Development of in vitro microfluidic models to study endothelial responses to pulsatility with different mechanical circulatory support devices.

Continuous-flow ventricular assist devices (CFVAD) and counterpulsation devices (CPD) are used to treat heart failure (HF). CFVAD can diminish pulsatility, but pulsatile modes have been implemented to increase vascular pulsatility. The effects of CFVAD in a pulsatile mode and CPD support on the function of endothelial cells (ECs) are yet to be investigated. In this study, two in vitro microfluidic models for culturing ECs are proposed to reproduce blood pressure (BP) and wall shear stress (WSS) on the arterial endothelium while using these medical devices. The layout and parameters of the two microfluidic systems were optimized based on the principle of hemodynamic similarity to efficiently simulate physiological conditions. Moreover, the unique design of the double-pump and double afterload systems could successfully reproduce the working mode of CPDs in an in vitro microfluidic system. The performance of the two systems was verified by numerical simulations and in vitro experiments. BP and WSS under HF, CFVAD in pulsatile modes, and CPD were reproduced accurately in the systems, and these induced signals improved the expression of Ca2+, NO, and reactive oxygen species in ECs, proving that CPD may be effective in normalizing endothelial function and replacing CFVAD to a certain extent to treat non-severe HF. This method offers an important tool for the study of cell mechanobiology and a key experimental basis for exploring the potential value of mechanical circulatory support devices in reducing adverse events and improving outcomes in the treatment of HF in the future.

Clinical Outcomes and Quality of Life With an Ambulatory Counterpulsation Pump in Advanced Heart Failure Patients: Results of the Multicenter Feasibility Trial.

BACKGROUND: The NuPulseCV intravascular ventricular assist system (iVAS) provides extended duration ambulatory counterpulsation via a durable pump placed through the distal subclavian artery. METHODS: We performed a prospective, single-arm, multicenter, US Food and Drug Administration-approved feasibility trial of iVAS therapy as a bridge to transplant or decision following the FIH (First-In-Human) trial. RESULTS: Forty-seven patients were enrolled, and 45 patients (median 61 years old, 37 males, and 30 listed on United Network of Organ Sharing) received iVAS support for median 44 (25-87) days. There were no intraoperative complications. Success was defined as survival or transplant on iVAS therapy free from disabling stroke. Outcome success at 30 days (the primary end point of this study) and at 6 months was 89% and 80%, respectively. During 6 months of iVAS support, 2 patients died and 2 patients experienced disabling neurological dysfunction. Six-minute walk distance, 2-minute step test, and Kansas City Cardiomyopathy Questionnaire score improved during 4-week iVAS support. CONCLUSIONS: This feasibility trial demonstrated promising short-term outcomes of iVAS therapy with improved functional capacity and quality of life during the therapy. Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02645539.

Preload Sensitivity with TORVAD Counterpulse Support Prevents Suction and Overpumping.

PURPOSE: This study compares preload sensitivity of continuous flow (CF) VAD support to counterpulsation using the Windmill toroidal VAD (TORVAD). The TORVAD is a two-piston rotary pump that ejects 30 mL in early diastole, which increases cardiac output while preserving aortic valve flow. METHODS: Preload sensitivity was compared for CF vs. TORVAD counterpulse support using two lumped parameter models of the cardiovascular system: (1) an open-loop model of the systemic circulation was used to obtain ventricular function curves by isolating the systemic circulation and prescribing preload and afterload boundary conditions, and (2) a closed-loop model was used to test the physiological response to changes in pulmonary vascular resistance, systemic vascular resistance, heart rate, inotropic state, and blood volume. In the open-loop model, ventricular function curves (cardiac output vs left ventricular preload) are used to assess preload sensitivity. In the closed-loop model, left ventricular end systolic volume is used to assess the risk of left ventricular suction. RESULTS: At low preloads of 5 mmHg, CF support overpumps the circulation compared to TORVAD counterpulse support (cardiac output of 3.3 L/min for the healthy heart, 4.7 with CF support, and 3.5 with TORVAD counterpulse support) and has much less sensitivity than counterpulse support (0.342 L/min/mmHg for the healthy heart, 0.092 with CF support, and 0.306 with TORVAD counterpulse support). In the closed-loop model, when PVR is increased beyond 0.035 mmHg s/mL, CF support overpumps the circulation and causes ventricular suction events, but TORVAD counterpulse support maintains sufficient ventricular volume and does not cause suction. CONCLUSIONS: Counterpulse support with the TORVAD preserves aortic valve flow and provides physiological sensitivity across all preload conditions. This should prevent overpumping and minimize the risk of suction.

