Obesity-induced heart failure (HF) in young people is a serious problem. The treatments for HF have developed in recent years. The following four basic HF drugs have been widely recognized as the \"Fantastic Four\": beta-adrenergic blocking agents, mineralocorticoid receptor antagonists (MRA), sodium glucose transporter 2 inhibitors (SGLT2 inhibitors), and angiotensin receptor neprilysin inhibitors (ARNI). However, the interaction between the heart and blood vessels has not received much attention. The cardio-ankle vascular index (CAVI) is an arterial stiffness index that is unaffected by blood pressure at the time of measurement. A 34-year-old obese man was admitted with dyspnea and edema. His cardiac function was severely impaired, and CAVI was increased. After administration of multidisciplinary HF treatment centered on the \"Fantastic Four\", his cardiac function and CAVI improved dramatically in a short time period. This case suggests the importance of improvement both cardiac and vascular function for the treatment of HF.