When the model was further extended by the potential confounders AF, diabetes, arterial hypertension, NT-proBNP level, and eGFR, a trended positive correlation between HFpEF and NaV1.5 phosphorylation persisted without reaching statistical significance (B [95% CI]: 0.559 [−0.137; 1.254], R2 = 0.368, P = 0.107, Model II, Supplementary material online, Table S1). Here, NPPB is linked to atrial fibrillation.