Heart failure (HF) and atrial fibrillation (AF) are among the most prevalent cardiovascular diseases, often coexisting and sharing common pathophysiological pathways such as systemic inflammation, oxidative stress, mitochondrial dysfunction, and endothelial impairment. Despite substantial progress in pharmacological treatment, including renin-angiotensin-aldosterone system (RAAS) inhibitors, beta-blockers, sodium-glucose cotransporter 2 (SGLT2) inhibitors, mineralocorticoid receptor antagonists (MRAs), diuretics, and antiarrhythmic drugs, many patients continue to experience residual symptoms and drug-related adverse effects. Nutraceuticals have emerged as potential adjuncts to conventional therapy due to their ability to modulate key biological processes involved in HF and AF. Polyphenols from Olea europaea, Hibiscus sabdariffa, Camellia sinensis, and Vitis vinifera (resveratrol) exhibit antioxidant, anti-inflammatory, and vasoprotective effects. Omega-3 fatty acids and astaxanthin contribute to inflammation control and redox balance, while Orthosiphon stamineus and Taraxacum officinale show mild diuretic activity. Moreover, anthocyanins, ursolic acid, and Rhodiola crenulata may exert antifibrotic and antiarrhythmic properties. This review provides a mechanistic comparison between pharmacological agents and nutraceuticals with overlapping mechanisms of action, highlighting their potential role in integrative cardiovascular care. While nutraceuticals are not substitutes for established therapies, emerging evidence supports their complementary use in improving treatment response, reducing side effects, and enhancing patient outcomes. Future research should focus on large-scale trials, improved bioavailability, standardized formulations, and the development of personalized therapeutic strategies. Challenges related to dosage consistency, clinical validation, and regulatory oversight are also addressed to guide innovation in integrative cardiology.
