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Yang GH, Zhou X, Ji WJ, Liu JX, Sun J, Shi R, Jiang TM, Li YM. Effects of a low salt diet on isolated systolic hypertension: A community-based population study. Medicine (Baltimore) 2018; 97:e0342. [PMID: 29620663 PMCID: PMC5902269 DOI: 10.1097/md.0000000000010342] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Evidence has shown that long-term sodium reduction can not only reduce blood pressure, but also provide cardiovascular benefits. To date, there is little evidence related to the effects of salt reduction on isolated systolic hypertension (ISH).A total of 126 hypertensive patients were divided into an ISH group (n = 51) and a non-ISH (NISH) group (n = 75). The members of each group were then randomly assigned to low sodium salt (LSSalt) or normal salt (NSalt) diets for 6 months. Their blood pressure was measured every 2 months. Serum plasma renin-angiotensin activity, blood biochemical assays and urinary measurements were determined at the baseline and at the end of the 6 months.At the end of the study, the mean systolic blood pressure (SBP) of the ISH LSSalt group had significantly decreased by 10.18 mm Hg (95% confidence interval (CI): 3.13 to 17.2, P = .006) compared with that of the ISH NSalt group, while the mean SBP only decreased by 5.10 mm Hg (95% CI: -2.02 to 12.2, P = .158) in the NISH LSSalt group compared with that of the NISH NSalt group. The mean diastolic blood pressure (DBP) had no significant differences in the ISH and NISH groups. No obvious renin angiotensin system activation was found after LSSalt intervention. Regarding the urinary excretion of electrolytes and blood biochemical assays, the LSSalt treatment had the same effects on the ISH group as on the NISH group.The present study showed that the SBP of ISH patients was significantly decreased with the LSSalt intervention, while neither the SBP of the NISH patients nor the DBP of either group were similarly decreased, which indicated that ISH patients were more sensitive to salt restriction.
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Kim D, Shim CY, Hong GR, Park S, Cho IJ, Chang HJ, Ha JW, Chung N. Impact of Ambulatory Blood Pressure on Early Cardiac and Renal Dysfunction in Hypertensive Patients without Clinically Apparent Target Organ Damage. Yonsei Med J 2018; 59:265-272. [PMID: 29436195 PMCID: PMC5823829 DOI: 10.3349/ymj.2018.59.2.265] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 12/18/2017] [Accepted: 01/03/2018] [Indexed: 12/23/2022] Open
Abstract
PURPOSE Impaired left ventricular (LV) global longitudinal strain (GLS) and the presence of microalbuminuria indicate early cardiac and renal dysfunction. We aimed to determine the relationships among 24-h ambulatory blood pressure (BP) variables, LV GLS, and urine albumin creatinine ratio (UACR) in hypertensive patients. MATERIALS AND METHODS A total of 130 hypertensive patients (mean age 53 years; 59 men) underwent 24-h ambulatory BP monitoring, measurements of peripheral and central BPs, and transthoracic echocardiography. Patients with apparent LV systolic dysfunction (LV ejection fraction <50%) or chronic kidney disease were not included. LV GLS was calculated using two-dimensional speckle tracking, and UACR was analyzed from spot urine samples. RESULTS In simple correlation analysis, LV GLS showed the most significant correlation with mean daytime diastolic BP (DBP) (r=0.427, p<0.001) among the various BP variables analyzed. UACR revealed a significant correlation only with night-time mean systolic BP (SBP) (r=0.253, p=0.019). In multiple regression analysis, daytime mean DBP and night-time mean SBP were independent determinants for LV GLS (β=0.35, p=0.028) and log UACR (β=0.49, p=0.007), respectively, after controlling for confounding factors. Daytime mean DBP showed better diagnostic performance for impaired LV GLS than did peripheral or central DBPs, which were not diagnostic. Night-time mean SBP showed satisfactory diagnostic performance for microalbuminuria. CONCLUSION There are different associations for daytime and night-time BP with early cardiac and renal dysfunction. Ambulatory BP monitoring provides more relevant BP parameters than do peripheral or central BPs regarding early cardiac and renal dysfunction in hypertensive patients.
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Samiei N, Bayat M, Firouzi A, Dehghani F, Parsaee M, Rahimi S, Ahmadi S, Pourmojib M, Ghaemmaghami Z, Rezaei Y, Peighambari MM. Subclinical systolic and diastolic dysfunctions in patients with metabolic syndrome and angiographically normal coronary arteries: An echocardiographic study. JOURNAL OF CLINICAL ULTRASOUND : JCU 2018; 46:195-201. [PMID: 29210085 DOI: 10.1002/jcu.22568] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/16/2017] [Accepted: 11/19/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND The metabolic syndrome (MetS), as a combination of cardiovascular risk factors, is associated with subclinical cardiovascular diseases. We sought to evaluate the subclinical myocardial dysfunctions using echocardiography in patients with normal coronary arteries. MATERIALS AND METHODS In this cross-sectional study, we assessed 50 consecutive patients with angiographically-proven normal coronary arteries and a left ventricular (LV) ejection fraction (EF) ≥55%. The diagnosis of MetS was based on the National Cholesterol Education Program/Adult Treatment Panel III criteria. All patients were examined using conventional and two-dimensional speckle tracking echocardiography for evaluating the myocardial functions. RESULTS The patients' mean age was 52.3 ± 8.3 years with 32 females (64%). LV EF, mass index, and full volume were comparable between groups. The LV myocardial performance index (0.40 ± 0.13 vs. 0.32 ± 0.10; P = .027), global longitudinal strain (GLS, -15.8 ± 4.5 vs. -19.7 ± 2.1; P < .001), and global circumferential strain (-17.9 ± 6.1 vs. -21.5 ± 3.3; P = .014) were different between patients with or without MetS, respectively. The GLS discriminated patients with MetS (area under the curve = 0.837, sensitivity 80%, specificity 88%, P < .001). CONCLUSIONS In MetS without coronary artery disease, echocardiography demonstrated subclinical systolic and diastolic dysfunction.
