Background: About 80% of cardiovascular diseases (including heart failure [HF]) occur in low-income and developing countries. However, most clinical trials are conducted in developed countries. Hypothesis: The American Registry of Ambulatory or Acutely Decompensated Heart Failure (AMERICCAASS) aims to describe the sociodemographic characteristics of HF, comorbidities, clinical presentation, and pharmacological management of patients with ambulatory or acutely decompensated HF in America. Methodology: Descriptive, observational, prospective, and multicenter registry, which includes patients >18 years with HF in an outpatient or hospital setting. Collected information is stored in the REDCap electronic platform. Quantitative variables are defined according to the normality of the variable using the Shapiro-Wilk test. Results: This analysis includes data from the first 1000 patients recruited. 63.5% were men, the median age of 66 years (interquartile range 56.7-75.4), and 77.6% of the patients were older than 55 years old. The percentage of use of the four pharmacological pillars at the time of recruitment was 70.7% for beta-blockers (BB), 77.4% for angiotensin-converting enzyme inhibitor (ACEI)/angiotensin II receptor blocker (ARB II)/angiotensin receptor-neprilysin inhibitor (ARNI), 56.8% for mineralocorticoid receptor antagonists (MRA), and 30.7% for sodium-glucose cotransporter type-2 inhibitors (SGLT2i). The main cause of decompensation in hospitalized patients was HF progression (64.4%), and the predominant hemodynamic profile was wet-warm (68.3%). Conclusions: AMERICCAASS is the first continental registry to include hospitalized or outpatient patients with HF. Regarding optimal medical therapy, approximately a quarter of the patients still need to receive BB and ACEI/ARB/ARNI, less than half do not receive MRA, and more than two-thirds do not receive SGLT2i.