV/GLPSS) was reported to be associated with cardiovascular damage. We evaluated the prognostic role of this metric in survivors of acute myocardial infarction (AMI). Material and methods We investigated in 569 patients with AMI, whether PWV/GLPSS was associa...

Reduced nicotinamide adenine dinucleotide (NADH) is synthesized in the cellular nucleus, cytoplasm and mitochondria but oxidized into NAD+ almost exclusively in mitochondria. Activation of human skin by the 340 nm ultraviolet light triggers natural fluorescence at the light length of 460 nm, which intensity is proportional to the skin NADH content....

Introduction HIV patients are at higher risk for cardiovascular disease and cardiac arrhythmias which can be recorded by a handheld single‑lead ECG device. Quality of ECG depends on the skin condition, which worsens with the progression of HIV infection. Objective To study the quality of the ECG signal acquired by a mobile ECG device in patients w...

Objectives: Excess pressure and reservoir pressure are related to various clinical outcomes in cardiovascular diseases, but whether there are sex differences in healthy individuals remains uncertain. We compared phenotypes of excess pressure and reservoir pressure between healthy men and women. Methods: Different features of noninvasively record...

The cardiopulmonary exercise test (CPET) is designed to measure some physiological variables related to the function of the cardiovascular and respiratory systems during exercise. Usually, the CPET is performed either on a treadmill or a cycle ergometer. In this mini-review, we describe a set of parameters which are most commonly used to quantify C...

Running is undertaken for different reasons, including improvement or maintenance of health and fitness. Many tests are employed for the estimation of the fitness in runners. In this review, we describe five field tests (Cooper test, Conconi test, 6-Minute Walk Test, 20-meter Multistage Fitness Test, and Harvard Step Test) and one laboratory cardio...

A link between the red blood cell distribution width (RDW) and clinical outcomes in heart failure (HF) was reported for the first time in 2007. Since then, many studies have shown that an increased RDW is an independent and strong predictor of mortality and morbidity in patients with acute, decompensated or chronic HF. The evidence for such a link...

Introduction. The Reflection Index (RIDVP) derived from digital volume pulse (DVP) analysis has proved to be useful in the assessment of endothelium‑dependent vasodilation induced by albuterol. Little is known of the effect of shear‑stress‑induced vasorelaxation on RIDVP. Material and Methods. Thirty three healthy volunteers (22 females, 11 males,...

Positive affect has been related to faster cardiovascular recovery from stress. Although the family of positive affective states is diverse, no study examined whether high-approach positive affect (e.g., desire) has a different impact on peripheral physiological processes than more frequently studied low-approach positive affect (e.g., amusement)....

Objective: The reduced form of nicotinamide adenine dinucleotide (NADH) is involved in many redox reactions, including those related to the energy production in mitochondria when NADH is oxidized to NAD+. Live cell NADH content can be measured as a 460-nm autofluorescence after ultraviolet excitation. Hypoxia/anoxia during tissue ischemia ceases ae...

Methods & results: 29 young adult healthy volunteers underwent a simultaneous recording of heart rate using an ECG and a chest heart rate monitor at supine rest, during mental stress and active standing. Mean RR interval, Standard Deviation of Normal-to-Normal (SDNN) of RR intervals, and Root Mean Square of the Successive Differences (RMSSD) betwe...

Background: The repetitive ischemia and reperfusion may induce cell and tissue protection against the reperfusion-related injuries. This process, known as the post-ischaemic preconditioning (IPC), can be observed in different tissues and organs, including heart, muscles or skin. During ischemia leading to cellular hypoxia/anoxia, the amount of NADH...

Background/Introduction: The excitation by ultraviolet of the reduced form of nicotinamide adenine dinucleotide (NADH) generates emission of the fluorescence light at the length of 460 nm. In this way, dynamic changes in the NADH amount can be detected in the skin at rest, during ischaemia, and reperfusion by the flow-mediated skin fluorescence (FM...