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Junior JFCR, Silva AS, Cardoso GA, Silvino VO, Martins MCC, Santos MAP. Androgenic-anabolic steroids inhibited post-exercise hypotension: a case control study. Braz J Phys Ther 2018; 22:77-81. [PMID: 28743567 PMCID: PMC5816078 DOI: 10.1016/j.bjpt.2017.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 05/21/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND There is evidence of hypertensive effects caused by anabolic androgenic steroids (AAS). A single exercise session promotes the acute reduction of blood pressure, but the effects of AAS on this phenomenon are unknown. OBJECTIVES To investigate the post-exercise blood pressure response in androgenic-anabolic steroid users. METHODS Thirteen AAS users (23.9±4.3 years old) and sixteen controls (22.1±4.5 years old) performed a session of aerobic exercise. Heart rate and blood pressure were assessed before exercise and during a 60min post-exercise resting period. Repeated ANOVA measures were used to determine differences between the groups. RESULTS While the control group had a significant reduction in post-exercise systolic blood pressure of up to 13.9±11.6mmHg at 40min, this phenomenon was limited among AAS users who reached a maximum of 6.2±11.5mmHg at 60min. The between groups comparison revealed significant higher post-exercise hypotension (PEH) for the control group at 30min (-12.9±14.1mmHg versus -2.9±7.6mmHg), 40min (-13.9±11.6mmHg versus -2.5±8.3mmHg), 50min (-13.9±13.9mmHg versus -5.0±7.9mmHg) and 60min (-12.5±12.8mmHg versus -6.2±11.5mmHg). There was no significant diastolic PEH in any of the groups. CONCLUSIONS This study demonstrated impaired systolic post-exercise hypotension as a new adverse effect of AAS usage.
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Gruszka K, Szczuka E, Całkosiński I, Sobiech KA, Chwałczyńska A. Thermovision analysis of surface body temperature changes after thermal stimulation treatments in healthy men. Acta Bioeng Biomech 2018; 20:79-87. [PMID: 30220714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
PURPOSE Among thermal stimulation treatments that have a beneficial effect on the human body general application of cold and various forms of massage are mentioned which can be assessed by means of thermovision analysis. The aim of the study was to evaluate changes in the distribution of surface body temperature under the influence of whole-body cryostimulation, classical massage and hot stone massage. MATERIALS AND METHODS The study was conducted on a group of 40 men aged 20-24 years. They were subjected to a cryostimulation treatment at -120 °C and -140 °C, and to heat-stimulating treatments in the form of massages. Before the treatment, blood pressure and heart rate were measured. Temperature distribution in the 12 areas of the body surface was recorded using a Thermo Vision A20M Thermo Vision Camera with Therma CAM Researcher 2.8 software. RESULTS Statistically significant differences between cryostimulation treatments in the left upper limb and the back of the trunk were found. After heat-stimulating treatments, a statistically significant increase in temperature after classic massage was observed in the lower limbs, and a similar increase in temperature was noted in the rear of the pectoral girdle and of the trunk after hot stone massage. CONCLUSIONS The thermovision analysis showed a great variation of body surface temperature depending on the body area. The higher changes in temperature, of up to 20%, were found within the upper and lower extremities in the group treated with cryostimulation. After heat-stimulating treatments, lower temperature differences, of 2-6%, were observed, the largest within the trunk and the lower limbs.
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Guerra M, F Leite-Moreira A. Relevance of intraventricular pressure gradients in left ventricular diastolic and systolic function: clinical implications. REVISTA PORTUGUESA DE CIRURGIA CARDIO-TORACICA E VASCULAR : ORGAO OFICIAL DA SOCIEDADE PORTUGUESA DE CIRURGIA CARDIO-TORACICA E VASCULAR 2018; 25:19-26. [PMID: 30317706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Indexed: 06/08/2023]
Abstract
Intraventricular pressure gradients (IVPGs) play a physiological role in normal filling and emptying of the left ventricle. Regional alterations in IVPGs might be an important factor in the characteristic changes that occur in intraventricular flow in specific cardiac disorders and may contribute to and represent an early sign of ventricular dysfunction. Diastolic IVPGs, a marker of normal ventricular filling, and systolic IVPGs, a marker of normal ventricular emptying, can be attenuated, lost entirely or even reversed when ventricular emptying is opposed by afterload elevations, after regional acute ischaemia and in failing hearts. Moreover, in patients with severe aortic valve stenosis showing IVPGs impairment, diastoIic and systolic IVPGs improved after aortic valve replacement. The importance of IVPGs in cardiac function has so far not been entirely evaluated. A proof of the prognostic role or of the ability to identify incipient ventricular dysfunction or lack of functional reserve may help clinical decisions, turning non-invasive IVPGs into useful clinical tools.
