Flow Mapping Research Articles

EXPRESS: Right Heart in Pulmonary Hypertension: From Adaptation to Failure.

Right ventricular (RV) failure (RVF) has garnered significant attention in recent years because of its negative impact on clinical outcomes in patients with pulmonary hypertension (PH). PH triggers a series of events, including activation of several signaling pathways that regulate cell growth, metabolism, extracellular matrix remodeling, and energy production. These processes render the RV adaptive to PH. However, RVF develops when PH persists, accompanied by RV ischemia, alterations in substrate and mitochondrial energy metabolism, increased free oxygen radicals, increased cell loss, downregulation of adrenergic receptors, increased inflammation and fibrosis, and pathologic microRNAs. Diastolic dysfunction is also an integral part of RVF. Emerging non-invasive technologies such as molecular or metallic imaging, cardiac MRI, and ultrafast Doppler coronary flow mapping will be valuable tools to monitor RVF, especially the transition to RVF. Most PH therapies cannot treat RVF once it has occurred. A variety of therapies are available to treat acute and chronic RVF, but they are mainly supportive, and no effective therapy directly targets the failing RV. Therapies that target cell growth, cellular metabolism, oxidative stress, and myocyte regeneration are being tested preclinically. Future research should include establishing novel RVF models based on existing models, increasing use of human samples, creating human stem cell-based in vitro models, and characterizing alterations in cardiac excitation–contraction coupling during transition from adaptive RV to RVF. More successful strategies to manage RVF will likely be developed as we learn more about the transition from adaptive remodeling to maladaptive RVF in the future.

MANAGEMENT ACCOUNTING TOOLS FOR IMPROVEMENT OF PRODUCTION PROCESS - LEAN PRODUCTION SYSTEM

Business in modern business conditions requires a continuous process of improvement and investment in all activities in the company. In order to survive on the market, resist the challenges of competition, but also the demands of customers, companies are constantly innovating the production process in an effort to improve all the company's activities. One of the production systems that proved to be suitable for continuous improvement and improvement of the production process is Lean production system. It represents the way companies react to the challenges of the present and the future. The Lean production system offers a variety of instruments, and for their implementation and application, managers are at all levels of responsibility and responsibility. Bearing this in mind, it can be said that the Lean production system is part of the management accounting. In addition, it represents a complete philosophy of thinking and action, which results in significant results by adequate application. The condition and the assumption that this management philosophy will lead to proper effectiveness and efficiency and enable them to continually improve in the function of maximizing profits is the authorization of employees to engage in the process of continuous improvement and decision-making. Lean is based on certain principles and philosophies, including customer value, value flow mapping, continuous flow, system requirements, and continuous improvements. Lean focuses on the added value. Lean's principle is a continuous search for perfection, perfection in production and business cooperation, with complete elimination of losses. Companies that implement the Lean Concept are constantly looking for ways to continually improve their efficiency, reduce costs and improve the quality of their products.

The Analysis of a Production Flow with the Help of Value Stream Mapping

The main aim of Lean Manufacturing concept is to produce more with less: space, stock, workforce and time. The companies that along the years implemented Lean Manufacturing, reached a spectacular development, mainly because with the same workforce and financial resources, succeeded to increase significantly their profit (some reached up to 300-400% increase). The strength of Lean concept is the calculation of value of product for the final client, considering each stage of manufacturing. Therefore, the main aim of this paper is to analyze and improve the manufacturing flow of a component, from the system entry point to its exit using Flow Mapping and Value Stream Mapping. After all the actions on improving the flow, the activities without added value decreased with 15.92% and the lead time with 15.61%

P1094D CMR flow mapping and strain analysis of a muscular left ventricular diverticulum

P1094D CMR flow mapping and strain analysis of a muscular left ventricular diverticulum

IFPNA: A Flexible and Efficient Deep Learning Processor in 28-nm CMOS Using a Domain-Specific Instruction Set and Reconfigurable Fabric

This paper presents iFPNA, instruction-and-fabric programmable neuron array: a deep learning processor using a neural network specific instruction set architecture and reconfigurable fabric. The design is motivated by the trade-off between the efficiency and flexibility of deep learning processor designs. The proposed architecture contains a controller for programming, a global feature buffer for data arrangement, and 16 reconfigurable neuron slices for computing. The controller uses dedicated instructions to control the feature buffer and neuron slices. The neuron slices support multiplication-and-accumulation, non-linear activation, element-wise operation, and the pooling of different bit-width and kernel size. Different deep neural networks are mapped to iFPNA such as conventional CNNs, depthwise/pointwise CNNs, LSTMs, and GRUs. The paper also discusses various data flow mapping schemes. An iFPNA prototype is designed and fabricated on 28-nm HPC CMOS technology. Measurement results show that the iFPNA achieves a peak energy efficiency of 1.72 TOPS/W running at 30-MHz clock rate with 0.63 V voltage supply. The measured latency on AlexNet is 57.2 ms and on LSTM-512 is 40 ms at 125 MHz clock rate.

