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Frontiers in Cardiovascular Medicine 2023The pressure-volume (P-V) relationships of the left ventricle are the classical benchmark for studying cardiac mechanics and pumping function. Perturbations in the P-V...
INTRODUCTION
The pressure-volume (P-V) relationships of the left ventricle are the classical benchmark for studying cardiac mechanics and pumping function. Perturbations in the P-V relationship (or P-V loop) can be informative and guide the management of heart failure, hypovolemia, and aortic occlusion. Traditionally, P-V loop analyses have been limited to a single-beat P-V loop or an average of consecutive P-V loops (e.g., 10 cardiac cycles). While there are several algorithms to obtain single-beat estimations of the end-systolic and end-diastolic pressure-volume relations (i.e., ESPVR and EDPVR, respectively), there remains a need to better evaluate the variations in P-V relationships longitudinally over time. This is particularly important when studying acute and transient hemodynamic and cardiac events, such as active hemorrhage or aortic occlusion. In this study, we aim to investigate the variability in P-V relationships during hemorrhagic shock and aortic occlusion, by leveraging on a previously published porcine hemorrhage model.
METHODS
Briefly, swine were instrumented with a P-V catheter in the left ventricle of the heart and underwent a 25% total blood volume hemorrhage over 30 min, followed by either Zone 1 complete aortic occlusion (i.e., REBOA), Zone 1 endovascular variable aortic control (EVAC), or no occlusion as a control, for 45 min. Preload-independent metrics of cardiac performance were obtained at predetermined time points by performing inferior vena cava occlusion during a ventilatory pause. Continuous P-V loop data and other hemodynamic flow and pressure measurements were collected in real-time using a multi-channel data acquisition system.
RESULTS
We developed a custom algorithm to quantify the time-dependent variance in both load-dependent and independent cardiac parameters from each P-V loop. As expected, all pigs displayed a significant decrease in the end-systolic pressures and volumes (i.e., ESP, ESV) after hemorrhage. The variability in response to hemorrhage was consistent across all three groups. However, upon introduction of REBOA, we observed significantly high levels of variability in both load-dependent and independent cardiac metrics such as ESP, ESV, and the slope of ESPVR (). For instance, pigs receiving REBOA experienced a 342% increase in ESP from hemorrhage, while pigs receiving EVAC experienced only a 188% increase. The level of variability within the EVAC group was consistently less than that of the REBOA group, which suggests that the EVAC group may be more supportive of maintaining healthier cardiac performance than complete occlusion with REBOA.
DISCUSSION
In conclusion, we successfully developed a novel algorithm to reliably quantify the single-beat and longitudinal P-V relations during hemorrhage and aortic occlusion. As expected, hemorrhage resulted in smaller P-V loops, reflective of decreased preload and afterload conditions; however, the cardiac output and heart rate were preserved. The use of REBOA and EVAC for 44 min resulted in the restoration of baseline afterload and preload conditions, but often REBOA exceeded baseline pressure conditions to an alarming level. The level of variability in response to REBOA was significant and could be potentially associated to cardiac injury. By quantifying each P-V loop, we were able to capture the variability in all P-V loops, including those that were irregular in shape and believe that this can help us identify critical time points associated with declining cardiac performance during hemorrhage and REBOA use.
PubMed: 37680564
DOI: 10.3389/fcvm.2023.1171904 -
Magnetic Resonance in Medical Sciences... Sep 2023Polarity-corrected inversion time preparation (PCTIP), a myocardial T1 mapping technique, is expected to reduce measurement underestimation in the modified Look-Locker...
Novel T1 Analysis Method to Address Reduced Measurement Accuracy Due to Irregular Heart Rate Variability in Myocardial T1 Mapping Using Polarity-corrected Inversion Time Preparation.
PURPOSE
Polarity-corrected inversion time preparation (PCTIP), a myocardial T1 mapping technique, is expected to reduce measurement underestimation in the modified Look-Locker inversion recover method. However, measurement precision is reduced, especially for heart rate variability. We devised an analysis using a recurrence formula to overcome this problem and showed that it improved the measurement accuracy, especially at high heart rates. Therefore, this study aimed to determine the effect of this analysis on the accuracy and precision of T1 measurements for irregular heart rate variability.
METHODS
A PCTIP scan using a 3T MRI scanner was performed in phantom experiment. We generated the simulated R-waves required for electrocardiogram (ECG)-gated acquisition using a signal generator set to 30 combinations. T1 map was generated using the signal train of the PCTIP images by nonlinear curve fitting using conventional and recurrence formulas. Accuracy against reference T1 and precision of heart rate variability were evaluated. To evaluate the fitting accuracy of both analyses, the relative fitting error was calculated.
RESULTS
For the longer T1, the fitting error was larger than the short T1, with the conventional analysis showing 10.1±2.0%. The recurrence formula analysis showed a small fitting error less than 1%, which was consistent for all heart rate variability patterns. In the conventional analysis, the accuracy, especially for longer T1, showed a large underestimation of the measurements and poor linearity. However, in the recurrence formula analysis, the accuracy improved at a long T1, and linearity also improved. The Bland-Altman plot showed that it varied greatly depending on the heart rate variability pattern for the longer T1 in the conventional analysis, whereas the recurrence formula analysis suppressed this variation.