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Kang J, Hong JH, Jang MU, Choi NC, Lee JS, Kim BJ, Han MK, Bae HJ. Change in blood pressure variability in patients with acute ischemic stroke and its effect on early neurologic outcome. PLoS One 2017; 12:e0189216. [PMID: 29252991 PMCID: PMC5734725 DOI: 10.1371/journal.pone.0189216] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 11/17/2017] [Indexed: 11/19/2022] Open
Abstract
Background How short-term blood pressure variability (BPV) is affected in the acute stage of ischemic stroke and whether BPV is associated with early neurologic outcomes remains unclear. Methods Patients who admitted for ischemic stroke within 24 h of symptom onset were consecutively identified between January 2010 and January 2015. BP profiles measured in real-time were summarized into short-term, 24-h time intervals, based on standard deviation (SD) and mean of systolic BP (SBPSD) during the first 3 days. The primary outcome was daily assessment of early neurological deterioration (END). The associations between short-term SBPSD values and the secular trend for primary outcome were examined. Results A total of 2,545 subjects (mean age, 67.1 ± 13.5 years old and median baseline National Institutes of Health Stroke Scale score, 3) arrived at the hospital an average of 6.1 ± 6.6 h after symptom onset. SBPSD values at day 1 (SD#D1), SD#D2, and SD#D3 were 14.4 ± 5.0, 12.5 ± 4.5, and 12.2 ± 4.6 mmHg, respectively. Multivariable analyses showed that SD#D2 was independently associated with onset of END at day 2 (adjusted odds ratio, 1.08; 95% confidence interval, 1.03–1.13), and SD#D3 was independently associated with END#D3 (1.07, 1.01–1.14), with adjustments for predetermined covariates, SBPmean, and interactions with daily SBPSD. Conclusion Short-term BPV changed and stabilized from the first day of ischemic stroke. Daily high BPV may be associated with neurological deterioration independent of BPV on the previous day.
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de Almeida MMS, Guimarães RA, Jardim PCBV, Sousa ALL, de Souza MM. Association between arterial hypertension and nutritional status in adolescents from Goiânia, Goiás, Brazil. PLoS One 2017; 12:e0188782. [PMID: 29253900 PMCID: PMC5734768 DOI: 10.1371/journal.pone.0188782] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 11/13/2017] [Indexed: 02/06/2023] Open
Abstract
INTRODUCTION Adolescents are a population with unique lifestyle challenges, including physical inactivity, inadequate nutrition, and obesity, all of which increase the risk of developing hypertension (HTN). The objective of this study has been to estimate the prevalence of factors associated with hypertension in adolescents in the city of Goiânia City, Central Brazil. METHODS Between 2013and2014, a cross-sectional population study on cardiovascular risk in adolescents, was conducted with the participation of 1,586 adolescents in 108 classes at 36 schools (public and private) in Goiânia city. All of the adolescents were interviewed to establish their sociodemographic and behavioral characteristics related to hypertension and nutritional status. Anthropometric and blood pressure data were collected following a protocol. A Poisson regression, stratified by gender, was used to verify the factors associated with HTN. RESULTS In this mixed-gender group of 1,586 students, the prevalence of HTN was 6.2% (95% CI: 4.6-8.2%) in girls and 14.0% (95% CI: 10.2-18.8%) in boys-about twice as high in boys as in girls (p <0.001). Obesity was independently associated with HTN in both genders. Being overweight was a risk factor for HTN. In addition, there was a positive correlation between the SBP/SBP percentile and the BMI Z-score/Nutritional status (NS)in both genders. A high prevalence of physical inactivity was also observed in the adolescents investigated, especially in the girls. On the other hand, more boys than girls were found to be obese. CONCLUSION The results of this investigation revealed the need for strategies to prevent and control HTN and its risk factors, especially in Brazil's schools. In addition to the constant surveillance of HTN prevalence and risk factors (in particular, being overweight or obese), information should be distributed to promote beneficial health behaviors among adolescents.
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Braig M, Leupold J, Menza M, Russe M, Ko CW, Hennig J, von Elverfeldt D. Preclinical 4D-flow magnetic resonance phase contrast imaging of the murine aortic arch. PLoS One 2017; 12:e0187596. [PMID: 29117252 PMCID: PMC5678712 DOI: 10.1371/journal.pone.0187596] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 10/23/2017] [Indexed: 12/31/2022] Open
Abstract
PURPOSE Cardiovascular diseases remain the number one death cause worldwide. Preclinical 4D flow phase contrast magnetic resonance imaging can provide substantial insights in the analysis of aortic pathophysiologies in various animal models. These insights may allow a better understanding of pathophysiologies, therapy monitoring, and can possibly be translated to humans. This study provides a framework to acquire the velocity field within the aortic arch. It analyses important flow values at different locations within the aortic arch. Imaging parameters with high temporal and spatial resolution are provided, that still allow combining this time-consuming method with other necessary imaging-protocols. METHODS A new setup was established where a prospectively gated 4D phase contrast sequence is combined with a highly sensitive cryogenic coil on a preclinical magnetic resonance scanner. The sequence was redesigned to maintain a close to steady state condition of the longitudinal magnetization and hence to overcome steady state artifacts. Imaging parameters were optimized to provide high spatial and temporal resolution. Pathline visualizations were generated from the acquired velocity data in order to display complex flow patterns. RESULTS Our setup allows data acquisition with at least two times the rate than that of previous publications based on Cartesian encoding, at an improved image quality. The "steady state" sequence reduces observed artifacts and provides uniform image intensity over the heart cycle. This made possible quantification of blood speed and wall shear stress (WSS) within the aorta and its branches. The highest velocities were observed in the ascending aorta with 137.5 ± 8 cm/s. Peak velocity values in the Brachiocephalic trunk were 57 ± 12 cm/s. Quantification showed that the peak flow occurs around 20 ms post R-wave in the ascending aorta. The highest mean axial wall shear stress was observed in the analysis plane between the left common carotid artery (LCCA) and the left subclavian artery. A stable image quality allows visualizing complex flow patterns by means of streamlines and for the first time, to the best of our knowledge, pathline visualizations from 4D flow MRI in mice. CONCLUSION The described setup allows analyzing pathophysiologies in mouse models of cardiovascular diseases in the aorta and its branches with better image quality and higher spatial and temporal resolution than previous Cartesian publications. Pathlines provide an advanced analysis of complex flow patterns in the murine aorta. An imaging protocol is provided that offers the possibility to acquire the aortic arch at sufficiently high resolution in less than one hour. This allows the combination of the flow assessment with other multifunctional imaging protocols.
