The RVPA Coupling in Chronic RV Failure

CardioNerd (Daniel Ambinder) and series co-chairs Mark Belkin (AHFT Fellow, University of Chicago) and Karan Desai (Cardiologist, Johns Hopkins), join fellow lead, Dr. Pablo Sanchez (FIT, Stanford) for a discussion with Dr. Ryan Tedford (Professor of Medicine at the Medical University of South Carolina) about Right Ventricular (RV) predominant cardiogenic shock. In this episode we explore risk factors, pathophysiology, hemodynamics, and treatment strategies in this common and complex problem. We dissect three cases that epitomize the range of diagnostic dilemmas and management decisions in RV predominant shock, as Dr. Tedford expertly weaves us through the pathophysiology and decision-making involved in managing the “people’s ventricle.” Audio editing by Dr. Gurleen Kaur (Director of the CardioNerds internship program, CardioNerds academy fellow, and IM resident at Brigham and Women’s Hospital). The CardioNerds Cardiac Critical Care Series is a multi-institutional collaboration made possible by contributions of stellar fellow leads and expert faculty from several programs, led by series co-chairs, Dr. Mark Belkin, Dr. Eunice Dugan, Dr. Karan Desai, and Dr. Yoav Karpenshif. Pearls • Notes • References • Production Team CardioNerds Cardiac Critical Care PageCardioNerds Episode PageCardioNerds AcademyCardionerds Healy Honor Roll CardioNerds Journal ClubSubscribe to The Heartbeat Newsletter!Check out CardioNerds SWAG!Become a CardioNerds Patron! Pearls and Quotes - RV Predominant Cardiogenic Shock The degree of RV dysfunction and failure are modulated by stretching its capacity to tolerate insults from deranged afterload, preload, and contractility.Afterload insults are MUCH LESS tolerated than other insults and broadly comprise the most common pathophysiologic cause of both acute and chronic RV failure.RV and left ventricular (LV) function are anatomically and physiologically connected.  Progressive derangements in RV function can lead to the deadly “RV spiral,” in which poor RV function causes lower LV preload, leading to hypotension, and thus worsening RV perfusion and function.In RV failure/shock, some basic tenets including treating reversible causes, optimizing preload and afterload, and using inotropes and/or temporary MCS for as limited time as possible.Many acute RV failure patients can recover, but multiorgan injury plays an important role. Therefore, thoughtful and expeditious use of mechanical circulatory support is important. Show notes - RV Predominant Cardiogenic Shock Notes drafted by Dr. Pablo Sanchez. What is the basic difference between RV dysfunction and failure?Dysfunction: Abnormalities in systolic/diastolic function of the RV, but not necessarily to the point of leading to end-organ perfusion defects. RV dysfunction leads to poor outcomes regardless of mechanism.1Failure: Clinical syndrome of inability of RV to maintain adequate output despite adequate preload. 1 How is the RV different from the LV and what impact does it have on pathophysiology and hemodynamics?The LV and RV originate from different embryologic “heart fields.”1,2The RV wall is thinner and more compliant and has only two layers (instead of 3 like the LV).3 Furthermore, unlike the LV which has a significant proportion of endocardial and epicardial transverse myocardial fibers, the RV myocardial fibers are aligned in a longitudinal plane for the most part. Thus, a more significant proportion of RV systolic contraction is longitudinal – base of the ventricle moving towards the apex.The RV is crescent-shaped and has a large surface-to-volume ratio meaning smaller inward motion ejects the same stroke volume. 1Hemodynamically, the RV takes blood from a low-pressure venous system and gives it to a distensible system with low impedance (the normal pulmonary circuit at baseline typically has a resistance one-tenth of the systemic resistance). Therefore, volume loads (preload) are much better handled...