Heart failure (HF) guidelines recommend treating all patients with HF and reduced ejection fraction (HFrEF) with quadruple therapy, although they do not establish how to start it. This study aimed to evaluate the implementation of these recommendations, analyzing the efficacy and safety of the different therapeutic schedules. Prospective, observational, and multicenter registry that evaluated the treatment initiated in patients with newly diagnosed HFrEF and its evolution at 3 months. Clinical and analytical data were collected, as well as adverse reactions and events during follow-up. Five hundred and thirty-three patients were included, selecting four hundred and ninety-seven, aged 65.5 ± 12.9 years (72% male). The most frequent etiologies were ischemic (25.5%) and idiopathic (21.1%), with a left ventricular ejection fraction of 28.7 ± 7.4%. Quadruple therapy was started in 314 (63.2%) patients, triple in 120 (24.1%), and double in 63 (12.7%). Follow-up was 112 days IQI 91; 154, with 10 (2%) patients dying. At 3 months, 78.5% had quadruple therapy (p < 0.001). There were no differences in achieving maximum doses or reducing or withdrawing drugs (< 6%) depending on the starting scheme. Twenty-seven (5.7%) patients had any emergency room visits or admission for HF, less frequent in those with quadruple therapy (p = 0.02). It is possible to achieve quadruple therapy in patients with newly diagnosed HFrEF early. This strategy makes it possible to reduce admissions and visits to the emergency room for HF without associating a more significant reduction or withdrawal of drugs or significant difficulty in achieving the target doses.