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Background: Two opposite views of cardiac growth are currently held; one views the heart as a static organ characterized by a large number of cardiomyocytes that are present at birth and live as long as the organism, and the other views the heart a highly plastic organ in which the myocyte compartment is restored several times during the course of life., Methods and Results: The average age of cardiomyocytes, vascular endothelial cells (ECs), and fibroblasts and their turnover rates were measured by retrospective (14)C birth dating of cells in 19 normal hearts 2 to 78 years of age and in 17 explanted failing hearts 22 to 70 years of age. We report that the human heart is characterized by a significant turnover of ventricular myocytes, ECs, and fibroblasts, physiologically and pathologically. Myocyte, EC, and fibroblast renewal is very high shortly after birth, decreases during postnatal maturation, remains relatively constant in the adult organ, and increases dramatically with age. From 20 to 78 years of age, the adult human heart entirely replaces its myocyte, EC, and fibroblast compartment ≈8, ≈6, and ≈8 times, respectively. Myocyte, EC, and fibroblast regeneration is further enhanced with chronic heart failure., Conclusions: The human heart is a highly dynamic organ that retains a remarkable degree of plasticity throughout life and in the presence of chronic heart failure. However, the ability to regenerate cardiomyocytes, vascular ECs, and fibroblasts cannot prevent the manifestations of myocardial aging or oppose the negative effects of ischemic and idiopathic dilated cardiomyopathy.

Background: Ischemic mitral regurgitation, a complication of myocardial infarction and coronary artery disease more generally, is associated with a high mortality rate and is estimated to affect 2.8 million Americans. With 1-year mortality rates as high as 40%, recent practice guidelines of professional societies recommend repair or replacement, but there remains a lack of conclusive evidence supporting either intervention. The choice between therapeutic options is characterized by the trade-off between reduced operative morbidity and mortality with repair versus a better long-term correction of mitral insufficiency with replacement. The long-term benefits of repair versus replacement remain unknown, which has led to significant variation in surgical practice., Methods and Results: This article describes the design of a prospective randomized clinical trial to evaluate the safety and effectiveness of mitral valve repair and replacement in patients with severe ischemic mitral regurgitation. This trial is being conducted as part of the Cardiothoracic Surgical Trials Network. This article addresses challenges in selecting a feasible primary end point, characterizing the target population (including the degree of mitral regurgitation) and analytical challenges in this high mortality disease., Conclusions: The article concludes by discussing the importance of information on functional status, survival, neurocognition, quality of life, and cardiac physiology in therapeutic decision making., (Copyright © 2012. Published by Mosby, Inc.)

Purpose: The purpose of this study was to evaluate the histological features of the pulp tissue in primary pig teeth submitted to pulpotomy and capped with calcium hydroxide-based and standardized propolis extract-based pastes, and the combination of these pastes., Methods: Nine 4-month-old male pigs were used in this study, which were distributed into 4 groups, according to the studied pastes: Group 1-calcium hydroxide; Group2-standardized propolis extract; Group 3-combination of pastes 1 and 2 in the proportion 1:1; and Group 4-control. The teeth used for the pulpotomy were the 4 mandibular primary incisors., Results: After 7, 21, and 42 days, the animals were killed and the teeth were re-moved for histological analysis. At 42 days, all teeth in Groups 1 to 3 presented a complete hardtissue barrier and the pulp tissue beneath was without inflammation., Conclusion: According to these findings, calcium hydroxide and standardized propolis extract favored the formation of a hard tissue barrier in primary pig teeth submitted to pulpotomy.