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de Goede AA, Loef BG, Reidinga AC, Schaafsma A. Fluid Resuscitation in Septic Patients Improves Systolic but not Diastolic Middle Cerebral Artery Flow Velocity. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:2591-2600. [PMID: 28779955 DOI: 10.1016/j.ultrasmedbio.2017.06.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 06/16/2017] [Accepted: 06/23/2017] [Indexed: 06/07/2023]
Abstract
To investigate the effects of fluid resuscitation on cerebral hemodynamics in sepsis, the following set of transcranial Doppler (TCD) parameters was used: maximal change in flow velocity (FV) during stroke onset (acc), maximal FV during first (sys1) or second (sys2) phase of systole and mean diastolic FV (dias@560). We aim to evaluate changes in cerebral hemodynamics that result from (i) sepsis and (ii) adequate fluid resuscitation in critically ill septic patients. In the majority of 16 septic patients sys2 was initially absent but reappeared during the period of fluid resuscitation; whereas sys2 absence was never seen in healthy controls. Second, adequate fluid resuscitation resulted in a significant increase of the systolic FV components (acc, sys1, sys2 and systolic blood pressure); whereas the diastolic components (dias@560 and diastolic blood pressure) remained unchanged. Sys2 absence and reappearance in sepsis suggests that TCD could become a non-invasive alternative for hemodynamic monitoring.
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Yaseri M, Afarideh M, Hosseini M, Yousefifard M, Rafei A, Koohpayehzadeh J, Asgari F, Etemad K, Gouya MM, Noshad S, Bagheri M, Ataei N. Zero and Five End-Digit Preference and Blood Pressure Quality of Care Revisited. ARCHIVES OF IRANIAN MEDICINE 2017; 20:633-639. [PMID: 29137464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
BACKGROUND To determine the rate of zero and five end-digit preference (EDP) for systolic and diastolic blood pressures (SBP and DBP, respectively) and risk factors amongst a representative sample of Iranian adults in the year 2011. METHODS Data gathered from 7997 Iranian adults aged 25-70 were extracted from the database of the sixth Survey of Surveillance of Risk Factors of Non-communicable Diseases, which surveyed a total of 11,864 individuals aged 6 to 70 years. Multilevel multiple logistic regression was used to identify the independent factors associated with zero or five EDP. RESULTS The prevalence of three serial zero or five EDP for SBP and DBP were 18.5% (95% CI: 11.3%-25.7%). SBP ≥140 mmHg (OR = 0.78; 95% CI: 0.65-0.95), DBP ≥90 mmHg (OR = 0.71; 95% CI: 0.58-0.88), and a positive family history of diabetes (OR = 0.77; 95% CI: 0.66-0.9) were found as protective factors against zero or five EDP in blood pressure recording the male gender (OR = 1.18; 95% CI: 1.04-1.35) was found to be its independent risk factor. CONCLUSION Sex, SBP, DBP and family history of diabetes were found to be the main independent determinants of EDP in our country which underscores the importance of assessing the many patient-related factors in the studies involving EDP as part of BP monitoring in public health care.
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Roberts TA, Price AN, Jackson LH, Taylor V, David AL, Lythgoe MF, Stuckey DJ. Direct comparison of high-temporal-resolution CINE MRI with Doppler ultrasound for assessment of diastolic dysfunction in mice. NMR IN BIOMEDICINE 2017; 30:e3763. [PMID: 28643891 PMCID: PMC5638074 DOI: 10.1002/nbm.3763] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 05/17/2017] [Accepted: 05/18/2017] [Indexed: 08/24/2023]
Abstract
Diastolic dysfunction is a sensitive early indicator of heart failure and can provide additional data to conventional measures of systolic function. Transmitral Doppler ultrasound, which measures the one-dimensional flow of blood through the mitral valve, is currently the preferred method for the measurement of diastolic function, but the measurement of the left ventricular volume changes using high-temporal-resolution cinematic magnetic resonance imaging (CINE MRI) is an alternative approach which is emerging as a potentially more robust and user-independent technique. Here, we investigated the performance of high-temporal-resolution CINE MRI and compared it with ultrasound for the detection of diastolic dysfunction in a mouse model of myocardial infarction. An in-house, high-temporal-resolution, retrospectively gated CINE sequence was developed with a temporal resolution of 1 ms. Diastolic function in mice was assessed using a custom-made, open-source reconstruction package. Early (E) and late (A) left ventricular filling phases were easily identifiable, and these measurements were compared directly with high-frequency, pulsed-wave, Doppler ultrasound measurements of mitral valve inflow. A repeatability study established that high-temporal-resolution CINE MRI and Doppler ultrasound showed comparable accuracy when measuring E/A in normal control mice. However, when applied in a mouse model of myocardial infarction, high-temporal-resolution CINE MRI indicated diastolic heart failure (E/A = 0.94 ± 0.11), whereas ultrasound falsely detected normal cardiac function (E/A = 1.21 ± 0.11). The addition of high-temporal-resolution CINE MRI to preclinical imaging studies enhances the library of sequences available to cardiac researchers and potentially identifies diastolic heart failure early in disease progression.
