Right Ventricular Failure - Diagnosis and Management
Right Ventricle Physiology
• RV has thinner myocardium compared to LV->↑ compliance compared to LV, so it does not adapt well to acute increases in pressure
• RV and LV are interdependent->failure of RV leads to failure of LV through several mechanisms: (a) decreased LV preload (because RV output = LV preload; (b) septal bowing into LV, causing diastolic impairment (“Bernheim effect”)
Acute Changes in RV Hemodynamics
• ↑ RV afterload (e.g., PE), ↑ RV preload (e.g., L->R shunting through ASD/VSD), or ↓ RV contractility (e.g., MI) all lead to increased RV wall stress and resultant ischemia
• RV CO subsequently ↓ and RV dilates, precipitating RV “death spiral”
Clinical Features and Workup
• Exam: Elevated JVP, peripheral edema, RV heave, pulsatile liver. Less common: Split S2, new tricuspid regurgitation (loudest: RLSB)
• Imaging: CXR->hard to evaluate RV 2/2 position, lateral film can help; CT->best for RV size/septum position
• Echocardiography: measure RV size/function to elucidate underlying etiology. RVEF based on displacement of base towards apex (tricuspid annular plane systolic excursion [TAPSE], nl 2.4-2.7cm).
• RHC: gold standard for measurement of ventricular filling pressures, CO, PA pressures
• Labs: NT-proBNP and troponin are not specific but can indicate RV failure if no L-sided disease.
• Identify and treat triggers: infection, anemia, arrhythmia, PE, MI, hypoxia
• Preload: Clinical assessment of optimal preload is challenging. Both hypo- and hypervolemia may ↓ CO.
o Acute: consider volume loading in pts with acute RVMI or PE in absence of marked CVP elevation (“preload-dependent”)
o Subacute/chronic: consider diuresis to reduce RV filling pressures and improve RV CO
• Afterload - Systemic: if pt hypotensive, start systemic pressors; no clinical data regarding pressor of choice, but often choose or vasopressin or norepinephrine because it affects SVR>>PVR
• Contractility: often use milrinone to enhance pulmonary vasodilation (vasodilates arteries in both systemic and pulmonary circulation)
Intubation and Mechanical Ventilation
Right Ventricular Myocardial Infarction
• EKG: Check R-sided EKG leads in pts with inferior STEMI (10-15% of pts with inf. STEMI have RV involvement)
• Management: pts with RVMI are initially “preload-dependent” and often benefit from fluid bolus; caution w/ TNG (↓ preload) and BB (↓HR)
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