CONCLUSION
T1 analysis of PCTIP using the recurrence formula analysis achieved accurate and precise T1 measurements, even for irregular heart rate variability.
PubMed: 37661369
DOI: 10.2463/mrms.mp.2023-0029 -
International Journal of Molecular... Aug 2023Atrial fibrillation (AF) is a prevalent cardiac condition predominantly affecting older adults, characterized by irregular heartbeat rhythm. The condition often leads to... (Review)
Review
Atrial fibrillation (AF) is a prevalent cardiac condition predominantly affecting older adults, characterized by irregular heartbeat rhythm. The condition often leads to significant disability and increased mortality rates. Traditionally, two therapeutic strategies have been employed for its treatment: heart rate control and rhythm control. Recent clinical studies have emphasized the critical role of early restoration of sinus rhythm in improving patient outcomes. The persistence of the irregular rhythm allows for the progression and structural remodeling of the atria, eventually leading to irreversible stages, as observed clinically when AF becomes permanent. Cardioversion to sinus rhythm alters this progression pattern through mechanisms that are still being studied. In this review, we provide an in-depth analysis of the pathophysiological mechanisms responsible for maintaining AF and how they are modified during sinus rhythm restoration using existing therapeutic strategies at different stages of clinical investigation. Moreover, we explore potential future therapeutic approaches, including the promising prospect of gene therapy.
Topics: Humans; Aged; Atrial Fibrillation; Heart Rate; Tics; Heart Diseases; Heart Atria
PubMed: 37629037
DOI: 10.3390/ijms241612859 -
Cureus Jul 2023Cardiovascular disease has become a huge burden to human health. Artificial intelligence (AI)-enabled smartwatches continuously monitor the heart rate, which...
Cardiovascular disease has become a huge burden to human health. Artificial intelligence (AI)-enabled smartwatches continuously monitor the heart rate, which potentially helps to diagnose unwarranted rhythm and irregularity problems such as tachycardia, bradycardia, and fibrillation. Deep learning (DL), convolutional neural networks (CNN), and support vector machines are various modalities of AI adopted in the field of cardiology extensively, starting from a single echocardiogram to cardiac imaging. Yet, the efficacy and safety of machine learning in healthcare have always raised valid questions for the manufacturers of various healthcare devices. It is thus challenging and promising to see how AI in medicine will affect human lives in tackling various medical conditions along with global threats such as pandemics. A case report on idiopathic ventricular tachycardia (VT) detected by an AI-aided smartwatch is presented in this paper.
PubMed: 37602056
DOI: 10.7759/cureus.42054 -
PloS One 2023Deep-sea macrobenthic body fossils are scarce due to the lack of deep-sea sedimentary archives in onshore settings. Therefore, hypothesized migrations of shallow shelf...
Deep-sea macrobenthic body fossils are scarce due to the lack of deep-sea sedimentary archives in onshore settings. Therefore, hypothesized migrations of shallow shelf taxa into the deep-sea after phases of mass extinction (onshore-offshore pattern in the literature) due to anoxic events is not constrained by the fossil record. To resolve this conundrum, we investigated 1,475 deep-sea sediment samples from the Atlantic, Pacific and Southern oceans (water depth ranging from 200 to 4,700 m), providing 41,460 spine fragments of the crown group Atelostomata (Holasteroida, Spatangoida). We show that the scarce fossil record of deep-sea echinoids is in fact a methodological artefact because it is limited by the almost exclusive use of onshore fossil archives. Our data advocate for a continuous record of deep-sea Atelostomata back to at least 104 Ma (late early Cretaceous), and literature records suggest even an older age (115 Ma). A gradual increase of different spine tip morphologies from the Albian to the Maastrichtian is observed. A subsequent, abrupt reduction in spine size and the loss of morphological inventory in the lowermost Paleogene is interpreted to be an expression of the "Lilliput Effect", related to nourishment depletion on the sea floor in the course of the Cretaceous-Paleogene (K-Pg) Boundary Event. The recovery from this event lasted at least 5 Ma, and post-K-Pg Boundary Event assemblages progress-without any further morphological breaks-towards the assemblages observed in modern deep-sea environments. Because atelostomate spine morphology is often species-specific, the variations in spine tip morphology trough time would indicate species changes taking place in the deep-sea. This observation is, therefore, interpreted to result from in-situ evolution in the deep-sea and not from onshore-offshore migrations. The calculation of the "atelostomate spine accumulation rate" (ASAR) reveals low values in pre-Campanian times, possibly related to high remineralization rates of organic matter in the water column in the course of the mid-Cretaceous Thermal Maximum and its aftermath. A Maastrichtian cooling pulse marks the irreversible onset of fluctuating but generally higher atelostomate biomass that continues throughout the Cenozoic.