Salutary Effects of the PULVAD, a Novel Implantable Counterpulsation Assist Device, on Cardiac Mechanoenergetics.

The Pressure Unloading Left Ventricular Assist Vevice (PULVAD) is a novel implantable counterpulsation LVAD, designed to provide ventricular unloading with augmentation of LV performance and retention of pulsatility. We assessed the effects of the PULVAD on hemodynamics and LV mechanoenergetics in seven farm pigs with acute ischemic heart failure. The PULVAD was implanted in the thorax and was connected to the ascending aorta. The PULVAD was pneumatically driven by a standard intra-aortic balloon pump console and was electrocardiogram-synchronized to provide LV pressure unloading along with diastolic aortic pressure augmentation. Hemodynamics, indices of LV mechanoenergetics, and coronary blood flow were measured without and after brief PULVAD support. PULVAD support decreased LV afterload and improved LV mechanical performance (increased ejection fraction, stroke volume, cardiac output and maximum elastance). The PULVAD concurrently reduced LV energy consumption (decreased stroke work and pressure-volume area) and optimized LV energetic performance (improved the ratio of stroke work to pressure-volume area). PULVAD support increased mean coronary blood flow, through dramatic augmentation of diastolic blood flow. In conclusion, the PULVAD unloads the failing LV, optimizes LV mechanoenergetics, and augments coronary blood flow. These salutary effects of short-term PULVAD support provide the foundation for long-term testing.

Improvement in Biventricular Cardiac Function After Ambulatory Counterpulsation.

BACKGROUND: The NupulseCV intravascular ventricular assist system (iVAS), which consists of a durable pump placed through the subclavian artery, provides extended-duration ambulatory counterpulsation. This study investigated the effect of iVAS on biventricular cardiac function. METHODS AND RESULTS: We reviewed all heart failure patients who received iVAS implantation as a bridge to transplantation or a bridge to candidacy since April 2016 as part of the iVAS first-in-humans and subsequent feasibility study. We compared data of transthoracic echocardiography performed just before implantation (without iVAS support) and again at 30 days or just before explantation (on iVAS support). Eighteen patients (58.8 ± 7.4 years old and 15 male) received iVAS support for 53 ± 43 days. Fourteen patients were bridged to cardiac replacement therapy after 35 ± 19 days and the remaining 4 patients had been supported for 118 ± 41 days. There were no deaths during iVAS support. At 30 days, there was a significant improvement in left ventricular ejection fraction (16.5% ± 11.9% vs 24.4% ± 12.8%; P = .007) and marked reduction in left atrial size (62.7 ± 35.7 mL/m2 vs 33.8 ± 17.2 mL/m2; P < .001). Right ventricular fractional area change improved dramatically (25.4% ± 12.9% vs 42.1% ± 12.4%; P < .001). All other right ventricular and right atrial parameters improved significantly as well (size, tricuspid annular plane systolic excursion, and velocity of tricuspid annular systolic motion). CONCLUSIONS: Improvement in biventricular cardiac function was observed after 30 days of iVAS support. Further studies should examine the use of this technology as a bridge to recovery.

Effects of enhanced external counterpulsation on skeletal muscle gene expression in patients with severe heart failure.

Enhanced external counterpulsation (EECP) is a non-invasive treatment in which leg cuff compressions increase diastolic aortic pressure and coronary perfusion. EECP is offered to patients with refractory angina pectoris and increases physical capacity. Benefits in heart failure patients have been noted, but EECP is still considered to be experimental and its effects must be confirmed. The mechanism of action is still unclear. The aim of this study was to evaluate the effect of EECP on skeletal muscle gene expression and physical performance in patients with severe heart failure. Patients (n = 9) in NYHA III-IV despite pharmacological therapy were subjected to 35 h of EECP during 7 weeks. Before and after, lateral vastus muscle biopsies were obtained, and functional capacity was evaluated with a 6-min walk test. Skeletal muscle gene expression was evaluated using Affymetrix Hugene 1.0 arrays. Maximum walking distance increased by 15%, which is in parity to that achieved after aerobic exercise training in similar patients. Skeletal muscle gene expression analysis using Ingenuity Pathway Analysis showed an increased expression of two networks of genes with FGF-2 and IGF-1 as central regulators. The increase in gene expression was quantitatively small and no overlap with gene expression profiles after exercise training could be detected despite adequate statistical power. EECP treatment leads to a robust improvement in walking distance in patients with severe heart failure and does induce a skeletal muscle transcriptional response, but this response is small and with no significant overlap with the transcriptional signature seen after exercise training.