Measurement of the zeta-potential of solid surfaces through Laser Doppler Electrophoresis of colloid tracer in a dip-cell: Survey of the effect of ionic strength, pH, tracer chemical nature and size

Measurement techniques for detecting surface charge have gained attention in the last few decades due to the importance of this parameter in many scientific and industrial applications. The estimation of macroscopic surface zeta-potential (ζ) is customarily performed via streaming potential measurements. Recently, a simple and cost-effective Malvern Zetasizer accessory has been introduced which makes use of electroosmotic flow mapping (EOFM) to determine surface charge of hard surfaces. In this work we propose a measurement strategy that considers the key parameters influencing the reliability of surface ζ values. With this purpose, the role of the ionic strength, sample cleaning, tracer particle size and chemical nature on the determination of ζ for borosilicate glass coverslips have been investigated. ζ values obtained in presence of adjusted parameters was finally compared to the equivalent results of streaming potential technique, validating the proposed measurement strategy.

Intraventricular vector flow mapping by 3-D doppler echo

Heart failure is the cardiomyopathy that will have the greatest impact on the lives of French in the coming decades. It is a cardiac disease that affects the ability of the heart to meet the oxygen...

Evaluation of hemodynamics in patients with hypertrophic cardiomyopathy by vector flow mapping: Comparison with healthy subjects.

The present study investigated the role of energy loss assessed by vector flow mapping (VFM) in patients with hypertrophic cardiomyopathy (HCM). VFM analysis was performed in 42 patients with HCM and in 40 control subjects, which were matched for age, sex and left ventricular (LV) ejection fraction. The intra-LV and left atrial blood flow were obtained from the apical 3-chamber view, and the energy loss (EL) during the systolic and diastolic phases was calculated. The measurements were averaged over three cardiac cycles and indexed to body surface area. Compared with the controls, the left ventricular energy loss (LVEL)-total value was significantly decreased in patients with HCM during the diastolic phase (P1, P2 and P3; all P<0.05). A tendency for increased systolic LVEL-total values was observed in the patients with HCM compared with the controls (P>0.05). LVEL-base values were decreased in the patients with HCM during P1 and P2 (slow filling time). Compared with the controls, patients with HCM had lower LVEL-mid values during the diastolic phases (P0, P1, P2 and P3; all P<0.05). However, the LVEL-mid value of patients with HCM was higher compared with that of the controls during systolic P5 (P<0.05). LVEL-apex was decreased in patients with HCM during P0, P2 and P3. Compared with the controls, the left atrial energy loss (LAEL) of all three phases in patients with HCM were lower (each P<0.01). The diastolic LVEL values were significantly lower in patients with HCM compared with the controls; however, the systolic LVEL levels tended to be higher in HCM. The LAEL of the reservoir phase, conduit phase and atrial systolic phase were decreased in HCM compared with controls. The present study demonstrated that measurement of EL by VFM is a sensitive method of determining subclinical LV dysfunction in patients with HCM. The value of EL has been considered to be a quantitative parameter for the estimation of the efficiency of intraventricular blood flow.

Ultrasonic Vascular Vector Flow Mapping for 2-D Flow Estimation

A vascular vector flow mapping (VFM) method visualizes 2-D cardiac flow dynamics by estimating the radial component of flow from the Doppler velocities and wall motion velocities using the mass conservation equation. Although VFM provides 2-D flow, the algorithm is applicable only to bounded regions. Here, a modified VFM algorithm, vascular VFM, is proposed so that the velocities are estimated regardless of the flow geometry. To validate the algorithm, a phantom mimicking a carotid artery was fabricated and VFM velocities were compared with optical particle image velocimetry (PIV) data acquired in the same imaged plane. The validation results indicate that given optimal beam angle condition, VFM velocitiy is fairly accurate, where the correlation coefficient R between VFM and PIV velocities is 0.95. The standard deviation of the total VFM error, normalized by the maximum velocity, ranged from 8.1% to 16.3%, whereas the standard deviation of the measured input errors ranged from 8.9% to 12.7% for color flow mapping and from 4.5% to 5.9% for subbeam calculation. These results indicate that vascular VFM is reliable as its accuracy is comparable to that of conventional Doppler-flow images.

