Prognostic Value of Non-Dipping Nocturnal Heart Rate for Ventricular Arrhythmias in Isolated Hypertension

Abstract

This study examined the association between a blunted nocturnal heart rate decline and ventricular arrhythmias, echocardiographic findings, and clinical characteristics in patients with isolated hypertension (defined as hypertension in the absence of other systemic comorbidities). A total of 229 adults who underwent transthoracic echocardiography and 24-hour Holter monitoring were retrospectively evaluated. Patients were classified as dippers (≥10% nocturnal heart rate reduction; n = 170) or non-dippers (<10% reduction; n = 59), and were also compared according to Lown classes 0 versus 1-4. Baseline demographics, laboratory parameters, and antihypertensive treatments were similar between groups. Non-dippers demonstrated greater interventricular septal and posterior wall thickness, higher left ventricular mass and mass index, and a higher prevalence of left ventricular hypertrophy and concentric hypertrophy (P < .05 for all). They also exhibited more frequent ventricular and atrial ectopy. Patients in Lown classes 1-4 had higher systolic blood pressure, more pronounced left ventricular remodeling, and a greater arrhythmic burden. In multivariable analysis, concentric hypertrophy (Odds Ratio [OR]: 2.682; P = .034) and non-dipping nocturnal heart rate (OR: 9.254; P = .001) were independent predictors of arrhythmias. These findings suggest that non-dipping nocturnal heart rate (reflecting impaired parasympathetic activity and relative sympathetic predominance) is associated with adverse cardiac remodeling and increased arrhythmia risk in isolated hypertension.