Hemodynamic Benefits of Counterpulsation, Implantable, Percutaneous, and Intraaortic Rotary Blood Pumps: An In-Silico and In Vitro Study.

Mechanical circulatory support (MCS) devices have become a standard therapy for heart failure (HF) patients. MCS device designs may differ by level of support, inflow and/or outflow cannulation sites, and mechanism(s) of cardiac unloading and blood flow delivery. Investigation and direct comparison of hemodynamic parameters that help characterize performance of MCS devices has been limited. We quantified cardiac and vascular hemodynamic responses for different types of MCS devices. Continuous flow (CF) left ventricular (LV) assist devices (LVAD) with LV or left atrial (LA) inlet, counterpulsation devices, percutaneous CF LVAD, and intra-aortic rotary blood pumps (IARBP) were quantified using established computer simulation and mock flow loop models. Hemodynamic data were analyzed on a beat-to-beat basis at baseline HF and over a range of MCS support. Results demonstrated that all LVAD greatly diminished vascular pulsatility (P) and LV external work (LVEW). LVAD with LA inflow provided a greater reduction in LVEW compared to LVAD with LV inflow, but at the potential risk for blood stasis/thrombosis in the LV at high support. Counterpulsation provided greater coronary flow (CoF) augmentation, but had a lower reduction in LVEW compared to partial percutaneous LVAD support. IARBP diminished LVEW, but at the expense of diminished CoF due to coronary steal. The hemodynamic benefits for each type of mechanical circulatory support system are unique and clinical decisions on device selection to maximize end organ perfusion and minimize invasiveness needs to be considered for an individual patients' presentation.

Hemodynamic Impact of the C-Pulse Cardiac Support Device: A One-Dimensional Arterial Model Study.

The C-Pulse is a novel extra-aortic counter-pulsation device to unload the heart in patients with heart failure. Its impact on overall hemodynamics, however, is not fully understood. In this study, the function of the C-Pulse heart assist system is implemented in a one-dimensional (1-D) model of the arterial tree, and central and peripheral pressure and flow waveforms with the C-Pulse turned on and off were simulated. The results were studied using wave intensity analysis and compared with in vivo data measured non-invasively in three patients with heart failure and with invasive data measured in a large animal (pig). In all cases the activation of the C-Pulse was discernible by the presence of a diastolic augmentation in the pressure and flow waveforms. Activation of the device initiates a forward traveling compression wave, whereas a forward traveling expansion wave is associated to the device relaxation, with waves exerting an action in the coronary and the carotid vascular beds. We also found that the stiffness of the arterial tree is an important determinant of action of the device. In settings with reduced arterial compliance, the same level of aortic compression demands higher values of external pressure, leading to stronger hemodynamic effects and enhanced perfusion. We conclude that the 1-D model may be used as an efficient tool for predicting the hemodynamic impact of the C-Pulse system in the entire arterial tree, complementing in vivo observations.

Terapias percutáneas en el tratamiento de la insuficiencia cardiaca aguda y crónica: presente y futuro / Current and future percutaneous strategies for the treatment of acute and chronic heart failure

La prevalencia de la insuficiencia cardiaca (IC) aumenta paralelamente al envejecimiento poblacional y la mayor supervivencia de los pacientes con infarto de miocardio. Recientemente se han desarrollado nuevas terapias percutáneas con el objetivo de complementar los tratamientos actuales de la IC aguda/descompensada y crónica minimizando los riesgos. En la IC aguda, el fracaso del tratamiento médico ya no puede ser el final de la estrategia terapeútica para el shock cardiogénico, dado el éxito de los dispositivos de soporte circulatorio mecánico. A pesar de que la evidencia en esta área es difícil de generar, el pronóstico de la IC aguda está cambiando radicalmente gracias a la investigación en red sobre dispositivos de flujo pulsátil (balón de contrapulsación intraaórtico), continuo axial (Impella) o continuo centrífugo (TandemHeart; HeartMate PHP) junto con el implante percutáneo de oxigenador extracorpóreo de membrana. Las nuevas terapias percutáneas en la IC crónica se basan en atractivas hipótesis como la descompresión de la aurícula izquierda (shunts), la restauración ventricular (compartimentación) o la monitorización intratorácica de presiones mediante dispositivos implantables que permitan tratar precozmente las descompensaciones. Actualmente solo la última se ha probado efectiva en un estudio aleatorizado. Por lo tanto, es necesario estudiar a fondo este dinámico y prometedor campo (AU)