Topics: Fossils; Oceans and Seas; Extinction, Biological; Biomass; Water; Biological Evolution
PubMed: 37556403
DOI: 10.1371/journal.pone.0288046 -
SAGE Open Medical Case Reports 2023Single atrium is a rare congenital heart disease characterized by complete absence of the interatrial septum. It occurs as an isolated cardiac defect, or as a part of...
Single atrium is a rare congenital heart disease characterized by complete absence of the interatrial septum. It occurs as an isolated cardiac defect, or as a part of skeletal, muscular, ophthalmologic, and vascular malformations to signify congenital syndromes. A 78-year-old male patient presented with generalized body swelling of 2 weeks duration. He had associated shortness of breath, orthopnea, productive cough, and palpitation. Upon physical examination, blood pressure = 150/75 mmHg, pulse rate = 50 bpm, respiratory rate = 24 bpm, and ° = 36.7 °C. He had signs of pleural effusion on left lung field. Cardiovascular examination revealed mean heart rate of 50 beats/min with irregularly irregular pulse rhythm, raised jugular venous pressure, and pansystolic murmur at left lower sternal border. He had tender hepatomegaly, ascites, and pitting leg edema. Chest X-ray showed cardiomegaly, prominent pulmonary trunks, and left-sided pleural effusion. Electrocardiography revealed atrial fibrillation, bifascicular block (right bundle branch block and left anterior fascicular block) with mean heart rate of 50 beats/min. Two-dimensional transthoracic echocardiography showed complete absence of interatrial septum (single atrium) without atrioventricular defect and interventricular communication. Diagnosis of heart failure secondary to congenital heart disease (single atrium) with atrial fibrillation and bifascicular block was made based on clinical and imaging evaluation. Well-tolerated symptoms of a single atrium until late adulthood could be explained by the presence of streaming or incomplete mixing of blood within the atrium, in which the more oxygenated blood is directed to the systemic circuit.
PubMed: 37529079
DOI: 10.1177/2050313X231189772 -
Materials (Basel, Switzerland) Jul 2023Biofoams are a challenge for scientists in terms of innovation. Incorporation of cellulose fibrils (CF), might help improve the microstructure of foams, thus this study...
Biofoams are a challenge for scientists in terms of innovation. Incorporation of cellulose fibrils (CF), might help improve the microstructure of foams, thus this study focuses on studying the impact of CF on the foaming properties and rheology of lentil protein (LP) foams at various pH and CF concentrations. Additionally, LP-CF mixtures were transformed into solid foams, and their microstructure, physical properties, and morphology were evaluated. CF concentration significantly impacted on LP-CF foam properties, primarily due to high viscosity values. Increased CF concentration resulted in improved FS values (up to 77 min) at all pH values. This is likely attributed to associative interactions and coacervates formation. Also, foam microstructure could be related to apparent viscosity, suggesting the role of viscosity in preserving the integrity of the wet foam structure during freezing and lyophilization processes. However, elevated viscosity values might negatively impact properties such as foaming capacity and produce denser microstructures. The microstructure and morphology analysis revealed that certain foams exhibited a sponge-like structure with open pores and semi-spherical shapes, supported by CF fibers extending and forming layers. However, the structure itself was irregular. While others exhibited non-uniform, irregular pore size, and shape, along with a denser structure. These findings contribute to understanding the behavior of LP-CF mixtures, although additional investigations on mechanical properties, biodegradability, and hydrophobicity are necessary to reach their full potential for various applications.
PubMed: 37512240
DOI: 10.3390/ma16144965 -
BMC Medical Informatics and Decision... Jul 2023Signal delineation of a standard 12-lead electrocardiogram (ECG) is a decisive step for retrieving complete information and extracting signal characteristics for each...
BACKGROUND
Signal delineation of a standard 12-lead electrocardiogram (ECG) is a decisive step for retrieving complete information and extracting signal characteristics for each lead in cardiology clinical practice. However, it is arduous to manually assess the leads, as a variety of signal morphological variations in each lead have potential defects in recording, noise, or irregular heart rhythm/beat.
METHOD
A computer-aided deep-learning algorithm is considered a state-of-the-art delineation model to classify ECG waveform and boundary in terms of the P-wave, QRS-complex, and T-wave and indicated the satisfactory result. This study implemented convolution layers as a part of convolutional neural networks for automated feature extraction and bidirectional long short-term memory as a classifier. For beat segmentation, we have experimented beat-based and patient-based approach.
RESULTS
The empirical results using both beat segmentation approaches, with a total of 14,588 beats were showed that our proposed model performed excellently well. All performance metrics above 95% and 93%, for beat-based and patient-based segmentation, respectively.
CONCLUSIONS
This is a significant step towards the clinical pertinency of automated 12-lead ECG delineation using deep learning.
Topics: Humans; Deep Learning; Heart Rate; Algorithms; Neural Networks, Computer; Electrocardiography; Signal Processing, Computer-Assisted
PubMed: 37507698
DOI: 10.1186/s12911-023-02233-0