Precordial Bipolar Leads for Mobile ECG Applications

Advances in measurement technology and wireless signal transfer have enabled the design of new, smaller and portable—even plaster-like—electrocardiographic (ECG) measurement devices that enable patient monitoring at home or in emergency situations. The development of new, miniaturized biomedical sensors has opened up possibilities for their application, but also set new demands on signal analysis and interpretation. In particular, the new small wireless systems often utilize bipolar electrodes that have a shorter interelectrode distance (IED) and different electrode locations from those of the standard 12-lead system. This affects the quality and the information content of the signal. The general objective of this thesis was to evaluate the performance of short IED precordial bipolar ECG leads and to determine their optimal location. This thesis adopted three methods to assess the properties of new bipolar precordial ECG leads: modeling, body surface potential map (BSPM) data, and exercise ECG data. First, two realistic, three-dimensional (3D) thorax models and lead field analysis were used to evaluate whether modeling of the measuring sensitivity of ECG leads could be used as a tool for designing new ECG leads. Second, BSPM data was used to study whether short-distance bipolar leads (IED approximately 6 cm) provide an ECG signal that is adequate for clinical utilization. Third, BSPM data was used to define where a bipolar ECG lead should be located in order to maximize the ECG signal strength within healthy subjects. Finally, the value of bipolar leads for diagnosing two major cardiac conditions—left ventricular hypertrophy (LVH) and coronary artery disease (CAD)—was assessed. It was found that the modeled measuring sensitivity corresponds to the changes in actual ECG signal strength, so modeling can be useful, especially in cases where in vivo measurements are impossible such as in designing implantable applications. Based on ECG data from 236 healthy subjects, all studied bipolar ECG leads with a short IED (approximately 6 cm) provided a detectable signal when compared to a low noise level of 15 μV and considering the P-wave as the smallest parameter. The optimal location of the bipolar lead was diagonally near the chest electrodes of the standard precordial leads V2, V3, and V4 (to maximize QRS amplitude), or above the chest electrodes of leads V1 and V2 (to maximize P-wave amplitude). In the selected clinical applications, LVH and CAD, the performance of bipolar leads was surprisingly good. In differentiating LVH (n=305) and healthy subjects (n=236), the performance of a correctly positioned small bipolar lead was similar to that of the traditional Sokolow-Lyon method. When differentiating CAD (n=255) patients from non-CAD (n=126) or low-likelihood of CAD (n=198) subjects, the overall performance of bipolar lead CM5 corresponded to that of standard lead V5. These results indicate that short IED bipolar leads provide a signal that is adequate for clinical use. Furthermore, the performance of these leads was shown to be similar or even superior to that of the commonly used standard leads. It can be concluded that when correctly positioned, short IED bipolar leads are useful and can give additional value for clinical diagnostics. These results provide promising information on the applicability and potential of short IED bipolar ECG leads, and demonstrate that they are worth developing further

Planetary well-being

Tensions between the well-being of present humans, future humans, and nonhuman nature manifest in social protests and political and academic debates over the future of Earth. The increasing consumption of natural resources no longer increases, let alone equalises, human well-being, but has led to the current ecological crisis and harms both human and nonhuman well-being. While the crisis has been acknowledged, the existing conceptual frameworks are in some respects ill-equipped to address the crisis in a way that would link the resolving of the crisis with the pivotal aim of promoting equal well-being. The shortcomings of the existing concepts in this respect relate to anthropocentric normative orientation, methodological individualism that disregards process dynamics and precludes integrating the considerations of human and nonhuman well-being, and the lack of multiscalar considerations of well-being. This work derives and proposes the concept of planetary well-being to address the aforementioned conceptual issues, to recognise the moral considerability of both human and nonhuman well-being, and to promote transdisciplinary, cross-cultural discourse for addressing the crisis and for promoting societal and cultural transformation. Conceptually, planetary well-being shifts focus on well-being from individuals to processes, Earth system and ecosystem processes, that underlie all well-being. Planetary well-being is a state where the integrity of Earth system and ecosystem processes remains unimpaired to a degree that species and populations can persist to the future and organisms have the opportunity to achieve well-being. After grounding and introducing planetary well-being, this work shortly discusses how the concept can be operationalised and reflects upon its potential as a bridging concept between different worldviews.</p

Langattoman EKG-laitteen elektrodipaikkojen testaaminen mallinnusmenetelmällä ja kliinisellä datalla

