A wide range of comorbidities play a pivotal role in worsening outcomes and increasing mortality risk in patients with heart failure (HF). Among them, renal dysfunction has been recognized as a highly prevalent prognostic variable, with a strong impact on prognosis, length of hospital stay and need for intensive care. In this context, recent evidence has pointed out the relevance of both systemic hypoperfusion and venous congestion on the imbalance of renal function as well as on the conditioning the pathophysiological crosstalk between heart and kidneys through a wide range of haemodynamic and biochemical pathways. This narrative review aims to investigate the intricate interplay between impaired systemic perfusion and venous congestion in cardiorenal syndrome, as well as their haemodynamic and biochemical implications for renal damage in HF.