The prevalence of heart failure (HF) has risen in parallel with improved survival in patients after a myocardial infarction and an aging population worldwide. In recent years, new percutaneous therapies have been developed to complement current established treatments for acute/decompensated and chronic HF and minimize risks. In acute presentations, the failure of medical treatment is no longer the end of the road in refractory circulatory shock; the use of mechanical circulatory support devices may be the next milestone in well-resourced health settings. Although evidence in this area is difficult to generate, research networks can facilitate the volume and quality of data needed to further augment the clinician's knowledge. Pulsatile (intra-aortic balloon pump), axial continuous (Impella), or centrifugal continuous pumps (TandemHeart; HeartMate PHP) together with percutaneously implanted extracorporeal membrane oxygenation are radically changing the prognosis of acute HF. Newer percutaneous therapies for chronic HF are based on attractive hypotheses, including left atrial decompression with shunting devices, left ventricle restoration through partitioning devices, or pressure-guided implantable therapies that may help to promptly treat decompensations. To date, only the last has been proved effective in a randomized study. Therefore, thorough research is still needed in this dynamic and promising field (AU)

Efficacy of Subcutaneous Electrocardiogram Leads for Synchronous Timing During Chronic Counterpulsation Therapy.

Counterpulsation devices (CPDs) require an accurate, reliable electrocardiogram (ECG) waveform for triggering inflation and deflation. Surface electrodes are for short-term use, and transvenous/epicardial leads require invasive implant procedure. A subcutaneous ECG lead configuration was developed as an alternative approach for long-term use with timing mechanical circulatory support (MCS) devices. In this study, efficacy testing was completed by simultaneously recording ECG waveforms from clinical-grade epicardial (control) and subcutaneous (test) leads in chronic ischemic heart failure calves implanted with CPD for up to 30 days. Sensitivity and specificity of CPD triggering by R-wave detection was quantified for each lead configuration. The subcutaneous leads provided 98.9% positive predictive value and 98.9% sensitivity compared to the epicardial ECG leads. Lead migration (n = 1) and fracture (n = 1) were observed in only 2 of 40 implanted leads, without adversely impacting triggering efficacy due to lead redundancy. These findings demonstrate the efficacy of subcutaneous ECG leads for long-term CPD timing and potential use as an alternative method for MCS device timing.

Sunshine Heart C-Pulse: device for NYHA Class III and ambulatory Class IV heart failure.

Advanced heart failure (HF) patients not meeting criteria for ventricular assist device or heart transplant with life-limiting symptoms are limited to medical and resynchronization therapy. The Sunshine Heart C-Pulse, based on intra-aortic balloon pump physiology, provides implantable, on-demand, extra-aortic counterpulsation, which reduces afterload and improves cardiac perfusion in New York Heart Association Class III and ambulatory Class IV HF. The C-Pulse reduces New York Heart Association Class, improves 6-min walk distances, inotrope requirements and HF symptom questionnaires. Advantages include shorter operative times without cardiopulmonary bypass, no reported strokes or thrombosis and no need for anticoagulation. Driveline exit site infections, inability to provide full circulatory support and poor function with intractable arrhythmias remain concerns. Current randomized controlled studies will evaluate long-term efficacy and safety compared with medical and resynchronization therapy.

RheoStim: Development of an Adaptive Multi-Sensor to Prevent Venous Stasis.

Chronic venous insufficiency of the lower limbs is often underestimated and, in the absence of therapy, results in increasingly severe complications, including therapy-resistant tissue defects. Therefore, early diagnosis and adequate therapy is of particular importance. External counter pulsation (ECP) therapy is a method used to assist the venous system. The main principle of ECP is to squeeze the inner leg vessels by muscle contractions, which are evoked by functional electrical stimulation. A new adaptive trigger method is proposed, which improves and supplements the current therapeutic options by means of pulse synchronous electro-stimulation of the muscle pump. For this purpose, blood flow is determined by multi-sensor plethysmography. The hardware design and signal processing of this novel multi-sensor plethysmography device are introduced. The merged signal is used to determine the phase of the cardiac cycle, to ensure stimulation of the muscle pump during the filling phase of the heart. The pulse detection of the system is validated against a gold standard and provides a sensitivity of 98% and a false-negative rate of 2% after physical exertion. Furthermore, flow enhancement of the system has been validated by duplex ultrasonography. The results show a highly increased blood flow in the popliteal vein at the knee.

