First Author: Wei Kong
All Authors: Kong W, Huang J, Rollins DL, Ideker RE, Smith WM
Journal Title: Physiological measurement
Abstract: We have developed an eight-channel telemetry system for studying experimental models of chronic cardiovascular disease. The system is an extension of a previous device that has been miniaturized, reduced in power consumption and provided with increased functionality. We added sensors for ventricular dimension, and coronary artery blood flow and arterial blood pressure that are suitable for use with the system. The telemetry system consists of a front end, a backpack and a host PC. The front end is a watertight stainless steel case with all sensor electronics sealed inside; it acquires dimension, flow, pressure and five cardiac electrograms from selected locations on the heart. The backpack includes a control unit, Bluetooth radio, and batteries. The control unit digitizes eight channels of data from the front end and forwards them to the host PC via Bluetooth link. The host PC has a receiving Bluetooth radio and Labview programs to store and display data. The whole system was successfully tested on the bench and in an animal model. This telemetry system will greatly enhance the ability to study events leading to spontaneous sudden cardiac arrest.
Better Clinical Outcome For Rehospitalization Heart Failure Patients With Reduced Left Ventricular Function in Mode of Sudden Cardiac Death
I'm Not Sure We Had A Choice?: Decision Quality and The Use of Cardiac Implantable Electronic Devices In Older Adults With Cognitive Impairment
Authors: Jiang J, Ding X, Jiang W, Xu J, Fang Y, Teng J
Abstract: To evaluate the long-term outcome of acute kidney injury (AKI) during hospitalization after cardiac surgery.1 770 patients underwent cardiac surgery in Fudan University Zhongshan Hospital from April 2009 to February 2011 were enrolled. Based on the Kidney Disease: Improving Global Outcomes (KDIGO) guideline of AKI, the patients were divided into the AKI and the non-AKI groups, and followed up for 2 years. The 2-year survival rate and incidence of the advanced chronic kidney disease (CKD) was compared between the two groups.Factors influencing the 2-year survival rate and incidence of the advanced CKD were also analyzed.Among all the patients, 715 (40.4%) of them were developed AKT. (1) The 2-year survival rate of the AKI group was lower than that of the non-AKI group (83.2% vs 93.6%;P < 0.05). Compared with the non-AKI group, AKI group had an increased risk for death with the hazard ratio of 1.710 (95%CI 1.250-2.340). COX regression analysis showed that AKI was an independent factor for death with the risk intensity just less than diabetes and chronic cardiac insufficiency. The advanced age, the preoperative history of chronic cardiac insufficiency and the time of staying in ICU also significantly increased the risk of death. (2) Compared with patients without AKI (0.2%), the incidence of the 2-year of advanced CKD was higher in patients with AKI (6.7%;P < 0.05) with an hazard ratio of 31.220 (95%CI 7.550-129.110). COX regression analysis showed that AKI was still the independent risk factor for advanced CKD after adjustment of other factors.In addition, diabetes, the time of the cardiopulmonary bypass and the time of staying in ICU were also associated with the risk for the advanced CKD.AKI is common after cardiac surgery, which was associated with a decrease in the 2-year survival rate and an increase in the incidence of advanced CKD of patients, which emphasized the importance of prevention and treatment of AKI, and close follow-up of renal function for the improvement of patient long-term prognosis.
Authors: Saho T, Onishi H
Abstract: In this study, we evaluated the hemodynamics of carotid artery models with carotid bulbs of various sizes using computational fluid dynamics (CFD) and the Fluent CFD software. The oscillatory shear index (OSI) and flow velocity distribution were evaluated in carotid models without a carotid bulb and with carotid bulbs of known geometry (major axis of 10, 11, 12, 13, and 14 mm; carotid bifurcation angle of 50°). Furthermore, the diameters of the common carotid artery, the external carotid artery, and the internal carotid artery were defined as 7.2, 4.0, and 4.5 mm, respectively. The accuracy of the CFD analysis in this study was verified using a flow phantom and measuring velocities with phase-contrast cine magnetic resonance imaging. The CFD parameters were defined as follows: rigid and no-slip walls, pulsatile flow, and 0 Pa of peripheral pressure. The OSI in the carotid bulb tended to show a high value during the expansion of the carotid bulb (maximum and minimum OSI: 0.11 ± 0.08 at d bulb: 14 mm; 0.0013 ± 0.0011 at no bulb), and the region of high OSI expanded with the expansion of the carotid bulb. The flow separated near the carotid bulb, and the flow deceleration expanded downstream as the size of the bulb increased. These findings suggest that the size of the carotid bulbs contributed to the OSI because the larger bulbs exhibited higher OSI values. The relation between the OSI and the carotid bulb size could serve as a risk indicator for atherosclerosis.
