Open thoracic surgical implantation of cardiac pacemakers in rodents

Genetic engineering and implantable bioelectronics have transformed investigations of cardiovascular physiology and disease. However, the two approaches have been difficult to combine in the same species: genetic engineering is applied primarily in rodents, and implantable devices generally require large animal models. We recently developed several miniature cardiac bioelectronic devices suitable for mice and rats to combine the advantages of molecular tools and implantable devices. Successful implementation of these device-enabled studies requires microsurgery approaches that reliably interface bioelectronics to the beating heart with minimal disruption to native physiology. This protocol describes how to perform an open thoracic surgical technique for epicardial implantation of novel wireless cardiac bioelectronic devices in adult rats and has significantly lower mortality than transvenous implantation approaches. In addition, we provide the methodology for a full biocompatibility assessment of the physiological response to the implanted device. The surgical implantation procedure takes about 40 minutes to complete for an experienced operator, and up to 8 surgeries can be completed in one day. Implanted pacemakers provide programmed electrical stimulation for over 1 month. This protocol has broad applications to enable fully conscious in vivo studies of cardiovascular physiology in transgenic rodent disease models.

Successful maternal and fetal outcome in an uncorrected case of tetralogy of fallot

Tetralogy of Fallot (ToF) is the most common congenital heart defect which is associated with systemic cyanosis. Pregnancy and delivery cause dramatic alterations in cardiovascular physiology and pregnancy in women with unrepaired TOF may have a worsening in right to left shunt with an increase of the cyanosis. This possesses an elevated risk of maternal and foetal morbidity and even mortality. We report and discuss a case of a 24 years old Primigravida with uncorrected ToF. A multidisciplinary team was involved in the management of the case with the aim to minimize maternal and foetal complications. The target of the management was to perform adequate maternal surveillance by maintaining an adequate oxygen saturation and good haemoglobin levels and perform timely foetal surveillance tests in the form of Obstetric doppler. A caesarean section was performed at 35 weeks and 5 days of gestation without any maternal or fetal complications. Without optimal obstetrical or medical management, prognosis of pregnancy in patient with uncorrected ToF is poor.

Advanced computation in cardiovascular physiology: new challenges and opportunities

Recent developments in computational physiology have successfully exploited advanced signal processing and artificial intelligence tools for predicting or uncovering characteristic features of physiological and pathological states in humans. While these advanced tools have demonstrated excellent diagnostic capabilities, the high complexity of these computational 'black boxes’ may severely limit scientific inference, especially in terms of biological insight about both physiology and pathological aberrations. This theme issue highlights current challenges and opportunities of advanced computational tools for processing dynamical data reflecting autonomic nervous system dynamics, with a specific focus on cardiovascular control physiology and pathology. This includes the development and adaptation of complex signal processing methods, multivariate cardiovascular models, multiscale and nonlinear models for central-peripheral dynamics, as well as deep and transfer learning algorithms applied to large datasets. The width of this perspective highlights the issues of specificity in heartbeat-related features and supports the need for an imminent transition from the black-box paradigm to explainable and personalized clinical models in cardiovascular research. This article is part of the theme issue 'Advanced computation in cardiovascular physiology: new challenges and opportunities'.

4 Educational Impact of Targeted Neonatal Echocardiography (TNE) on Neonatal-Perinatal Medicine (NPM) Subspecialty Residents