Rationale: Age and coronary artery disease may negatively affect the function of human cardiac stem cells (hCSCs) and their potential therapeutic efficacy for autologous cell transplantation in the failing heart., Objective: Insulin-like growth factor (IGF)-1, IGF-2, and angiotensin II (Ang II), as well as their receptors, IGF-1R, IGF-2R, and AT1R, were characterized in c-kit(+) hCSCs to establish whether these systems would allow us to separate hCSC classes with different growth reserve in the aging and diseased myocardium., Methods and Results: C-kit(+) hCSCs were collected from myocardial samples obtained from 24 patients, 48 to 86 years of age, undergoing elective cardiac surgery for coronary artery disease. The expression of IGF-1R in hCSCs recognized a young cell phenotype defined by long telomeres, high telomerase activity, enhanced cell proliferation, and attenuated apoptosis. In addition to IGF-1, IGF-1R(+) hCSCs secreted IGF-2 that promoted myocyte differentiation. Conversely, the presence of IGF-2R and AT1R, in the absence of IGF-1R, identified senescent hCSCs with impaired growth reserve and increased susceptibility to apoptosis. The ability of IGF-1R(+) hCSCs to regenerate infarcted myocardium was then compared with that of unselected c-kit(+) hCSCs. IGF-1R(+) hCSCs improved cardiomyogenesis and vasculogenesis. Pretreatment of IGF-1R(+) hCSCs with IGF-2 resulted in the formation of more mature myocytes and superior recovery of ventricular structure., Conclusions: hCSCs expressing only IGF-1R synthesize both IGF-1 and IGF-2, which are potent modulators of stem cell replication, commitment to the myocyte lineage, and myocyte differentiation, which points to this hCSC subset as the ideal candidate cell for the management of human heart failure.

Rationale: Understanding the mechanisms that regulate trafficking of human cardiac stem cells (hCSCs) may lead to development of new therapeutic approaches for the failing heart., Objective: We tested whether the motility of hCSCs in immunosuppressed infarcted animals is controlled by the guidance system that involves the interaction of Eph receptors with ephrin ligands., Methods and Results: Within the cardiac niches, cardiomyocytes expressed preferentially the ephrin A1 ligand, whereas hCSCs possessed the EphA2 receptor. Treatment of hCSCs with ephrin A1 resulted in the rapid internalization of the ephrin A1-EphA2 complex, posttranslational modifications of Src kinases, and morphological changes consistent with the acquisition of a motile cell phenotype. Ephrin A1 enhanced the motility of hCSCs in vitro, and their migration in vivo following acute myocardial infarction. At 2 weeks after infarction, the volume of the regenerated myocardium was 2-fold larger in animals injected with ephrin A1-activated hCSCs than in animals receiving control hCSCs; this difference was dictated by a greater number of newly formed cardiomyocytes and coronary vessels. The increased recovery in myocardial mass with ephrin A1-treated hCSCs was characterized by further restoration of cardiac function and by a reduction in arrhythmic events., Conclusions: Ephrin A1 promotes the motility of EphA2-positive hCSCs, facilitates their migration to the area of damage, and enhances cardiac repair. Thus, in situ stimulation of resident hCSCs with ephrin A1 or their ex vivo activation before myocardial delivery improves cell targeting to sites of injury, possibly providing a novel strategy for the management of the diseased heart.

Background: Cardiac stem cells (CSCs) delivered to the infarcted heart generate a large number of small fetal-neonatal cardiomyocytes that fail to acquire the differentiated phenotype. However, the interaction of CSCs with postmitotic myocytes results in the formation of cells with adult characteristics., Methods and Results: On the basis of results of in vitro and in vivo assays, we report that the commitment of human CSCs (hCSCs) to the myocyte lineage and the generation of mature working cardiomyocytes are influenced by microRNA-499 (miR-499), which is barely detectable in hCSCs but is highly expressed in postmitotic human cardiomyocytes. miR-499 traverses gap junction channels and translocates to structurally coupled hCSCs favoring their differentiation into functionally competent cells. Expression of miR-499 in hCSCs represses the miR-499 target genes Sox6 and Rod1, enhancing cardiomyogenesis in vitro and after infarction in vivo. Although cardiac repair was detected in all cell-treated infarcted hearts, the aggregate volume of the regenerated myocyte mass and myocyte cell volume were greater in animals injected with hCSCs overexpressing miR-499. Treatment with hCSCs resulted in an improvement in ventricular function, consisting of a better preservation of developed pressure and positive and negative dP/dt after infarction. An additional positive effect on cardiac performance occurred with miR-499, pointing to enhanced myocyte differentiation/hypertrophy as the mechanism by which miR-499 potentiated the restoration of myocardial mass and function in the infarcted heart., Conclusions: The recognition that miR-499 promotes the differentiation of hCSCs into mechanically integrated cardiomyocytes has important clinical implications for the treatment of human heart failure.