Obstructive sleep apnea (OSA) is a condition of breathing pathology occurring during sleep, characterized by repeated episodes of upper airway obstruction. The aim of the study was to determine the occurrence of airway obstruction in smoking males with OSA in whom lung function tests had not been performed before. One hundred and four current smoke...

INTRODUCTION The excess pressure-time integral (excessPTI) and the reservoir pressure-time integral (reservoirPTI) are new metrics derived from blood pressure (BP) waveform decomposition. These markers predict cardiovascular (CV) complications and are associated with target organ damage in treated hypertensive patients or subjects with chronic and...

Nicotinamide adenine dinucleotide (NADH) is produced both in the cytoplasm and in mitochondria. However, NADH undergoes oxygenation to NAD + only in mitochondria. The NADH molecules, after activation by ultraviolet light, start emitting fluorescence at a wavelength of 460 nm. This phenomenon is used to non-invasively measure mitochondrial function...

Background: Irisin is a new adipo-myokine, encoded by the FNDC5 gene. Currently, there is a discussion regarding the relation between thyroid function and irisin concentration. This prospective study assesses the influence of thyrometabolic changes on serum irisin concentration in association with altered muscle metabolism. This is performed on a...

Finding sensitive and specific markers for sports-related concussion is both challenging and clinically important. Such biomarkers might be helpful in the management of patients with concussion (i.e. diagnosis, monitoring and risk prediction). Among many parameters, blood flow–pressure metrics and heart rate variability (HRV) have been used to gaug...

Heart rate asymmetry is a phenomenon by which the accelerations and decelerations of heart rate behave differently, and this difference is consistent and unidirectional, i.e. in most of the analyzed recordings the inequalities have the same directions. So far, it has been established for variance and runs based types of descriptors of RR intervals...

Many methods computing heart rate variability (HRV) have been applied in studies in children. Not all of these methods have a comprehensive physiological interpretation, and not all of studies are in agreement with the Task Force Standards on HRV from 1996, and the New Joint Position Statement on the advances of HRV from 2015. The study aim was to...

INTRODUCTION It is controversial whether the modification of arterial stiffness and intima-media thickness (IMT) is plausible in patients with clinically significant atherosclerosis. OBJECTIVES We evaluated the effects of the one-year pharmacological therapy on the arterial stiffness and IMT in survivors of non-ST elevation myocardial infarction (N...

Transient ST-segment elevation may be caused by conditions other than myocardial ischemia, among them intracranial hemorrhage. Recognition of the underlying etiology of these ST-segment changes is key because of the vastly different therapies used to treat them. We describe the case of a patient with massive transient J-waves and ST-segment elevati...

15 simple items. Measures four major motives for Pokémon GO playing: socializing, immersion, achievements, and health. Reliable with Cronbach's Alphas ranging from .77 to .85. Validated as predictive of Pokémon GO gaming time, Pokémon GO related physical activity and outdoor time. Extension and modification of Online Gaming Motivation Scale (Yee, N...

Mobile electrocardiographs consist of three components: a mobile device (e.g. a smartphone), an electrocardiographic device or accessory, and a mobile application. Mobile platforms are small computers with sufficient computational power, good quality display, suitable data storage, and several possibilities of data transmission. Electrocardiographi...

Background: The value of modern non-invasive indices of the left ventricle (LV) and arterial system function, and their interaction for determining prognosis in contemporarily treated patients with acute coronary syndrome (ACS) is not well established. The study aimed to determine the association of ventricular-arterial (VA) coupling, LV global lo...

Purpose of the study: Heart rate asymmetry is a physiological phenomenon caused by an unequal contribution of decelerations and accelerations to the heart rate variability (HRV), complexity and structure. HRV is generally assumed to represent the variability of sinus rhythm. In practice, the variability of RR intervals (corresponding to the ventric...

Introduction: The HR and BP responses to exercise (exercise pressor reflex, EPR) predict adverse clinical events in patients with Heart Failure (HF). Although studies have shown that hyperglycemia may induce cardiovascular autonomic dysregulation, the association between glycemic status and EPR in HF patients is poorly understood. Hypothesis: Hyper...