Primary Subject area Neonatal-Perinatal Medicine Background Targeted Neonatal Echocardiography (TNE) is a real-time cardiac imaging modality used by neonatologists who have completed a minimum of one-year training in cardiovascular physiology and imaging methodology, to optimize management of neonatal cardiorespiratory compromise. TNE is provided as a clinical service, to aid in diagnosis, treatment, and monitoring of neonatal cardiovascular illness. Potential impacts of TNE on trainee education are unknown. Objectives This study aimed to describe trainees’ perspectives on existing neonatal hemodynamics education and perceived impacts of TNE on their education. Design/Methods This was a mixed quantitative and qualitative study that surveyed NPM subspecialty residents in Canada and the United States of America (USA), at centres both with and without TNE. Survey questions sought to explore current perspectives on cardiac and hemodynamics curriculum in training programs. Results 92 residents responded to the survey, of whom 24 (26%) were enrolled in a program with an active TNE service, 64 (70%) were training at a non-TNE centre, and 4 (4%) were unsure. Trainees at TNE centres were more satisfied with their overall hemodynamics training (91% vs. 69%, p=0.040; Table 1). 25% of all trainees felt they do not have sufficient hemodynamics training to prepare them for independent practice. On analysis of curriculum content, cardiac development, myocardial functioning in prematurity, and cardiac mechanics emerged as areas of knowledge gaps among all residents (Table 2). TNE centre trainees reported that bedside TNE teaching offers immediate insights into how patients respond to management decisions, while didactic TNE teaching allows for learning at a slower pace, with appropriate knowledge consolidation. Only 9% of respondents at TNE sites reported a formal process of hemodynamics review between clinical and TNE teams. 90% of respondents believed that a TNE service would positively impact their hemodynamics education by improvement in knowledge of cardiovascular physiology and management decisions. Conclusion Most trainees believed that TNE may be a valuable educational tool, with current perceived satisfaction with overall hemodynamics training higher among residents training at TNE centres. 25% of all trainees felt unprepared for transitioning to independent practice. Hence, thoughtful curriculum design for real-time and consolidation learning, with specific emphasis on content gaps, as well as working toward a formal process of hemodynamics review, should be considered.

Caloric Restriction and Cardiovascular Health: the Good, the Bad, and the Renin-Angiotensin System

Much excitement exists over the cardioprotective and life-extending effects of caloric restriction (CR). This review integrates population studies with experimental animal research to address the positive and negative impact of mild and severe CR on cardiovascular physiology and pathophysiology, with a particular focus on the renin-angiotensin system (RAS). We also highlight the gaps in knowledge and areas ripe for future physiological research.

Acute and Sub-Chronic Exposure to Artificial Sweeteners at the Highest Environmentally Relevant Concentration Induce Less Cardiovascular Physiology Alterations in Zebrafish Larvae

Artificial sweeteners are widely used food ingredients in beverages and drinks to lower calorie intake which in turn helps prevent lifestyle diseases such as obesity. However, as their popularity has increased, the release of artificial sweetener to the aquatic environment has also increased at a tremendous rate. Thus, our study aims to systematically explore the potential cardiovascular physiology alterations caused by eight commercial artificial sweeteners, including acesulfame-K, alitame, aspartame, sodium cyclamate, dulcin, neotame, saccharine and sucralose, at the highest environmentally relevant concentration on cardiovascular performance using zebrafish (Danio rerio) as a model system. Embryonic zebrafish were exposed to the eight artificial sweeteners at 100 ppb and their cardiovascular performance (heart rate, ejection fraction, fractional shortening, stroke volume, cardiac output, heartbeat variability, and blood flow velocity) was measured and compared. Overall, our finding supports the safety of artificial sweetener exposure. However, several finding like a significant increase in the heart rate and heart rate variability after incubation in several artificial sweeteners are noteworthy. Biomarker testing also revealed that saccharine significantly increase the dopamine level in zebrafish larvae, which is might be the reason for the cardiac physiology changes observed after saccharine exposure.

Medical student misconceptions in cardiovascular physiology

Students find cardiovascular physiology challenging. Misunderstandings can be due to the nature of the subject, the way it is taught, and prior knowledge, which impede learning of new concepts. Some misunderstood concepts can be corrected with teaching (i.e., preconceptions), whereas others are resistant to instruction (i.e., misconceptions). A set of questions, specifically created by a panel of physiology experts to probe difficult cardiovascular concepts, was used to identify preconceptions, misconceptions, and the effect of education level on question performance. The introductory cardiovascular lecture used in this study was created based on these questions. In-class polling of medical students’ ( n = 736) performance was performed using the Turning-Point clicker response system during lecture instruction. Results were compared with published data from undergraduates ( n = 1,076) who completed the same questions but without prior instruction. To our knowledge, there have been no studies directly comparing performance using the same instrument and large numbers of undergraduate and medical students. A higher education level was associated with increased performance (preconceptions), whereas several concepts resistant to instruction (misconceptions) were identified. Findings suggest that prior knowledge interfered with the acquisition of medical knowledge. Based on these results, potential causes for these misconceptions and remedial teaching suggestions are discussed.