Authors: Nagamori T, Yoshida Y, Takahashi H, Oka H, Kajihama A, Nakau K, Sugimoto M, Minami-Hori M, Azuma H
Abstract: Juvenile-onset systemic sclerosis (jSSc) is a rare condition, having unique characteristic features compared to adult-onset SSc. Although cardiac involvement (CI) is known as a leading cause of mortality overall in SSc, the importance of CI in jSSc has not been emphasized. Here we present a 13-year-old female with jSSc overlapped with dermatomyositis (DM) complicated CI. She developed skin thickness and induration, Raynaud's phenomenon, digital pitting scars in fingertips, and skeletal myositis. Oral prednisolone and pulse methotrexate treatment led to the improvement of skin findings; however two weeks after the initiation she suddenly presented with muscle pain and dyspnea within a few days. Cardiac investigations then showed pericardiac effusion and diastolic dysfunction due to significant biventricular hypertrophy causing heart failure. As pericardiac effusion and exacerbation of skeletal myositis were evident, steroid pulse therapy was initiated. Unexpectedly, not only the myositis but also the CI including diastolic dysfunction was improved. She thereafter followed a favorable clinical course without reactivation of the CI or cardiac fibrosis. As a conclusion, close attention to CI must be paid in jSSc patients, especially when skeletal muscle involvement is evident and immunosuppressive therapy may be effective for CI in jSSc in cases where it occurs abruptly.
Authors: Koshino K, Fukushima K, Fukumoto M, Sasaki K, Moriguchi T, Hori Y, Zeniya T, Nishimura Y, Kiso K, Iida H
Abstract: Attenuation correction of a single photon emission computed tomography (SPECT) image is possible using computed tomography (CT)-based attenuation maps with hybrid SPECT/CT. CT attenuation maps acquired during breath holding can be misaligned with SPECT, generating artifacts in the reconstructed images. The purpose of this study was to investigate the effects of respiratory phase during breath-hold CT acquisition on attenuation correction of cardiac SPECT imaging.A series of 201Tl-emission and 99mTc-based transmission computed tomography (TCT) scans was carried out along with CT-attenuation scans on 11 young normal volunteers using a hybrid SPECT/CT scanner. The CT scans were performed at three respiratory phases: end-inspiration (INS), end-expiration (EXP), and the midpoint (MID) between these phases. Using alignment parameters between attenuation maps and SPECT images without attenuation or scatter corrections, quantitative SPECT images were reconstructed, including corrections for attenuation and scatter. Regional radioactivity concentrations normalized by the subjects' weights were compared between CT- and TCT-based attenuation correction techniques.SPECT images with CT attenuation maps at the EXP phase showed significant differences in regional weight-normalized radioactivity concentrations relative to the images using the other attenuation maps (p?0.05), as well as systematic positive bias errors, compared to TCT-based images for all myocardial segments, 5.7%?±?2.7% (1.9% to 10.0%). No significant differences in regional weight-normalized radioactivity concentrations were observed between images with CT attenuation maps at MID and INS phases or between these and the TCT-based images, but regional tendencies were found: for anterior to anterolateral segment, positive bias of 5.0%?±?2.2% (1.3% to 8.1%) and 5.6%?±?1.9% (2.6% to 8.5%) and for inferior to inferoseptal segment, negative bias of -5.3%?±?2.6% (-9.1% to -1.7%) and -4.6%?±?2.5% (-8.8% to -1.5%) for the MID and INS phases, respectively.Use of breath-hold CT attenuation maps at INS and MID phases for attenuation and scatter corrections demonstrated accurate quantitative images that would prove beneficial in cardiac SPECT/CT studies.
