The Potential of Nocturnal Heart Rate as a Predictor of Target Organ Damage in Individuals Diagnosed with Hypertension

Abstract

Background: Elevated nocturnal heart rate (NHR) has been linked to an increased risk of cardiovascular events and mortality in hypertensive patients. However, the ability of NHR to predict the occurrence and progression of target organ damage (TOD) in these patients requires further investigation. This study aims to evaluate the predictive value of NHR in forecasting the presence and severity of TOD in hypertensive patients, using a combination of clinical and laboratory parameters. Methods: A total of 145 hypertensive patients were monitored for blood pressure and nocturnal heart rate. Patients were categorized into two groups based on the presence or absence of TOD and their NHR. The left ventricular mass index (LVMI), glomerular filtration rate (GFR), carotid intima media index (CTIM), and left ventricular ejection fraction (LVEF) were measured, and multiple linear regression was used to determine the predictive value of NHR on these indices. Results: The group with TOD had significantly higher NHR than the group without TOD. LVMI, GFR, CTIM, and LVEF varied significantly among the three subgroups, with the NHR3 group showing marked differences compared to the NHR2 and NHR1 groups (p < 0.01 or p < 0.05). Excessively rapid NHR had diverse impacts on all categories of target organs, particularly on LVMI and CTIM. Conclusion: Augmentation of nocturnal heart rate causes heightened harm to the target organs, with the most significant impact observed in LVMI and CTIM. No significant difference in the severity of TOD was observed between patients with an NHR of less than 70 bpm and those with an NHR between 70 and 80 bpm. However, an NHR above 80 bpm resulted in more severe TOD. These findings suggest that monitoring NHR in hypertensive patients may help prevent and manage TOD.