Comparison of Four Environmental Assessment Tools in Swedish Manufacturing: A Case Study

To achieve sustainable development goals, it is essential to include the industrial system. There are sufficient numbers of tools and methods for measuring, assessing and improving the quality, productivity and efficiency of production, but the number of tools and methods for environmental initiatives on the shop floor is rather low. Incorporating environmental considerations into production and performance management systems still generally involves a top-down approach aggregated for an entire manufacturing plant. Green lean studies have been attempting to fill this gap to some extent, but the lack of detailed methodologies and practical tools for environmental manufacturing improvement on the shop floor is still evident. This paper reports on the application of four environmental assessment tools commonly used among Swedish manufacturing companies—Green Performance Map (GPM), Environmental Value Stream Mapping (EVSM), Waste Flow Mapping (WFM), and Life Cycle Assessment (LCA)—to help practitioners and scholars to understand the different features of each tool, so in turn the right tool(s) can be selected according to particular questions and the industrial settings. Because there are some overlap and differences between the tools and a given tool may be more appropriate to a situation depending on the question posed, a combination of tools is suggested to embrace different types of data collection and analysis to include different environmental impacts for better prioritization and decision-making.

Sex differences in insular functional connectivity in response to noxious visceral stimulation in rats

Insular cortex (INS) plays a critical role in pain processing and shows sex differences in functional activation during noxious visceral stimulation. Less is known regarding functional interactions within the INS and between this structure and other parts of the brain. Cerebral blood flow mapping was performed using [14C]-iodoantipyrine perfusion autoradiography in male and female rats during colorectal distension (CRD) or no distension (controls). Forty regions of interest (ROIs) were defined anatomically to represent the granular, dysgranular, and agranular INS along the anterior-posterior (A-P) axis. Inter-ROI correlation matrices were calculated for each group to characterize intra-insular functional connectivity (FC). Results showed a clear FC segregation within the INS into an anterior (rostral to bregma +2.4 mm), a posterior (caudal to bregma −1.2 mm), and a mid INS subregion in between. Female controls showed higher FC density compared to males. During CRD, intra-insular FC density decreased greatly in females, but only modestly in males, with a loss of long-range connections between the anterior and mid INS noted in both sexes. New functional organization was characterized in both sexes by a cluster in the mid INS and primarily short-range FC along the A-P axis. Seed correlation analysis during CRD showed sex differences in FC of the anterior and mid agranular INS with the medial prefrontal cortex, thalamus, and brainstem areas (periaqueductal gray, parabrachial nucleus), suggesting sex differences in the modulatory aspect of visceral pain processing. Our findings suggest presence of substantial sex differences in visceral pain processing at the level of the insula.

Assessment of Wall Shear Stress on the Aortic Valve in Patients with Left Ventricular Assist Device Using Vector Flow Mapping

Purpose De novo aortic insufficiency is one of unresolved complications after left ventricular assist device (LVAD) implant. It has been hypothesized that decreased and oscillatory wall shear stress (WSS) on the aortic valve following LVAD implantation cause leaflet degeneration resulting in AI. We developed novel approach to measure WSS on the aortic valve using vector flow mapping (VFM) images. Methods Aortic root color Doppler image was obtained using intraoperative epiaortic echocardiogram in 6 patients who received LVAD implant and 8 patients undergoing LVAD explant and heart transplant. As a control group, we enrolled 5 patients undergoing CABG surgery. Using obtained images, WSS and oscillatory shear index (OSI) on the right coronary cusp (RCC) was calculated with off-line software, Echo VFM® (Cardio Flow Design, Tokyo, Japan) (Figure). Results Image analysis was successful in all patients. The WSS on the ventricularis of the RCC was significantly lower in the LVAD group compared to control (0.09±0.06 vs. 0.35±0.27 Pa, p Conclusion Significantly lower WSS on the ventricularis may be accountable for AV degeneration and subsequent De Novo AI in patients with LVAD.