Authors: Suri V, Varma S, Joshi K, Malhotra P, Kumari S, Jain S
Abstract: Intravenous immunoglobulin (IVIg) is emerging as the mainstay in the treatment of many autoimmune diseases, including systemic lupus erythematosus. IVIg has been found to be beneficial in myocarditis due to dermatomyositis/polymyositis, Kawasaki disease, and viral myocarditis in children. We report an 18-year-old man of active lupus with worsening cardiac systolic function who did not respond to pulse methylprednisolone and cyclophosphamide, but subsequently showed an improvement in his cardiac function after IVIg administration.
Authors: Aksnes TA, Kjeldsen SE, Rostrup M, Omvik P, Hua TA, Julius S
Abstract: There has been a lot of interest about new-onset diabetes mellitus in recent hypertension trials, but the implications of diabetes development on cardiac outcomes have not been known. In the Valsartan Antihypertensive Long-Term Use Evaluation trial, 15 245 high-risk patients were followed for an average of 4.2 years. At baseline, 5250 patients were diabetic by the 1999 World Health Organization criteria, and among the 9995 nondiabetic patients, 1298 patients developed diabetes during follow-up. We have investigated the influence of diabetes development on outcomes in the Valsartan Antihypertensive Long-Term Use Evaluation trial. The patients with diabetes at baseline and new-onset diabetes were compared with patients who did not develop diabetes by a Cox regression model with adjustment for prespecified covariates (age, diabetes status, left ventricular hypertrophy, baseline coronary heart disease, and randomized study treatment). Patients with diabetes at baseline had the highest cardiac morbidity defined as myocardial infarction and heart failure with a hazard ratio of 2.20 (95% CI: 1.95 to 2.49). The patients with new-onset diabetes had significantly higher cardiac morbidity, especially more congestive heart failure, than those without diabetes, with a hazard ratio of 1.43 (95% CI: 1.16 to 1.77). This indicates that patients who develop diabetes during antihypertensive treatment have cardiac morbidity intermediate between diabetic subjects and those subjects who never had diabetes and that it is of importance to find these patients at risk of diabetes development and optimize lifestyle and medical treatment.
Authors: Klemm HU, Franzen O, Ventura R, Willems S
Abstract: Heart failure as a result of a variety of cardiac diseases is an ever growing, challenging condition that demands profound insight in the electrical and mechanical state of the myocardium. Assessment of cardiac function has largely relied on evaluation of cardiac motion by multiple imaging techniques. In recent years electrical properties have gained attention as heart failure could be improved by biventricular resynchronization therapy. In contrast to early belief, QRS widening as a result of left bundle branch block could not be identified as a surrogate for asynchronous contraction. The combined analysis of electrical and mechanical function is yet a largely experimental approach. Several mapping system are principally capable for this analysis, the most prominent being the NOGA-XP system. Electromechanical maps have concentrated on the local shortening of the reconstructed endocardial surface from end-diastole to end-systole. Temporal analysis of motion propagation, however, is a new aspect. The fundamental principles of percutaneous catheter based activation and motion assessment are reviewed. Related experimental setups are presented and their main findings discussed.