Tekniikan kehitys on johtanut myös lääketieteessä langattomien mittalaitteiden kehitykseen. Uudet kannettavat ja pienikokoiset mittalaitteet saattavat kuitenkin tarvita uudenlaiset elektrodipaikat. Tämän työn tarkoituksena oli testata erilaisia bipolaarisia sydänsähkökäyriä (EKG) mittaavia elektrodikytkentöjä mallinnusmenetelmän sekä kliinisen datan avulla. Tutkimuksessa selvitettiin, kuinka yksikanavaisen pienen EKG-laitteen elektrodien välinen etäisyys ja elektrodien sijainti vaikuttaa EKG-signaalin vahvuuteen. Lisäksi tavoitteena oli selvittää, kuinka hyvin mallinnusmenetelmällä saadut tulokset vastaavat kliinisesti mitattua EKG:a. Tutkimuksessa käytettiin 2D- ja 3D-thoraxmalleja sekä kliinistä EKG-aineistoa. Mallinnus perustui elementtimenetelmään (finite difference method eli FDM) sekä kytkentäkenttäteoriaan, ja kliininen data oli valmis 236 potilaasta 120 elektrodilla mitattu EKG-pintapotentiaalikartta (body surface potential map eli BSPM). Kliinisestä datasta saatujen tulosten perusteella pienen yksikanavaisen laitteen elektrodipari kannattaa asettaa rintakehän päälle diagonaalisesti sydämen sähköisen akselin suuntaisesti, koska silloin saadaan vahva signaali. Jos signaalista halutaan saada diagnoosia varten koko EKG, perinteisen 12-kytkentäisen EKG-järjestelmän standardikytkentöjen V1 ja V2 rintaelektrodien välinen etäisyys ei vaakatasoon asetetuilla elektrodeilla riitä, sillä pienimmät parametrit saattavat hukkua kohinaan. Jos signaalista halutaan havaita vain pulssi, jopa neljäsosa tästä standardietäisyydestä voi olla riittävä. Tulokset osoittavat myös, että mallinnuksen avulla voidaan ennustaa todellista signaalin vahvuutta, koska saadut mallinnustulokset korreloivat suhteellisen hyvin kliinisen datan kanssa (r = 0.79). Täten mallinnusmenetelmää voitaisiin käyttää suunniteltaessa uusia elektrodipaikkoja uusille langattomille ja yksikanavaisille EKG-mittalaitteille. Avainsanat: thoraxmalli, elektrodien sijainti, pintapotentiaalikartta, elementtimenetelmä, kytkentäkentt

Precordial Bipolar Leads for Mobile ECG Applications

Advances in measurement technology and wireless signal transfer have enabled the design of new, smaller and portable—even plaster-like—electrocardiographic (ECG) measurement devices that enable patient monitoring at home or in emergency situations. The development of new, miniaturized biomedical sensors has opened up possibilities for their application, but also set new demands on signal analysis and interpretation. In particular, the new small wireless systems often utilize bipolar electrodes that have a shorter interelectrode distance (IED) and different electrode locations from those of the standard 12-lead system. This affects the quality and the information content of the signal. The general objective of this thesis was to evaluate the performance of short IED precordial bipolar ECG leads and to determine their optimal location. This thesis adopted three methods to assess the properties of new bipolar precordial ECG leads: modeling, body surface potential map (BSPM) data, and exercise ECG data. First, two realistic, three-dimensional (3D) thorax models and lead field analysis were used to evaluate whether modeling of the measuring sensitivity of ECG leads could be used as a tool for designing new ECG leads. Second, BSPM data was used to study whether short-distance bipolar leads (IED approximately 6 cm) provide an ECG signal that is adequate for clinical utilization. Third, BSPM data was used to define where a bipolar ECG lead should be located in order to maximize the ECG signal strength within healthy subjects. Finally, the value of bipolar leads for diagnosing two major cardiac conditions—left ventricular hypertrophy (LVH) and coronary artery disease (CAD)—was assessed. It was found that the modeled measuring sensitivity corresponds to the changes in actual ECG signal strength, so modeling can be useful, especially in cases where in vivo measurements are impossible such as in designing implantable applications. Based on ECG data from 236 healthy subjects, all studied bipolar ECG leads with a short IED (approximately 6 cm) provided a detectable signal when compared to a low noise level of 15 μV and considering the P-wave as the smallest parameter. The optimal location of the bipolar lead was diagonally near the chest electrodes of the standard precordial leads V2, V3, and V4 (to maximize QRS amplitude), or above the chest electrodes of leads V1 and V2 (to maximize P-wave amplitude). In the selected clinical applications, LVH and CAD, the performance of bipolar leads was surprisingly good. In differentiating LVH (n=305) and healthy subjects (n=236), the performance of a correctly positioned small bipolar lead was similar to that of the traditional Sokolow-Lyon method. When differentiating CAD (n=255) patients from non-CAD (n=126) or low-likelihood of CAD (n=198) subjects, the overall performance of bipolar lead CM5 corresponded to that of standard lead V5. These results indicate that short IED bipolar leads provide a signal that is adequate for clinical use. Furthermore, the performance of these leads was shown to be similar or even superior to that of the commonly used standard leads. It can be concluded that when correctly positioned, short IED bipolar leads are useful and can give additional value for clinical diagnostics. These results provide promising information on the applicability and potential of short IED bipolar ECG leads, and demonstrate that they are worth developing further

Langattoman EKG-laitteen elektrodipaikkojen testaaminen mallinnusmenetelmällä ja kliinisellä datalla