This paper deals with contact currents that may occur when the human body is in contact with two electrodes at different electrical potentials, e.g., an electrical/electronic device and the floor. Actually, any device must comply not only with electromagnetic compatibility and safety requirements, but also with specific electromagnetic field exposure recommendations in order to prevent health hazards for the occupational and general public population. Since the contact currents depend on the applied voltage and on the human body impedance, this last parameter has been measured for several configurations in a broadband frequency range, from 40 Hz to 110 MHz. From the measurement results, a new equivalent circuit of the human body impedance is derived by using a vector-fitting procedure. This equivalent circuit is very easy and can be adopted for compliance tests against contact currents.

Opinion Statement: As heart transplantation and mechanical assist technology are inadequate solutions for the growing clinical epidemic of heart failure, myocardial regeneration has moved to the forefront. Multiple laboratories using a variety of cell types have demonstrated myocardial repair in different animal models. Translating these results into clinical practice through clinical trial research has thus far proved challenging. Amassing clinical evidence suggests that cell therapy is safe and offers a modest clinical benefit, but the long-term effect of such therapy as well as the overall impact on the natural progression of heart failure and, ultimately, survival are unknown. Furthermore, cost-benefit analysis of such therapy, which will likely become increasingly important as health care reform takes shape, has not been examined to any degree. Although scientific competition has driven this field with remarkable speed, it is also responsible for its fragmentation, with multiple avenues of pursuit happening in parallel. Consensus opinion is absent with respect to mechanism of action, effectiveness of cell type or delivery method, timing and dosing of cell therapy, adjunctive medication or therapies, and optimum cell type or combination of cell types. Nevertheless, in the arena of clinical medicine, ease of cell availability and cell delivery has proved paramount to cell type selection. The flourish of clinical trials investigating bone marrow-derived stem cells (BMSCs) delivered via direct intracoronary injection testifies to this opinion. The modest improvements in cardiac function demonstrated in trials to date will likely not have a significant clinical impact. We expect, however, that scientific competition will make continued contributions over the next decade that will propel the field forward, resulting in more pronounced clinical benefits in future trials. The authors further believe that the realization of true cardiac regeneration will require the use of autologous cells more capable of retention and differentiation to cardiac cell lineages. We believe that endogenous cardiac progenitor cells have superior regenerative potential to current cell types in this regard. The difficulty in accessing, isolating, and expanding these cells has resulted in less preclinical and clinical interest. Ongoing investigation will better define the capabilities of these cardiac progenitor cells.

Congenitally corrected transposition of the great arteries (ccTGA) accounts for less that 1% of cardiac anomalies, and is defined as ventriculoarterial and atrioventricular (AV) discordance. The double discordant connection allows for survival with the right ventricle performing as the systemic ventricle, and the left ventricle as the pulmonary ventricle. We report a case of ccTGA in a 35-year-old male with situs inversus totalis status post repair of a ventricular septal defect (VSD) with a residual VSD, severe systemic AV valve regurgitation, and coronary artery disease who presented with chest pain. He subsequently underwent tricuspid valve replacement and VSD repair, followed by percutaneous coronary revascularization. This case highlights many important issues of adults with congenital cardiac disease, as well as the specific surgical management of anomalies associated with ccTGA. We review the literature and discuss the management of these complicated patients., (© 2010 Copyright the Authors. Congenital Heart Disease © 2010 Wiley Periodicals, Inc.)

Background: The HeartMate II (HMII) Left Ventricular Assist System (Thoratec Corporation, Pleasanton, CA, USA), an axial continuous-flow left ventricular assist device (LVAD), has been approved for use in bridge-to-transplant patients and is under investigation for destination therapy. To avoid device-related thromboembolic complications, antiplatelet, and anticoagulation therapy are routinely administered. A worrisome frequency of gastrointestinal (GI) bleeding events has been observed., Methods: A retrospective review of all 33 patients undergoing long-term LVAD implantation between June 1, 2006 and July 31, 2008 at our institution for any indication was conducted. Anticoagulation consisted of heparin (intravenous or subcutaneous) followed by transition to Coumadin therapy to a target INR of two to three. Antiplatelet therapy consisted of low-dose aspirin and dipyridamole., Results: Twenty patients received the HMII and 13 patients received other devices. Eight (40%) HMII recipients suffered at least one episode of GI bleeding while no GI bleeding occurred in recipients of other devices (p = 0.012). Of 17 total bleeding episodes, no definitive source could be identified in 11 instances (65%)., Conclusions: Although definitive source identification remains elusive, we believe that the majority of bleeding arises in the small bowel, possibly due to angiodysplasias, similar to the pathophysiology encountered in patients with aortic stenosis and GI bleeding. As we move toward wider use of the HMII and other axial continuous-flow devices in both bridge-to-transplant patients and for destination therapy, more studies will be necessary to understand the mechanisms of this obscure GI bleeding and develop treatment strategies to minimize its development.

