Synergistic impact of nondipper heart rate and blood pressure on left ventricular hypertrophy in essential hypertension

BACKGROUND: Left ventricular hypertrophy (LVH) is a serious complication of hypertension. However, the association between the nondipper heart rate (NDHR) and the risk of LVH remains unclear. METHODS: A cross-sectional analysis was conducted involving 991 patients with essential hypertension. NDHR was defined as a <10% reduction in nocturnal heart rate assessed by 24-h ambulatory blood pressure monitoring. Propensity score matching (PSM) was used to balance baseline characteristics. The independent association was assessed using multivariable logistic regression, and interactions were evaluated on multiplicative and additive scales. RESULTS: = 0.024). A significant synergistic interaction was observed between NDHR and nondipper blood pressure, with the dual nondipper phenotype conferring the highest odds of LVH (OR = 2.52 [95%CI: 1.68-3.78]). Additive interaction measures confirmed biological synergy (RERI = 0.98; AP, 0.39). A nomogram incorporating NDHR demonstrated acceptable discrimination for LVH (AUC = 0.66 [95%CI: 0.61-0.71]) and provided superior net benefit across a wide threshold probability range (20%-80%). Subgroup analyses indicated stronger associations in younger patients and those not using ACEI/ARBs. CONCLUSION: NDHR is an independent risk factor for LVH and exhibits significant synergy with NDBP. Assessment of nocturnal heart rate decline, despite its behavioral confounders, may enhance cardiovascular risk stratification in hypertension.