Blood Flow Kinetic Energy of Right Ventricular Outflow Tract: A Marker for Right Ventricular Global Systolic Function

Purpose Right ventricular (RV) failure remains a major concern in heart failure (HF) patients undergoing LVAD surgery. We aimed to measure flow kinetic energy (KE) of the RV outflow tract (OT) - a new marker of RV global systolic function - and assess its relationship to well-established echocardiographic and hemodynamic parameters of RV performance in heart failure (HF) and LVAD pts. Methods Twenty-one subjects were prospectively enrolled: 12 HF pts (2 NYHA Class II and 10 Class IV), 3 HeartMate II (HMII) and 6 healthy controls (C). Echocardiographic parameters of RV function (TAPSE, St’, Et’, IVA, MPI) and RV inflow-outflow color Doppler images were recorded on all pts. Invasive hemodynamic parameters of RV function and RV failure risk score (RVFRS) were collected in all Class IV pts. KE-RVOT was derived from color Doppler images using a vector flow mapping proprietary software, Echo VFM® (Cardio Flow Design, Tokyo, Japan) (Figure). Kruskal-Wallis test was performed for comparison of each group. Correlation between KE-RVOT and echocardiographic/hemodynamic parameters as well as RVFRS was assessed by linear regression analysis. Results KERVOT (Median ± IQR) was higher in C (56.98 [37.63 to 97.21] mW/m) than in Class II HF (26.60 [26.14 to 27.05] mW/m, p<0.05) and further declined in Class IV HF (7.45 [4.87 to 10.46] mW/m, p<0.05)). LVAD therapy partially restored KE-RVOT (23.17 [9.77 to 25.03] mW/m, p<0.05)) to levels similar to Class II HF (Figure). KE-RVOT was significantly related to TAPSE, St’, CVP/PCWP, and PAPi (r = 0.5887, 0.6671, -0.6942, and 0.7899, respectively, all p<0.05) but not to RVFRS. Conclusion KE-RVOT, a novel noninvasive measure of RV function, strongly correlates with well-established markers of RV performance. The utility of KE-RVOT in prediction of RV failure post LVAD requires further study. Right ventricular (RV) failure remains a major concern in heart failure (HF) patients undergoing LVAD surgery. We aimed to measure flow kinetic energy (KE) of the RV outflow tract (OT) - a new marker of RV global systolic function - and assess its relationship to well-established echocardiographic and hemodynamic parameters of RV performance in heart failure (HF) and LVAD pts. Twenty-one subjects were prospectively enrolled: 12 HF pts (2 NYHA Class II and 10 Class IV), 3 HeartMate II (HMII) and 6 healthy controls (C). Echocardiographic parameters of RV function (TAPSE, St’, Et’, IVA, MPI) and RV inflow-outflow color Doppler images were recorded on all pts. Invasive hemodynamic parameters of RV function and RV failure risk score (RVFRS) were collected in all Class IV pts. KE-RVOT was derived from color Doppler images using a vector flow mapping proprietary software, Echo VFM® (Cardio Flow Design, Tokyo, Japan) (Figure). Kruskal-Wallis test was performed for comparison of each group. Correlation between KE-RVOT and echocardiographic/hemodynamic parameters as well as RVFRS was assessed by linear regression analysis. KERVOT (Median ± IQR) was higher in C (56.98 [37.63 to 97.21] mW/m) than in Class II HF (26.60 [26.14 to 27.05] mW/m, p<0.05) and further declined in Class IV HF (7.45 [4.87 to 10.46] mW/m, p<0.05)). LVAD therapy partially restored KE-RVOT (23.17 [9.77 to 25.03] mW/m, p<0.05)) to levels similar to Class II HF (Figure). KE-RVOT was significantly related to TAPSE, St’, CVP/PCWP, and PAPi (r = 0.5887, 0.6671, -0.6942, and 0.7899, respectively, all p<0.05) but not to RVFRS. KE-RVOT, a novel noninvasive measure of RV function, strongly correlates with well-established markers of RV performance. The utility of KE-RVOT in prediction of RV failure post LVAD requires further study.

