Objective: To determine the right ventricular (RV) systolic function echocardiographic parameter best associated with native stroke volume (SV) by thermodilution via pulmonary artery catheter (PAC) in patients admitted to intensive care with ST-elevation myocardial infarction (STEMI) complicated by cardiogenic shock (CS).Design, Setting, and Participants: Observational cohort study of 43 prospectively identified patients admitted to a tertiary cardiac intensive care unit in London, UK.Interventions: Simultaneous collection of comprehensive transthoracic echocardiographic, clinical, and PAC-derived hemodynamic data. Seven RV systolic function parameters were correlated with the PAC-derived SV.Measurements and Main Results: The median age was 61 [52, 67], and 36 patients (84%) were male. The median PAC-derived SV and LVEF were 57 ml [39, 70] and 31% [22, 35], respectively. The RV outflow tract velocity time integral (RVOT VTI) and tricuspid plane systolic excursion (TAPSE) correlated significantly with the PAC-derived SV (r = 0.42, p = 0.007, r = 0.37, p = 0.02, respectively). The RVOT VTI was independently associated with and predicted low PAC-derived SV (OR = 1.3, p = 0.03) with a good area under the curve (AUC = 0.71, p = 0.02). The RVOT VTI < 12.7 cm predicted low PAC-derived SV with a sensitivity of 66% and specificity of 72%.Conclusion: RVOT VTI is the echocardiographic RV systolic function parameter that best correlates with PAC-derived native SV in patients with STEMI complicated by CS. This parameter can help guide the hemodynamic management of this cohort.