Preliminary Results From the C-Pulse OPTIONS HF European Multicenter Post-Market Study.

BACKGROUND The C-Pulse System is an extra-aortic balloon counterpulsation device. It is used to treat patients with heart failure disease in NYHA functional class III or ambulatory class IV. MATERIAL AND METHODS We present preliminary site-reported 6-month data from 3 centers in Germany as part of the prospective observational post-market OPTIONS HF study. RESULTS Between May 2013 and March 2014, the C-Pulse System was implanted in 8 patients (7 male) with a mean age of 61.6±9.3 years. Four had ischemic and 4 had non-ischemic cardiomyopathy. No stroke, myocardial infarction, major bleeding, or major infection due to the device were reported. One patient developed non-device-related refractory tachycardia with worsening heart failure 12 h after surgery and underwent left ventricular assist device implantation. Within 6 months of observation, functional status improved from NYHA III to II in 5 patients, and 2 remained in NYHA III. Mean left ventricular ejection fraction increased from 24.3±7.9% to 44.5±4.5% (p<0.0001). Mean Kansas City Cardiomyopathy Questionnaire overall score improved from 28.6±19.1 to 59.1±22.5 (p=0.0183). Six-minute walk test was performed in 6 out of 7 patients at follow-up. The mean distance improved from 252.0±85.1 m to 279.2±87.5 m (p>0.05). One patient was weaned off the device after 6 months of support. CONCLUSIONS The C-Pulse System provides a therapeutic option for patients with moderate-to-severe heart failure and seems to improve quality of life and cardiac function over time.

Extended extra-aortic counterpulsation with the C-Pulse device does not alter aortic wall structure.

The C-Pulse System is an implantable, extra-aortic, non-blood-contacting counterpulsation device, investigational in the United States and intended for use as a heart assist device for heart failure (NYHA class III-ambulatory IV) patients. As long-term effects of this implantable extra-aortic counterpulsation device on the aortic wall structure are not well established, we examined the histological and clinical data of a patient supported on the device for 21 months. A 58-year-old woman diagnosed with nonischemic cardiomyopathy (NYHA III) remained symptomatic despite optimal medical therapy and dual chamber pacemaker. She was listed for heart transplant, and a C-Pulse device was implanted. One month after implantation, her symptoms improved from NYHA class III to class I, and her cardiac output increased from 3.5 to 5.5 L/min. She received a heart transplant 21 months after device implantation. Tissue samples from her ascending aorta were obtained. They appeared normal on macroscopic examination. Microscopic examination revealed a normal intima and media, with no disruption; a mild neutrophilic inflammation was noted on the adventitia. Extended extra-aortic counterpulsation with the C-Pulse device provided hemodynamics and symptoms improvement in a class III heart failure patient and does not appear to significantly alter aortic wall structures.

Novel external counterpulsation system, compact counterpulsation, was effective to treat severe ischemic heart failure: a case report.

Compact counterpulsation (CP) is a novel external counterpulsation system. The preoperative clinical utility of compact CP therapy in patients has not been established. In the present report, we describe a case wherein compact CP therapy was successfully used to treat severe ischemic heart failure. A 70-year-old man was diagnosed with ischemic heart disease and mitral valve regurgitation at 61 years of age. Therefore, he underwent coronary artery bypass and mitral valve plasty. The patient's condition started to gradually deteriorate at 68 years of age, and he became progressively dependent on catecholamine support. Mitral valve regurgitation recurred, which caused worsening of heart function. Before a mitral valve replacement, the patient had been treated with compact CP therapy to improve heart function and general condition. The patient's clinical condition improved with compact CP therapy after only ten sessions; in addition, he could be weaned off catecholamine support. No adverse effects were observed, and therefore, he could complete the CP therapy as an outpatient. Mitral valve replacement was performed after a total of 44 sessions. The patient had an uneventful postoperative course and was discharged on the 18th postoperative day. Compact CP therapy was thus performed on our patient without any discomfort and appears to be an effective treatment for patients with severe ischemic heart failure.