Aim: Laparoscopy is an increasingly important tool in the staging and treatment for potentially resectable liver metastases. The clinical risk score (CRS) is useful in selecting patients for diagnostic laparoscopy before planning resection of colorectal metastases. This study evaluates the effect of staging laparoscopy (SL) combined with CRS., Materials and Methods: From January 2004 to December 2007, CRS evaluation and SL were performed in 65 consecutive patients with colorectal metastases, before planned open-exploration and resection. Patients were assigned to a CRS, which is based on 5 factors related to the primary tumor and the hepatic disease. This study was aimed at recognizing occult unresectable metastases, by combining laparoscopy and CRS., Results: Only 62 patients had a complete SL examination (3 were excluded for dense adhesions). A group of 24 patients was identified as unresectable, and 38 patients as resectable. In the latter group, 3 patients directly had laparoscopic treatment. In all, 38 patients underwent laparotomy (35 resectable, and 3 patients with dense adhesions that could not have a complete laparoscopic treatment).Resection was carried out in 30 of 38 (78.9%) cases, and the remaining 21% gave false-negative results. In all, there were 32 of 65 (49.2%) unresectable patients, and 75% of them were recognized by SL., Conclusions: Laparoscopy identified the majority of patients with occult unresectable disease, improved resectability, and it should be a routine in patients being considered for potentially curative hepatic resection. The CRS, earlier shown to predict survival after hepatic resection, identifies high-risk patients, who are most likely to benefit from laparoscopy, and may improve resource utilization.

Rationale: Chronic rejection, accelerated coronary atherosclerosis, myocardial infarction, and ischemic heart failure determine the unfavorable evolution of the transplanted heart in humans., Objective: Here we tested whether the pathological manifestations of the transplanted heart can be corrected partly by a strategy that implements the use of cardiac progenitor cells from the recipient to repopulate the donor heart with immunocompatible cardiomyocytes and coronary vessels., Methods and Results: A large number of cardiomyocytes and coronary vessels were created in a rather short period of time from the delivery, engraftment, and differentiation of cardiac progenitor cells from the recipient. A proportion of newly formed cardiomyocytes acquired adult characteristics and was integrated structurally and functionally within the transplant. Similarly, the regenerated arteries, arterioles, and capillaries were operative and contributed to the oxygenation of the chimeric myocardium. Attenuation in the extent of acute damage by repopulating cardiomyocytes and vessels decreased significantly the magnitude of myocardial scarring preserving partly the integrity of the donor heart., Conclusions: Our data suggest that tissue regeneration by differentiation of recipient cardiac progenitor cells restored a significant portion of the rejected donor myocardium. Ultimately, immunosuppressive therapy may be only partially required improving quality of life and lifespan of patients with cardiac transplantation.

Objective: : The education of patients in the informed consent process remains a challenge for many surgeons. In cardiothoracic surgery, emerging minimally invasive techniques including robotics add another level of complexity to the patient education process. We sought to evaluate our patients' perceptions and informed knowledge after robotic-assisted cardiothoracic surgery., Methods: : A survey containing questions designed to elicit patients' perceptions about robotic cardiothoracic surgery was given postoperatively by telephone 1 month to 12 months after surgery. The survey included questions about the type of procedure, function of the organ operated on, purpose of the operation, primary "surgeon" (robot vs. human), patients' opinion about robotic-assisted surgery, educational level, and socioeconomic background. Continuous variables are reported as mean ± SD. Continuous and categorical variables were compared using the Student t test and Pearson χ test, respectively. Ordinal variables were compared using the Mann-Whitney U test. P values of <0.05 were considered significant., Results: : Between 2002 and 2007, 198 patients underwent robotic cardiothoracic surgery. One hundred fifty patients (76%) were contacted and 89 (45%) fully completed the survey. Of the respondents, there were 31 coronary artery bypasses, 33 pacemaker lead implantations, esophageal resections, 8 thymectomies, and 9 others. The mean age of the patients was 61.1 ± 15 years (range, 23-87) and there were 52 men (58.4%). A total of 96.6% of patients were satisfied with the information provided by the surgeon and 92.1% felt that they understood the information. The diagnosis, target organ, and procedure were correctly identified by 81 (91.0%), 83 (93.3%), and 76 (85.4%) of the patients, respectively. A total of 80 (89.9%) knew a robot was involved and 73.8% understood the role of the robot in the surgery. These results were independent of age, income, and education level achieved., Conclusions: : Overall, patients demonstrated an understanding of the role of the robot in their cardiothoracic surgery. Despite the increasing complexity of robotics, preoperative patient education can result in patients who are both satisfied and well educated about their cardiothoracic surgery procedures.

