Background: Acute heart failure and chronic obstructive pulmonary disease (COPD) exacerbation are common, and are sometimes difficult to differentiate in the emergency department (ED). Objectives: To determine the clinical impact of Point-of-Care Ultrasonography (POCUS) in ED patients with suspected acute heart failure or COPD. Methods: We conducted a prospective health records review with 1:3 matching, and analyzed time to events using time-dependent Cox regression analyses, classification performance, and adverse events. Results: There were 81 patients with lung POCUS and 243 matched patients. No differences were found in ED length of stay or length of care, nor adverse events. Significance was found for time to treatment (P=0.03). Lung POCUS had high sensitivity (92.5%) and specificity (85.7%) for identifying acute heart failure. Conclusions: Lung POCUS could result in faster treatments for patients with suspected acute heart failure and COPD, and has high accuracy in identifying acute heart failure.