Counterpulsation: a concept with a remarkable past, an established present and a challenging future.

The intra-aortic balloon pump (IABP), which is the main representative of the counterpulsation technique, has been an invaluable tool in cardiologists' and cardiac surgeons' armamentarium for approximately half a century. The IABP confers a wide variety of vaguely understood effects on cardiac physiology and mechano-energetics. Although, the recommendations for its use are multiple, most are not substantially evidence-based. Indicatively, the results of recently performed prospective studies have put IABP's utility in the setting of post-infarction cardiogenic shock into question. However, the particular issue remains open to further research. IABP support in high-risk patients undergoing PCI is associated with favorable long-term clinical outcome. In cardiac surgery, the use of IABP in cases of peri-operative low-output syndrome, refractory angina or ischemia-related mechanical complications is a usual, but poorly justified strategy. Anecdotal cases of treatment of incessant ventricular arrhythmias, reversal of right ventricular dysfunction and partial myocardial recovery have also been reported with its use. Converging data demonstrate the potential of safe long-term IABP support as a bridge to decision making or a bridge to transplantation modality in patients with heart failure. The feasibility of IABP insertion via other than the femoral artery sites enhances this potential. Despite the fact that several other counterpulsation devices have been developed and tested overtime none has managed to substitute the IABP, which continues to be most frequently used mechanical assist device.

Aortic counterpulsation: C-pulse and other devices for cardiac support.

Heart failure is the leading cause of hospitalization in the USA. Despite major advances in the medical and device-related therapy including chronic resynchronization therapy for management of heart failure, significant number of patients eventually require advanced cardiac therapy including mechanical circulatory support or heart transplant. Heart transplant is a gold standard for end-stage heart failure but is limited by the donor heart shortage creating a definite need for alternative effective therapies. The earliest and most common form of mechanical circulatory support is counterpulsation therapy. Annually, more than 150,000 patients worldwide receive counterpulsation therapy for various indications including cardiogenic shock or severe left ventricular dysfunction (Nanas and Moulopoulos in Cardiology, 84:156-167, 1994) and many thousands of lives are saved each year (65 % survival) (Torchiana et al. in Journal of Thoracic and Cardiovascular Surgery, 113(4):758-764, 1997). There are different types of aortic counterpulsation devices. Here, we will give an overview of different counterpulsation devices with focus on C-Pulse device. Extra-aortic balloon counterpulsation, C-Pulse (Sunshine Heart Inc., Eden Prairie, MN), is an important and novel approach in the management of patients with advanced heart failure who remain symptomatic despite optimum medical and device-based therapy. C-Pulse is designed to provide permanent, long-term, continuous partial circulatory support for New York Heart Association class III and ambulatory class IV heart failure patients. C-Pulse is a nonblood-contacting counterpulsation using an inflatable cuff around the ascending aorta, extra-aortic balloon (EAB) counterpulsation device. A pivotal, multicenter US study to assess the safety and efficacy of C- Pulse in patient with Stage C and NYHA Class III or ambulatory Class IV heart failure is in progress.

Novel control system to prevent right ventricular failure induced by rotary blood pump.

Right ventricular (RV) failure is a potentially fatal complication after treatment with a left ventricular assist device (LVAD). Ventricular septal shift caused by such devices is an important factor in the progress of RV dysfunction. We developed a control system for a rotary blood pump that can change rotational speed (RS) in synchrony with the cardiac cycle. We postulated that decreasing systolic RS using this system would alter ventricular septal movement and thus prevent RV failure. We implanted the EVAHEART ventricular assist device into seven adult goats weighing 54.1 ± 2.1 kg and induced acute bi-ventricular dysfunction by coronary embolization. Left and RV pressure was monitored, and ventricular septal movement was echocardiographically determined. We evaluated circuit-clamp mode as the control condition, as well as continuous and counter-pulse modes, both with full bypass. As a result, a leftward ventricular septal shift occurred in continuous and counter-pulse modes. The septal shift was corrected as a result of decreased RS during the systolic phase in counter-pulse mode. RV fractional area change improved in counter-pulse (59.0 ± 4.6%) compared with continuous (44.7 ± 4.0%) mode. In conclusion, decreased RS delivered during the systolic phase using the counter-pulse mode of our new system holds promise for the clinical correction of ventricular septal shift resulting from a LVAD and might confer a benefit upon RV function.