Wall Shear Stress in the Middle Cerebral Artery of HM II Patients - A Prospective, Mechanistic Study Using Vector Flow Mapping

Purpose It has been proposed that the high prevalence of bleeding events in continuous-flow left ventricular assist device (CF-LVAD) patients may be lowered by increasing von Willebrand factor-release via augmented peripheral pulsatility (PI). However, the hemostatic effects of increased PI may be offset by concomitant increases in local wall shear stress (WSS) - which is known to stimulate the endothelial release of anti-thrombotic factors (NO, prostacyclin, thrombomodulin). Hypothesis Higher pulsatility in the middle cerebral artery of CF-LVAD patients will be significantly associated with increased local WSS. Methods Video loops of color Doppler recordings from the middle cerebral artery were obtained in 8 HeartMate II (HM II) patients and 8 healthy controls. Data were analyzed offline with validated vector flow mapping software. WSS was calculated as: viscosity*(du/dy), according to Newton's law. Viscosity was corrected by using individuals’ hematocrit. Importantly, we determined not only peak WSS but also WSS per beat (area under the curve) and WSS/min (WSS/beat * heart rate). PI was measured from angle-corrected pulsed-wave Doppler velocities. Results Peak WSS and WSS/beat were lower in HM II (P = 0.05) but WSS/min was not different (P > 0.05). Supporting our hypothesis, WSS and pulsatility index (PI) were strongly correlated non-linearly in HM II patients (r2 = 0.94) and shared a common linear slope with healthy controls between a PI of ∼0.45 and ∼0.90 (Fig. 1). Conclusion In CF-LVAD patients, a strong curvilinear relationship was noted between cerebral PI and WSS, with linear increases in WSS shown above a PI of ∼0.45. These data suggest a threshold for PI and its interaction with endothelium-dependent hemostatic and anti-thrombotic activity. Future work is warranted to investigate whether alteration of the PI-WSS relationship will influence the release of hemostatic or anti-thrombotic factors and reduce cerebral bleeding in CF-LVAD patients.

Successful catheter ablation of atrial fibrillation improves but not reverses the abnormalities of left atrial mechanics and energy loss.

Dissipative energy loss (EL), a new index to quantify the inefficient blood flow, has not been explored within left atrium (LA) in patients with atrial fibrillation (AF). We aimed to study the intra-atrial flow and mechanics in patients with AF before and after successful catheter ablation by evaluating EL and LA global longitudinal strain (LAS). In our study, there were 53 patients undergoing catheter ablation for AF at baseline (AF group) and 33 age- and sex-matched controls. They were both assessed of LA EL using vector flow mapping (VFM) and of LAS using two-dimensional tracking (2DTT) during systole (sys), early diastole (ed), and atrial contraction phase (ac). Out of 53 patients, 37 patients who sustained sinus rhythm and carried out the echocardiographic examination at 3 and 6months follow-up were evaluated of change in EL and LAS. The independent predictors of EL during three phases in AF group were performed using stepwise multivariate linear regression analyses. Left atrium EL and LAS among all phases in AF group were significantly lower than controls (all P<0.01). During follow-up, LASsys and LASac both significantly improved at 3 and 6months (both P<0.01), and ELac significantly increased after 6months (P<0.05); ELsys, ELed and LASed were no significant change; EL and LAS among all phases were no normalized during follow-up. The independent predictors of EL were: for ELsys, BSA (P=0.004) and LASac (P=0.025); for ELed, E (P=0.001) and A (P=0.014); for ELac, E/A (P<0.001). Vector flow mapping and 2DTT revealed impaired intra-atrial flow and mechanics. Successful catheter ablation for AF slightly improves but not reverses the aforementioned impairment, indicating the continuous LA dysfunction.

DIASTOLIC ENERGY LOSS BY VECTOR FLOW MAPPING AS A NEW MEASURE OF DIASTOLIC DYSFUNCTION IN HEART FAILURE PATIENTS WITH REDUCED EJECTION FRACTION

Vector Flow mapping (VFM) enables noninvasive quantification of cardiac flow dynamics. The impact of diastolic dysfunction on energy loss by VFM in heart failure (HF) patients is unclear. Our aim was to assess the association of VFM diastolic energy loss with conventional measures of diastolic

ENERGY LOSS BY VECTOR FLOW MAPPING IS ASSOCIATED WITH SYMPTOM SEVERITY AND SERUM BIOMARKERS IN HEART FAILURE PATIENTS WITH REDUCED EJECTION FRACTION

Vector flow mapping (VFM) can quantify left ventricular (LV) flow mechanics noninvasively. VFM can measure LV energy loss and pump efficiency. However, the association of LV energy loss to symptom severity and serum biomarkers in heart failure patients with reduced ejection fraction (HFrEF) is

