NPPB and Arrhythmia: We designated cluster 2 as the shock and cardiac cluster because patients in this cluster had the highest prevalence of shock (as indicated in a clinical note or receipt of vasopressors; 69.0%) and reported cardiac involvement (94.4%), comprising shock, elevated troponin level, elevated B-type natriuretic peptide (BNP) level, abnormal echocardiographic results, or arrhythmia (Figure 1; eTable 2 in Supplement 1).