Primitive cells capable of generating small resistance arterioles and capillary structures in the injured myocardium have been identified repeatedly. However, these cells do not form large conductive coronary arteries that would have important implications in the management of the ischemic heart. In the current study, we determined whether the human heart possesses a class of progenitor cells that regulates the growth of endothelial cells (ECs) and smooth muscle cells (SMCs) and vasculogenesis. The expression of vascular endothelial growth-factor receptor 2 (KDR) was used, together with the stem cell antigen c-kit, to isolate and expand a resident coronary vascular progenitor cell (VPC) from human myocardial samples. Structurally, vascular niches composed of c-kit-KDR-positive VPCs were identified within the walls of coronary vessels. The VPCs were connected by gap junctions to ECs, SMCs, and fibroblasts that operate as supporting cells. In vitro, VPCs were self-renewing and clonogenic and differentiated predominantly into ECs and SMCs and partly into cardiomyocytes. To establish the functional import of VPCs, a critical stenosis was created in immunosuppressed dogs, and tagged human VPCs were injected in proximity to the constricted artery. One month later, there was an increase in coronary blood flow (CBF) distal to the stenotic artery, resulting in functional improvement of the ischemic myocardium. Regenerated large, intermediate, and small human coronary arteries and capillaries were found. In conclusion, the human heart contains a pool of VPCs that can be implemented clinically to form functionally competent coronary vessels and improve CBF in patients with ischemic cardiomyopathy.

Objective: The aim of this study was to evaluate the biocompatibility of the root canal sealer Epiphany in rat subcutaneous tissues., Study Design: Polyethylene tubes were filled with the sealer (I: Epiphany; II: photoactivated Epiphany; III: Epiphany associated with self-etch primer; IV: photoactivated Epiphany associated with primer; and V: control group) and later implanted into 4 different regions of the dorsum of 15 adult male rats (Rattus novergicus, Albinus Wistar). After 7, 21, and 42 days, 5 animals were killed, obtaining 4 samples per group, in addition to the control group, at each analyzed time., Results: In all periods, Epiphany induced a mild inflammatory reaction. However, in group II, in which the primer was not used, extensive necrosis and a moderate to intense inflammatory reaction were observed, mainly after 7 and 21 days., Conclusion: Epiphany sealer appears biocompatible when tested on rat subcutaneous tissues.

The identification of cardiac progenitor cells in mammals raises the possibility that the human heart contains a population of stem cells capable of generating cardiomyocytes and coronary vessels. The characterization of human cardiac stem cells (hCSCs) would have important clinical implications for the management of the failing heart. We have established the conditions for the isolation and expansion of c-kit-positive hCSCs from small samples of myocardium. Additionally, we have tested whether these cells have the ability to form functionally competent human myocardium after infarction in immunocompromised animals. Here, we report the identification in vitro of a class of human c-kit-positive cardiac cells that possess the fundamental properties of stem cells: they are self-renewing, clonogenic, and multipotent. hCSCs differentiate predominantly into cardiomyocytes and, to a lesser extent, into smooth muscle cells and endothelial cells. When locally injected in the infarcted myocardium of immunodeficient mice and immunosuppressed rats, hCSCs generate a chimeric heart, which contains human myocardium composed of myocytes, coronary resistance arterioles, and capillaries. The human myocardium is structurally and functionally integrated with the rodent myocardium and contributes to the performance of the infarcted heart. Differentiated human cardiac cells possess only one set of human sex chromosomes excluding cell fusion. The lack of cell fusion was confirmed by the Cre-lox strategy. Thus, hCSCs can be isolated and expanded in vitro for subsequent autologous regeneration of dead myocardium in patients affected by heart failure of ischemic and nonischemic origin.

