Novel ECG-Synchronized Pulsatile ECLS System With Various Heart Rates and Cardiac Arrhythmias: An In Vitro Study *Shigang Wang, *Shannon B. Spencer, †Allen R. Kunselman, and *‡Akif € Undar *Department of Pediatrics, Public Health and Sciences, Penn State Hershey Pediatric Cardiovascular Research Center; †Public Health and Sciences; ‡Surgery and Bioengineering, Penn State Hershey College of Medicine, Penn State Milton S. Hershey Medical Center, Penn State Hershey Children’s Hospital, Hershey, PA, USA Abstract: The objective of this study is to evaluate electrocardiography (ECG)-synchronized pulsatile flow under varying heart rates and different atrial and ventricular arrhythmias in a simulated extracorporeal life support (ECLS) system. The ECLS circuit consisted of an i-cor diag- onal pump and console, an iLA membrane ventilator, and an 18 Fr arterial cannula. The circuit was primed with lactat- ed Ringer’s solution and packed red blood cells (hematocrit 35%). An ECG simulator was used to trigger pulsatile flow and to generate selected cardiac rhythms. All trials were conducted at a flow rate of 2.5 L/min at room temperature for normal sinus rhythm at 45–180 bpm under non-pulsatile and pulsatile modes. Various atrial and ventricular arrhyth- mias were also tested. Real-time pressure and flow data were recorded using a custom-based data acquisition system. The energy equivalent pressure (EEP) generated by pulsa- tile flow was always higher than the mean pressure. No surplus hemodynamic energy (SHE) was recorded under non-pulsatile mode. Under pulsatile mode, SHE levels increased with increasing heart rates (45–120 bpm). SHE levels under a 1:2 assist ratio were higher than the 1:1 and 1:3 assist ratios with a heart rate of 180 bpm. A similar trend was recorded for total hemodynamic energy levels. There was no statistical difference between the two perfusion modes with regards to pressure drops across the ECLS cir- cuit. The main resistance and energy loss came from the arterial cannula. The i-cor console successfully tracked elec- trocardiographic signals of 12 atrial and ventricular arrhyth- mias. Our results demonstrated that the i-cor pulsatile ECLS system can be synchronized with a normal heart rate or with various atrial/ventricular arrhythmias. Further in vivo studies are warranted to confirm our findings. Key Words: Extracorporeal life support—Pulsatile flow—Car- diac arrhythmia—Diagonal pump—Adult. Extracorporeal life support (ECLS) has become a life-saving procedure as a temporary treatment for patients with cardiac and/or pulmonary failure, and it saves thousands of lives worldwide each year (1). Current ECLS systems mostly provide only continu- ous flow when using rotary pumps or ripple flow when using roller pumps. This non-pulsatile blood flow mixes with the weak pulsatile flow of the patient’s native heart during ECLS, thus further weakening circulatory pulsatility, especially in the early stages of cardiac support. Although the non- pulsatile flow can unload left ventricular loading and maintain systemic perfusion, it will increase the left ventricular afterload and may also lead to aortic insufficiency (2,3). The design of pulsatile ECLS, however, accounts for this phenomenon. If the pul- satile peak flow starts at the onset of diastole, there- by increasing diastolic pressure like an intra-aortic balloon pump (IABP), and maintains a low flow rate before systole, thus reducing LV afterload, it must offer a clinical benefit in patients undergoing ECLS. Our previous studies demonstrated that the Medos Deltastream DP3 diagonal pump can generate physiological-like pulsatile flow, deliver more hemo- dynamic energy to the pseudo-patient and create less systemic inflammation and hemolysis compared doi: 10.1111/aor.12904 Received September 2016; revised September 2016. Address correspondence and reprint requests to: Akif € Undar, PhD, Professor of Pediatrics, Surgery, and Bioengineering, Penn State Hershey College of Medicine, Department of Pediatrics – H085, 500 University Drive, P.O. Box 850, Hershey, PA 17033- 0850, USA. E-mail: aundar@psu.edu Presented in part at the 12th International Conference on Pediatric Mechanical Circulatory Support Systems & Pediatric Cardiopulmonary Perfusion held May 18-21, 2016 in New York, NY, USA. Artificial Organs 2017, 41(1):55–65 Copyright V C 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.