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Carreira PE, Carmona L, Joven BE, Loza E, Andreu JL, Riemekasten G, Vettori S, Allanore Y, Balbir-Gurman A, Airò P, Walker UA, Damjanov N, Ananieva LP, Rednic S, Czirják L, Distler O, Farge D, Hesselstrand R, Corrado A, Caramaschi P, Tikly M, Matucci-Cerinic M. Clinical determinants of elevated systolic pulmonary artery pressure measured by transthoracic Doppler echocardiography in early systemic sclerosis. Clin Exp Rheumatol 2017; 35 Suppl 106:114-121. [PMID: 28664832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 10/26/2016] [Indexed: 06/07/2023]
Abstract
OBJECTIVES To explore the prevalence and clinical associations of elevated systolic pulmonary artery pressure (sPAP), measured by Transthoracic Doppler-echocardiography (TTE) in patients with early systemic sclerosis (SSc). METHODS A cross-sectional analysis of the prospective EULAR Scleroderma Trial and Research (EUSTAR) database was performed. SSc patients with <3 years from the first non-Raynaud's phenomenon (RP) symptom at baseline EUSTAR visit, were selected. Elevated sPAP was defined as sPAP>40 mmHg on baseline TTE. First visit SSc related variables, including disease subsets, antibodies and visceral involvement, were examined. RESULTS From 1,188 patients, 81% were women. Mean (SD) age at first non-RP symptom was 50 (14) years, 55% had limited cutaneous SSc (lcSSc) and 42% active disease. Elevated sPAP was found in 17% of patients, both lcSSc and diffuse cutaneous SSc (dcSSc). In lcSSc, older age at first non-RP symptom, ACA positivity, joint contractures, restrictive defect and lower DLCO, were independently associated with elevated sPAP. In dcSSc, older age at first non-RP symptom, longer time between RP onset and first non-RP symptom, digital ulcers, cardiac blocks, and proteinuria were associated with elevated sPAP. CONCLUSIONS The prevalence of elevated sPAP on TTE in early SSc patients is considerable. Association with cardiac, lung and renal involvement suggests that, although some patients might have pulmonary arterial hypertension, others may present pulmonary hypertension secondary to lung or heart involvement. Our findings emphasize the need to consider right heart catheterisation in selected early SSc patients with PH suspicion, to clearly determine the cause of PH.
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Sankaranarayanan R, Kistamás K, Greensmith DJ, Venetucci LA, Eisner DA. Systolic [Ca 2+ ] i regulates diastolic levels in rat ventricular myocytes. J Physiol 2017; 595:5545-5555. [PMID: 28617952 PMCID: PMC5556151 DOI: 10.1113/jp274366] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 06/13/2017] [Indexed: 11/30/2022] Open
Abstract
KEY POINTS For the heart to function as a pump, intracellular calcium concentration ([Ca2+ ]i ) must increase during systole to activate contraction and then fall, during diastole, to allow the myofilaments to relax and the heart to refill with blood. The present study investigates the control of diastolic [Ca2+ ]i in rat ventricular myocytes. We show that diastolic [Ca2+ ]i is increased by manoeuvres that decrease sarcoplasmic reticulum function. This is accompanied by a decrease of systolic [Ca2+ ]i such that the time-averaged [Ca2+ ]i remains constant. We report that diastolic [Ca2+ ]i is controlled by the balance between Ca2+ entry and Ca2+ efflux during systole. The results of the present study identify a novel mechanism by which changes of the amplitude of the systolic Ca transient control diastolic [Ca2+ ]i . ABSTRACT The intracellular Ca concentration ([Ca2+ ]i ) must be sufficently low in diastole so that the ventricle is relaxed and can refill with blood. Interference with this will impair relaxation. The factors responsible for regulation of diastolic [Ca2+ ]i , in particular the relative roles of the sarcoplasmic reticulum (SR) and surface membrane, are unclear. We investigated the effects on diastolic [Ca2+ ]i that result from the changes of Ca cycling known to occur in heart failure. Experiments were performed using Fluo-3 in voltage clamped rat ventricular myocytes. Increasing stimulation frequency increased diastolic [Ca2+ ]i . This increase of [Ca2+ ]i was larger when SR function was impaired either by making the ryanodine receptor leaky (with caffeine or ryanodine) or by decreasing sarco/endoplasmic reticulum Ca-ATPase activity with thapsigargin. The increase of diastolic [Ca2+ ]i produced by interfering with the SR was accompanied by a decrease of the amplitude of the systolic Ca transient, such that there was no change of time-averaged [Ca2+ ]i . Time-averaged [Ca2+ ]i was increased by β-adrenergic stimulation with isoprenaline and increased in a saturating manner with increased stimulation frequency; average [Ca2+ ]i was a linear function of Ca entry per unit time. Diastolic and time-averaged [Ca2+ ]i were decreased by decreasing the L-type Ca current (with 50 μm cadmium chloride). We conclude that diastolic [Ca2+ ]i is controlled by the balance between Ca entry and efflux during systole. Furthermore, manoeuvres that decrease the amplitude of the Ca transient (without decreasing Ca influx) will therefore increase diastolic [Ca2+ ]i . This identifies a novel mechanism by which changes of the amplitude of the systolic Ca transient control diastolic [Ca2+ ]i .
