<p>Cardiovascular diseases (CVD) are leading causes of premature mortality, disability, and reduced quality of life worldwide. While extensive literature has addressed cardiovascular risk and treatment, the role of noninvasive interventions in rehabilitation and secondary prevention remains less well defined. Among these, heart rate variability biofeedback (HRVBF) and cardioprotective dietary approaches have shown preventive benefits, yet their effectiveness in patients with established CVD or those undergoing cardiac rehabilitation is not fully established. This review systematically evaluates the evidence for HRVBF and heart-healthy dietary patterns in relapse prevention and rehabilitation, with particular attention to hospital-based contexts. Following PRISMA guidelines, systematic searches were conducted in Scopus and PubMed. Results suggest that HRVBF may enhance autonomic regulation, alleviate psychological distress, and shorten hospital stays. Dietary interventions, particularly those emphasizing omega-3 polyunsaturated fatty acids and Mediterranean-style patterns, demonstrate potential to reduce inflammation and modulate cardiovascular risk markers. Nevertheless, evidence supporting their integration into postoperative rehabilitation or treatment of established CVD remains limited. Heterogeneity in study designs and lack of standardization further constrain generalizability. Overall, the findings underscore the promise of early, noninvasive, and integrative rehabilitation strategies, highlighting the need for structured protocols in clinical settings, particularly during the immediate postoperative phase or after acute cardiac events.</p> Graphical Abstract <p></p>