Twenty-five subjects suffering from Panic Disorder with agoraphobia (PDA) and 25 normal controls (NC) were asked to estimate distances of familiar places of their town and non-distance stimuli. PDA subjects also completed the Mobility Inventory for Agoraphobia (MIA). Subjects with PDA significantly overestimated distances as compared to NC, whereas no significant difference was found on estimates of non-distance stimuli. Within the PDA group, significant correlations were found between distance estimates and subsets of MIA concerning the ways of moving through the environment. Although with caution, given the small sample size and the preliminary character of this study, the results could be interpreted as consistent with a cognitive dysfunction associated with PDA, probably at the level of representational mechanisms of the extrapersonal space.

The widespread success of living renal transplantation has given the medical community both the opportunity and the responsibility of establishing social and ethical guidelines for the protection of donors and the treatment of recipients. While the prospects of treating more patients with organ transplant is exciting, the demand still far outpaces the supply. It is the responsibility of the transplant community and individual transplant centers to maintain a high level of integrity and ethical practice so that living renal transplantation can continue to be a viable and effective treatment for renal failure.

Investigation techniques for karst flow systems are based mainly on the study of different signals leaving the system caused by natural or induced external influences. Each signal represents one of the systems outputs (e.g., hydraulic, chemical, physical, or isotopic responses) that reflect the characteristics of the entire system. In this paper, we present a method to infer information about the structure of karst systems. It is based on a simultaneous analysis of chemical and hydraulic responses. Beside the classical piston flow at the beginning of a flood pulse, we define a chemically based recession flow phase. During this phase, field data show that the concentration of total dissolved solids can be considered as an exponential function of the logarithm of flow. This relationship allows two parameters to be defined, one of which is dependent on the structure and degree of development of the karst conduit network, the other is dependent mainly on bioclimatic factors. Data collected from seven karst springs are used to support ideas introduced in the paper.

Right sided circulatory failure (RSCF), a common complication after left ventricular assist device (LVAD) implantation, results in decreased systemic output due to diminished blood flow across the pulmonary vasculature. The authors hypothesized that creation of a venoarterial shunt (VAS) would decompress the right-sided circulation and improve systemic pressure and perfusion with significant arterial desaturation. An experimental model was created in which RSCF was induced acutely in a large animal (n = 6) by beta-blockade after LVAD placement. After VAS creation, hemodynamic and blood gas determinations were performed to compare non shunt and shunt states. After induction of heart failure after LVAD placement, VAS resulted in a 22% elevation in systemic blood pressure (p < 0.0001), a 36% elevation in cerebral blood flow (p = 0.02), and an 18% decrease in right sided filling pressures (p = 0.08). Systemic pH and aortic oxygen saturation remained unchanged from baseline. In a large animal model of RSCF after LVAD implantation, VAS improves systemic hemodynamics without a significant cost in arterial oxygenation to critical organs and without creating acid-base imbalance. Beside implementation, adjustable capabilities, easy removal and salutatory hemodynamic effects suggest that VAS may serve as a first line, short-term therapy for LVAD recipients who develop perioperative RSCF.

Continuous measurement of cardiac output is important during experimental and clinical cardiac surgery as an indicator of ventricular function. Previous flow probes underestimated flow secondary to position and flow (S-series probes; Transonic Systems, Inc., Ithaca, NY), required frequent calibrations (electromagnetic), and were cumbersome to use. The new A-series probe (ASP) by Transonic Systems, Inc., uses a new X method of ultrasonic illumination insensitive to perturbations in flow. The ASPs were found to be accurate during in vitro studies, but have not been validated in vivo. Six anesthetized pigs were instrumented for right atrium to left atrium bypass, and ASPs were placed on the ascending aorta and pulmonary artery. Baseline measurements included aortic (Ao) and pulmonic flow (P), and thermodilution (Td) cardiac output. Animals then were placed on right heart bypass, and flow was randomly varied from 1 to 6 L/min, and Ao flow was recorded. In addition, ASPs were rotated and their direction reversed. After data collection, the occlusive roller pump (RP) was calibrated using a timed collection method. Calibrated RP flows were plotted versus ASP flows, and regression was applied. There was no difference between mean Ao, P, and Td cardiac outputs at baseline. In addition, changes in position and direction of the probe did not affect measurement of flow. The ASPs showed a highly linear correlation with RP ([r = 0.98, p < 0.01] ASP[L/min] = 0.98 RP-0.032). During laminar flow states, ASPs are accurate and insensitive to position on the great vessels.