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Yeh HH, Rabkin SW, Grecov D. Hemodynamic assessments of the ascending thoracic aortic aneurysm using fluid-structure interaction approach. Med Biol Eng Comput 2017; 56:435-451. [PMID: 28798988 DOI: 10.1007/s11517-017-1693-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 07/18/2017] [Indexed: 12/24/2022]
Abstract
Current assessment and management of ascending thoracic aortic aneurysm (ATAA) rely heavily on the diameter of the ATAA and blood pressure rather than biomechanical and hemodynamic parameters such as arterial wall deformation or wall shear stress. The objective of the current study was to develop an accurate computational method for modeling the mechanical responses of the ATAA to provide additional information in patient evaluations. Fully coupled fluid structure interaction simulations were conducted using data from cases with ATAA with measured geometrical parameters in order to evaluate and analyze the change in biomechanical responses under normotensive and hypertensive conditions. Anisotropic hyperelastic material property estimates were applied to the ATAA data which represented three different geometrical configurations of ATAAs. The resulting analysis showed significant variations in maximum wall shear stress despite minimal differences in flow velocity between two blood pressure conditions. Additionally, the three different ATAA conditions identified different aortic expansions that were not uniform under pulsatile pressure. The elevated wall stress with hypertension was also geometry-dependent. The developed models suggest that ATTA cases have unique characteristic in biomechanical and hemodynamic evaluations that can be useful in risk management.
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Buxi D, Hermeling E, Mercuri M, Beutel F, van der Westen RG, Torfs T, Redoute JM, Yuce MR. Systolic Time Interval Estimation Using Continuous Wave Radar With On-Body Antennas. IEEE J Biomed Health Inform 2017; 22:129-139. [PMID: 28749359 DOI: 10.1109/jbhi.2017.2731790] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The estimation of systolic time intervals (STIs) is done using continuous wave (CW) radar at 2.45 GHz with an on-body antenna. MOTIVATION In the state of the art, typically bioimpedance, heart sounds and/or ultrasound are used to measure STIs. All three methods suffer from insufficient accuracy of STI estimation due to various reasons. CW radar is investigated for its ability to overcome the deficiencies in the state of the art. METHODS Ten healthy male subjects aged 25-45 were asked to lie down at a 30 incline. Recordings of 60 s were taken without breathing and with paced breathing. Heart sounds, electrocardiogram, respiration, and impedance cardiogram were measured simultaneously as reference. The radar antennas were placed at two positions on the chest. The antennas were placed directly on the body as well as with cotton textile in between. The beat to beat STIs have been determined from the reference signals as well as CW radar signals. RESULTS The results indicate that CW radar can be used to estimate STIs in ambulatory monitoring. SIGNIFICANCE The results pave way to a potentially more compact method of estimating STIs, which can be integrated into a wearable device.
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Atef M. A feature exploration methodology for learning based cuffless blood pressure measurement using photoplethysmography. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2016:6385-6388. [PMID: 28269709 DOI: 10.1109/embc.2016.7592189] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In this work, we propose a feature exploration method for learning-based cuffless blood pressure measurement. More specifically, to efficiently explore a large feature space from the photoplethysmography signal, we have applied several analytical techniques, including random error elimination, adaptive outlier removal, maximum information coefficient and Pearson's correlation coefficient based feature assessment methods. We evaluate fifty-seven possible feature candidates and propose three separate feature sets with each containing eleven features to predict the systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure (MBP), respectively. From our experimental results on a realistic dataset, this work achieves 4.77±7.68, 3.67±5.69 and 3.85±5.87 mmHg prediction accuracy for SBP, DBP and MBP. In summary, using the proposed light-weight features, the proposed predictors can successfully achieve a Grade A in two standards proposed by the American National Standards of the Association for the Advancement of Medical Instrumentation (AAMI) and British Hypertension Society (BHS).
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Vollmann D, Hansen C, Lüthje L, Breithardt OA. [Malignant bileaflet mitral valve prolapse syndrome in otherwise idiopathic ventricular fibrillation]. Herzschrittmacherther Elektrophysiol 2017; 28:232-235. [PMID: 28477226 DOI: 10.1007/s00399-017-0504-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 04/10/2017] [Indexed: 06/07/2023]
Abstract
A 32-year-old, otherwise healthy woman was admitted after successful out-of-hospital resuscitation due to ventricular fibrillation. Established cardiac, pulmonary, metabolic, and toxicological causes were excluded. However, persisting (biphasic) negative T waves in the inferior ECG leads and premature ventricular contractions (PVC) were noted. PVC morphology indicated a focus alternating between the posterior papillary muscle/the left posterior fascicle and the left ventricular outflow tract region/anterior papillary muscle. Echocardiography revealed a bileaflet mitral prolapse with mild mitral valve regurgitation. This case is a typical presentation of the recently described malignant bileaflet mitral valve prolapse syndrome. The patient was discharged without overt neurological deficit after implantation of a cardioverter-defibrillator.
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Kanegae H, Oikawa T, Okawara Y, Hoshide S, Kario K. Which blood pressure measurement, systolic or diastolic, better predicts future hypertension in normotensive young adults? J Clin Hypertens (Greenwich) 2017; 19:603-610. [PMID: 28444926 PMCID: PMC8030768 DOI: 10.1111/jch.13015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/01/2017] [Accepted: 02/13/2017] [Indexed: 11/30/2022]
Abstract
The impact of age-related differences in blood pressure (BP) components on new-onset hypertension is not known. A follow-up examination of 93 303 normotensive individuals (mean age 41.1 years) who underwent a health checkup in 2005 was conducted every year for 8 years. The primary end point was new-onset hypertension (systolic BP [SBP]/diastolic BP [DBP] ≥140/90 mm Hg and/or the initiation of antihypertensive medications with self-reported hypertension). During the mean 4.9 years of follow-up, 14 590 subjects developed hypertension. The impact of DBP on the risk of developing hypertension compared with optimal BP (SBP <120 mm Hg and DBP <80 mm Hg) was significantly greater than that of SBP in subjects younger than 50 years (hazard ratios, 17.5 for isolated diastolic high-normal vs 10.5 for isolated systolic high-normal [P<.001]; 8.0 for isolated diastolic normal vs 4.1 for isolated systolic normal [P<.001]). Among the subjects 50 years and older, the corresponding effects of DBP and SBP were similar. Regarding the risk of new-onset hypertension, high DBP is more important than SBP in younger adults (<50 years) with normal or high-normal BP.