SPLENIC SIZE RELATION TO THE PORTAL VEIN DOPPLER ANALYSIS IN SUDANESE LIVER TRANSPLANTS

The purpose of this study was to identify the specific Doppler criteria for the portal vein as well as the spleen length or volume in liver transplants. A relative study was done after performing venous Doppler sonographic studies in 45 liver transplant cases (4 whole liver, 41 lobar) with no known vascular complications. The ultrasonic Doppler study were targeted to the portal vein flow direction, flow velocity in Doppler level and the caliber in gray scale level. Average gray scale and color flow mapping appearances as well as normal monophasic wave character was found. The following Doppler parameters were evaluated: for the portal veins, venous pulsatility index. There were no cases of portal vein obstruction found in our sample (neither stenosis, nor occlusion). Mean portal vein velocity was (less than 55 cm /s), the splenic length was (13.7±1.5). The relation between the portal venous index, and the splenic length was built. Both are useful parameters for diagnosing liver transplants complications.

Assessment of left ventricular diastolic function by vector flow mapping in patients with mitral valve plasty

Objective To assess left ventricular diastolic function by vector flow mapping (VFM) in patients with mitral valve plasty. Methods A total of 30 patients undergoing mitral valve plasty were enrolled. The dissipative energy loss (EL) of basal, middle, apical and global left ventricular segments in rapid filing phase, slow filling phase, and atria contract period were measured by VFM, and the EL above were compared in 1 week preoperatively, 1 week and 1 month postoperatively. Results Compared with 1 week preoperatively, EL in all diastole in basal and middle left ventricular segments were significantly increased at 1 week after operation (all P<0.05), EL in some diastole in apical and global left ventricular segments were significantly increased at 1 week after operation (all P<0.05), and EL in all diastole in all left ventricular segments were significantly increased at 1 month after operation (all P<0.05). Compared with 1 week postoperatively, EL in all diastole in all left ventricular segments were significantly increased at 1 month after operation (all P<0.05). Conclusions VFM can quantitatively evaluate left ventricular diastolic function, and helps to evaluate treatment response at preoperative and postoperative. Key words: Vector flow mapping; Mitral valve annuloplasty; Ventricular function, left; Energy loss

Velocity characteristics of atrial fibrillation sources determined by electrographic flow mapping before and after catheter ablation

BackgroundElectrographic-Flow-(EGF)-Mapping is a novel method to identify Atrial Fibrillation (AF) drivers. Sources of excitation during AF can be characterized and monitored. ObjectiveThe aim of this study was to evaluate the correlation between velocity of EGF around a respective AF source and its spatial variability (SV) and stability (SST). Methods25 patients with AF were included in this study (persistent: n = 24, long-standing persistent: n = 1; mean age 70 ± 8.3 years, male: n = 17). Focal impulse and Rotor-Mapping (FIRM) was performed in addition to pulmonary vein isolation. One-minute epochs of unipolar electrograms recorded via a 64-pole basket catheter in both atria were re-analyzed with EGF-Mapping. SST was calculated as the percentage of time in which a source was detected. ResultsAF sources identified with EGF-Mapping show a wide range of SV during 1 min covering between 0.12% and 38% of the recorded basket-catheter surface. The 12 atria where the sources showed highest temporal stability (TS; between 34% and 97% of 1 min recorded) and those 12 with the lowest TS (between 11 and 20%) differed significantly in their velocities (17.8 el/s vs 12.2 el/s; p < 0.01). In 11 atria ablation caused an average decrease of TS by 47% and of velocity by 27% while SV more than doubled. ConclusionLess stable AF-sources with high spatial variability showed reduced excitation propagation velocity while stable AF sources displayed a high average velocity in their vicinity. Importantly, catheter ablation reduced stability of sources and velocity suggesting a role of these parameters in guidance of ablation. Condensed abstractElectrographic Flow (EGF)-Mapping is a novel method to identify Atrial Fibrillation (AF) drivers based on modeling of an electrical potential surface and subsequent flow analysis. Sources of excitation during AF can be characterized and monitored. The aim of this study was to evaluate the correlation between velocity of EGF around a respective AF source and its spatial variability and stability. Less stable AF sources with high spatial variability showed reduced excitation propagation velocity while very stable AF sources displayed a high average velocity in their vicinity. Catheter ablation reduced stability of sources and velocity.