Tekniikan kehitys on johtanut myös lääketieteessä langattomien mittalaitteiden kehitykseen. Uudet kannettavat ja pienikokoiset mittalaitteet saattavat kuitenkin tarvita uudenlaiset elektrodipaikat. Tämän työn tarkoituksena oli testata erilaisia bipolaarisia sydänsähkökäyriä (EKG) mittaavia elektrodikytkentöjä mallinnusmenetelmän sekä kliinisen datan avulla. Tutkimuksessa selvitettiin, kuinka yksikanavaisen pienen EKG-laitteen elektrodien välinen etäisyys ja elektrodien sijainti vaikuttaa EKG-signaalin vahvuuteen. Lisäksi tavoitteena oli selvittää, kuinka hyvin mallinnusmenetelmällä saadut tulokset vastaavat kliinisesti mitattua EKG:a. Tutkimuksessa käytettiin 2D- ja 3D-thoraxmalleja sekä kliinistä EKG-aineistoa. Mallinnus perustui elementtimenetelmään (finite difference method eli FDM) sekä kytkentäkenttäteoriaan, ja kliininen data oli valmis 236 potilaasta 120 elektrodilla mitattu EKG-pintapotentiaalikartta (body surface potential map eli BSPM). Kliinisestä datasta saatujen tulosten perusteella pienen yksikanavaisen laitteen elektrodipari kannattaa asettaa rintakehän päälle diagonaalisesti sydämen sähköisen akselin suuntaisesti, koska silloin saadaan vahva signaali. Jos signaalista halutaan saada diagnoosia varten koko EKG, perinteisen 12-kytkentäisen EKG-järjestelmän standardikytkentöjen V1 ja V2 rintaelektrodien välinen etäisyys ei vaakatasoon asetetuilla elektrodeilla riitä, sillä pienimmät parametrit saattavat hukkua kohinaan. Jos signaalista halutaan havaita vain pulssi, jopa neljäsosa tästä standardietäisyydestä voi olla riittävä. Tulokset osoittavat myös, että mallinnuksen avulla voidaan ennustaa todellista signaalin vahvuutta, koska saadut mallinnustulokset korreloivat suhteellisen hyvin kliinisen datan kanssa (r = 0.79). Täten mallinnusmenetelmää voitaisiin käyttää suunniteltaessa uusia elektrodipaikkoja uusille langattomille ja yksikanavaisille EKG-mittalaitteille. Avainsanat: thoraxmalli, elektrodien sijainti, pintapotentiaalikartta, elementtimenetelmä, kytkentäkentt

Introduction to interdisciplinary perspectives on planetary well-being

This chapter gives an overview of the objectives of the book, presents its structure, and summarizes the content of each section and chapter. It introduces planetary well-being as a novel cross-disciplinary concept coined to foster global transformation to a more inclusive and equal expression of well-being for all. The chapter describes how researchers from different human, social, and natural sciences apply and reflect on the concept of planetary well-being in this book, demonstrating its value as an interdisciplinary and cross-cutting driver of change. The Introduction concludes that sustainability science and policy need a concept of well-being that is built on systemic and non-anthropocentric grounds.Peer reviewe

Extinction risk indices for measuring and promoting planetary well-being

The concept of planetary well-being, which stresses the persistence of lineages in ecosystems, is intimately linked to species extinction risk. Avoiding extinctions is a moral issue, as wiping out the outcomes of eons of evolutionary history and their future potential is clearly unconscionable. The concept of planetary well-being is also systemic: It is understood that species, as integral parts of ecosystems, are vital for the well-being of all systems on Earth. Yet, despite international agreements to protect biodiversity, global biodiversity loss and ecosystem degradation has continued unimpeded over the past decades. We review the role of goals and targets in the UN Convention on Biological Diversity, stressing the importance of accountability. We suggest that extinction risk assessments of the International Union for Conservation of Nature’s Red List, and associated country-level Red List Indices, provide valuable tools for guiding conservation action and for monitoring the state of planetary well-being.peerReviewe

Planetary well-being

Tensions between the well-being of present humans, future humans, and nonhuman nature manifest in social protests and political and academic debates over the future of Earth. The increasing consumption of natural resources no longer increases, let alone equalises, human well-being, but has led to the current ecological crisis and harms both human and nonhuman well-being. While the crisis has been acknowledged, the existing conceptual frameworks are in some respects ill-equipped to address the crisis in a way that would link the resolving of the crisis with the pivotal aim of promoting equal well-being. The shortcomings of the existing concepts in this respect relate to anthropocentric normative orientation, methodological individualism that disregards process dynamics and precludes integrating the considerations of human and nonhuman well-being, and the lack of multiscalar considerations of well-being. This work derives and proposes the concept of planetary well-being to address the aforementioned conceptual issues, to recognise the moral considerability of both human and nonhuman well-being, and to promote transdisciplinary, cross-cultural discourse for addressing the crisis and for promoting societal and cultural transformation. Conceptually, planetary well-being shifts focus on well-being from individuals to processes, Earth system and ecosystem processes, that underlie all well-being. Planetary well-being is a state where the integrity of Earth system and ecosystem processes remains unimpaired to a degree that species and populations can persist to the future and organisms have the opportunity to achieve well-being. After grounding and introducing planetary well-being, this work shortly discusses how the concept can be operationalised and reflects upon its potential as a bridging concept between different worldviews.peerReviewe