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Lo Q, Hee L, Batumalai V, Allman C, MacDonald P, Lonergan D, Delaney GP, Thomas L. Strain Imaging Detects Dose-Dependent Segmental Cardiac Dysfunction in the Acute Phase After Breast Irradiation. Int J Radiat Oncol Biol Phys 2017; 99:182-190. [PMID: 28816145 DOI: 10.1016/j.ijrobp.2017.05.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 05/02/2017] [Accepted: 05/18/2017] [Indexed: 02/06/2023]
Abstract
PURPOSE We examined the utility of echocardiographic 2-dimensional speckle tracking strain imaging (SI) for the evaluation of segmental myocardial dysfunction before and after radiation therapy (RT) and the relationship to dose exposure. METHODS AND MATERIALS We prospectively recruited 40 women with left-sided breast cancer, undergoing only adjuvant RT to the left chest. Comparisons of traditional echocardiographic parameters and SI parameters at baseline and 6 weeks after RT were analyzed. Regional strain and strain rate (SR) parameters were obtained from all 18 left ventricular segments. The correlation of change in strain parameters with segmental radiation dose was examined. RESULTS We observed a significant reduction in global and segmental systolic strain parameters at 6 weeks after RT compared with baseline, with the largest decrement in the apical segments; this corresponded with the segments receiving the highest radiation dose exposure (apical peak systolic strain of -21.21% ± 3.49% before RT vs -18.69% ± 3.34% after RT, percentage change of 11.88%, P=.002; apical peak systolic SR of -1.17 ± 0.24 s-1 before RT vs -1.04 ± 0.19 s-1 after RT, percentage change of 11.11%, P=.008). There was a modest correlation between the apical segment systolic strain reduction and radiation dose exposure (apical segment Δ change and apical radiation dose, r=0.345, P=.031; apical segment percentage change and apical radiation dose, r=0.346, P=.031). A significant reduction in early diastolic SR was observed in the apical segments after treatment compared with baseline (apical early diastolic SR, 1.54 ± 0.45 s-1 before RT vs 1.35 ± 0.33 after RT s-1; percentage change, 12.34%; P=.034). CONCLUSIONS Two-dimensional SI detected dose-related regional myocardial dysfunction in the acute phase after RT in chemotherapy-naive left-sided breast cancer patients. Although the long-term effects remain unknown, this imaging modality may have a potential role in the evaluation of irradiation-related cardiotoxicity.
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Ahn YM, Choi YH, Yoon JJ, Lee YJ, Cho KW, Kang DG, Lee HS. Oleanolic acid modulates the renin-angiotensin system and cardiac natriuretic hormone concomitantly with volume and pressure balance in rats. Eur J Pharmacol 2017; 809:231-241. [PMID: 28514645 DOI: 10.1016/j.ejphar.2017.05.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 05/12/2017] [Accepted: 05/12/2017] [Indexed: 01/13/2023]
Abstract
Oleanolic acid is known to possess beneficial effects on the regulation of the cardiovascular homeostasis. However, the exact nature of the role of oleanolic acid on the regulation of body fluid balance and blood pressure homeostasis and its mechanisms involved are not well defined. Experiments were performed to identify the effects of oleanolic acid on the renin-angiotensin system and cardiac natriuretic hormone (ANP) system, and also renal function and blood pressure in normotensive and renovascular hypertensive rats. The change in the plasma levels of hormones and the expressions of renin, angiotensin II receptors, ANP, natriuretic peptide receptor-C, M2 muscarinic receptor and GIRK4 were determined in the kidney, heart and aorta. Oleanolic acid was administered orally for 1 or 3 weeks. Here, we found that oleanolic acid suppressed plasma levels of renin activity and aldosterone and intrarenal levels of renin and angiotensin II type 1 receptor expression and increased angiotensin II type 2 receptor in normotensive and hypertensive rats. Also, oleanolic acid increased plasma levels of ANP. Further, oleanolic acid suppressed angiotensin II type 1 receptor and natriuretic peptide receptor-C expression and increased angiotensin II type 2 receptor and ANP expression in the heart and aorta. Along with these changes, oleanolic acid accentuated urinary volume, electrolyte excretion and glomerular filtration rate in normotensive rats and suppressed arterial blood pressure in hypertensive rats. These findings suggest that beneficial effects of oleanolic acid on the cardiorenal system are closely associated with its roles on the renin-angiotensin system and cardiac natriuretic hormone system.