Authors: Liu X, Zhang Q, Yang ZG, Shi K, Xu HY, Xie LJ, Jiang L, Diao KY, Guo YK
Abstract: The aim of this study was to clarify the feasibility of myocardial strain using cardiovascular magnetic resonance (CMR) for the evaluation of left ventricular (LV) deformation in patients with Ebstein's anomaly (EA).We recruited 32 patients with EA and 30 controls for CMR examination and measured LV function, dimension and tissue tracking parameters (the global and regional radial, circumferential and longitudinal peak strain), together with the right ventricle (RV) dimension. LV strain parameters were compared among the controls, patients with preserved LV ejection fraction (LVEF; ?55%), and patients with reduced LVEF (<55%). Pearson's correlation was used to evaluate relationships between tissue tracking parameters with the RVEDD/LVEDD index and LVEF. An ROC analysis was also performed to determine whether the cut-off values for PS could be used to differentiate LV dysfunction between patients with EA and controls. The intraclass correlation coefficient (ICC) was used to assess the inter- and intra-observer variability.The global strain parameters all decreased significantly in the EA group compared with the control group (all P<0.05). Furthermore, the global radial and circumferential peak strain (PS) were obviously even lower in the reduced LVEF group than the strain measured in preserved LVEF groups (28.64% vs. 37.39%, p<0.05; and -8.20% vs. -17.89%; p<0.05; respectively). The regional strain abnormalities in EA patients were mainly involved in basal and middle segments. The results also demonstrated a significant correlation between the ratio of the RV end-diastolic dimension to the LV end-diastolic dimension (RVEDD/LVEDD index) with the global circumferential PS (r=0.508) and the longitudinal PS (r=0.474), as well as a good correlation between radial PS and LVEF (r=0.465). The ICCs for intra- and inter-observer variability were 0.797-0.904 and 0.701-0.896.LV strain serves an earlier and more comprehensive measurement of LV dysfunction than LVEF in EA, which could potentially be included as a supplementary diagnostic procedure in the evaluation of EA.
Authors: Nosek TM, Brotto MA, Jin JP
Abstract: Troponin T (TnT) is an essential protein in the Ca2+ regulatory system of striated of muscle. Three fiber type-specific TnT genes have evolved in higher vertebrates to encode cardiac, slow and fast skeletal muscle TnT isoforms. To understand the functional significance of TnT isoforms, we studied the effects of acidosis on the contractility of transgenic mouse cardiac muscle that expresses fast skeletal muscle TnT. Contractility analysis of intact cardiac muscle strips showed that while no differences were detected at physiological pH, the transgenic cardiac muscle had significantly greater decreases in +dF/dtmax at acidic pH than that of the wild-type control. Contractility of skinned cardiac muscles demonstrated that the presence of fast TnT resulted in significantly larger decreases in force and Ca2+ sensitivity at acidic pH than that of the wild-type control. The effect of TnT isoforms on the tolerance of muscle to acidosis may explain the higher tolerance of embryonic versus adult cardiac muscles. The results are consistent with the hypothesis that charge differences in TnT isoforms contribute to the contractility of muscle. The data further support a hypothesis that slow TnT is similar to the cardiac, but not fast, and TnT may contribute to the higher tolerance of slow muscles to stress conditions. Therefore, TnT isoform diversity may contribute to the compatibility of muscle thin filaments to cellular environments in different fiber types, during development and functional adaptation.
Authors: Brouillette J, Grandy SA, Jolicoeur P, Fiset C
Abstract: Pharmacological agents used to treat patients with AIDS have been associated with QT prolongation and result in delayed repolarization. New evidence suggests that delayed repolarization can occur independently of pharmacological therapy. However, the effect of HIV on ventricular repolarization has not been investigated. Therefore, the objective of this study was to characterize cardiac repolarization in a mouse model of human HIV disease. All experiments were conducted on HIV transgenic mice (CD4C/HIV). These mice express the human HIV gene nef in cells of immune system and develop a severe AIDS-like disease that is similar to that observed in humans. ECG was recorded in conscious free moving mice and patch-clamp techniques were used to record action potentials and K+ current densities in single ventricular myocytes. Results showed that the QT interval and action potential duration were significantly prolonged in CD4C/HIV mice compared to wild-type littermates. This delay in repolarization was associated with a significant reduction in outward K+ currents. Echocardiography showed that cardiac structure and function were similar in CD4C/HIV and littermate control mice. This suggests that the changes in ventricular repolarization were not the result of heart failure or cardiac hypertrophy. Overall, this study shows that repolarization was delayed in CD4C/HIV mice and that this phenotype occurred in the absence of any pharmacological intervention. Thus, it appears that HIV may be responsible for the delayed ventricular repolarization phenotype observed in CD4C/HIV mice.