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Parikh JD, Hollingsworth KG, Wallace D, Blamire AM, MacGowan GA. Left ventricular functional, structural and energetic effects of normal aging: Comparison with hypertension. PLoS One 2017; 12:e0177404. [PMID: 28493996 PMCID: PMC5426746 DOI: 10.1371/journal.pone.0177404] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/26/2017] [Indexed: 01/19/2023] Open
Abstract
Objectives Both aging and hypertension are significant risk factors for heart failure in the elderly. The purpose of this study was to determine how aging, with and without hypertension, affects left ventricular function. Methods Cross-sectional study of magnetic resonance imaging and 31P spectroscopy-based measurements of left ventricular structure, global function, strains, pulse wave velocity, high energy phosphate metabolism in 48 normal subjects and 40 treated hypertensive patients (though no other cardiovascular disease or diabetes) stratified into 3 age deciles from 50–79 years. Results Normal aging was associated with significant increases in systolic blood pressure, vascular stiffness, torsion, and impaired diastolic function (all P<0.05). Age-matched hypertension exacerbated the effects of aging on systolic pressure, and diastolic function. Hypertension alone, and not aging, was associated with increased left ventricular mass index, reduced energetic reserve, reduced longitudinal shortening and increased endocardial circumferential shortening (all P<0.05). Multiple linear regression analysis showed that these unique hypertensive features were significantly related to systolic blood pressure (P<0.05). Conclusions 1) Hypertension adds to the age-related changes in systolic blood pressure and diastolic function; 2) hypertension is uniquely associated with changes in several aspects of left ventricular structure, function, systolic strains, and energetics; and 3) these uniquely hypertensive-associated parameters are related to the level of systolic blood pressure and so are potentially modifiable.
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Spannella F, Giulietti F, Fedecostante M, Ricci M, Balietti P, Cocci G, Landi L, Bonfigli AR, Boemi M, Espinosa E, Sarzani R. Interarm blood pressure differences predict target organ damage in type 2 diabetes. J Clin Hypertens (Greenwich) 2017; 19:472-478. [PMID: 28026096 PMCID: PMC8031307 DOI: 10.1111/jch.12963] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 11/07/2016] [Accepted: 11/11/2016] [Indexed: 11/29/2022]
Abstract
Patients with type 2 diabetes mellitus are at high risk for atherosclerotic disease, and proper blood pressure measurement is mandatory. The authors examined the prevalence of an interarm difference (IAD) in blood pressure and its association with cardiovascular risk factors and organ damage (nephropathy, retinopathy, left ventricular hypertrophy, and vascular damage) in a large diabetic population. A total of 800 consecutive patients with type 2 diabetes mellitus were evaluated with an automated simultaneous bilateral device (men: 422 [52.8%]; mean age: 68.1±12.2 years). Diabetic patients with systolic IAD ≥5 and systolic IAD ≥10 mm Hg showed an increased risk of having vascular damage (adjusted odds ratios: 1.73 and 2.49, respectively) and higher pulse pressure. IAD is highly prevalent in patients with diabetes, is associated with vascular damage, even for IAD ≥5 mm Hg, and should be accurately obtained to avoid underdiagnosis and undertreatment of hypertension.
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Fassina L, Rozzi G, Rossi S, Scacchi S, Galetti M, Lo Muzio FP, Del Bianco F, Colli Franzone P, Petrilli G, Faggian G, Miragoli M. Cardiac kinematic parameters computed from video of in situ beating heart. Sci Rep 2017; 7:46143. [PMID: 28397830 PMCID: PMC5387404 DOI: 10.1038/srep46143,10.1038/srep46143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/13/2017] [Indexed: 04/01/2024] Open
Abstract
Mechanical function of the heart during open-chest cardiac surgery is exclusively monitored by echocardiographic techniques. However, little is known about local kinematics, particularly for the reperfused regions after ischemic events. We report a novel imaging modality, which extracts local and global kinematic parameters from videos of in situ beating hearts, displaying live video cardiograms of the contraction events. A custom algorithm tracked the movement of a video marker positioned ad hoc onto a selected area and analyzed, during the entire recording, the contraction trajectory, displacement, velocity, acceleration, kinetic energy and force. Moreover, global epicardial velocity and vorticity were analyzed by means of Particle Image Velocimetry tool. We validated our new technique by i) computational modeling of cardiac ischemia, ii) video recordings of ischemic/reperfused rat hearts, iii) videos of beating human hearts before and after coronary artery bypass graft, and iv) local Frank-Starling effect. In rats, we observed a decrement of kinematic parameters during acute ischemia and a significant increment in the same region after reperfusion. We detected similar behavior in operated patients. This modality adds important functional values on cardiac outcomes and supports the intervention in a contact-free and non-invasive mode. Moreover, it does not require particular operator-dependent skills.
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Prot V, Skallerud B. Contributions of prestrains, hyperelasticity, and muscle fiber activation on mitral valve systolic performance. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33:e2806. [PMID: 27274001 DOI: 10.1002/cnm.2806] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 04/01/2016] [Accepted: 05/28/2016] [Indexed: 06/06/2023]
Abstract
The present study addresses the contributions of prestrains and muscle fiber activation to the global response of the mitral valve during systole. A finite element model of a porcine mitral valve is created using anatomical measurements and 3D echocardiographic recordings. The passive behavior of the leaflets is modeled using a transversely isotropic hyperelastic constitutive model, and we assume orthotropic muscle activations in the anterior leaflet. A simple approach to incorporate prestrains in the mitral valve apparatus is used by expanding the mitral annulus before applying the ventricular pressure to the mitral leaflets. Several finite element analyses are run with or without muscle activation and with or without prestrains. The analysis results are compared at peak systole with the echocardiograpic recordings. The case where prestrains and activation are accounted for simultaneously is the most efficient to approach the physiological flat shape of the closed valve observed in the echocardiograpic measurements. These results suggest that the active components present in the mitral leaflets and the presence of prestrains contribute to the physiological deformations of the mitral valve at peak systole and that material models based on in vitro mechanical testing are not sufficient for numerical studies of the mitral apparatus. Copyright © 2016 John Wiley & Sons, Ltd.
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