Nocturnal Blood Pressure Dipping and Ventricular Repolarization in Hypertension

Hypertension is a highly prevalent chronic condition and one of the leading causes of cardiovascular disease worldwide. It is associated with structural and electrical remodeling of the heart, including left ventricular hypertrophy, myocardial fibrosis, and impaired ventricular repolarization. These changes predispose patients to arrhythmias and adverse cardiovascular outcomes.

A physiological decline in blood pressure during nighttime, known as nocturnal dipping, represents a normal circadian rhythm and is considered a favorable prognostic sign. However, many hypertensive patients fail to show this nocturnal decline (non-dippers), which may indicate heightened sympathetic activity, impaired recovery during sleep, and increased cardiovascular risk. Identifying the impact of dipping status on cardiac electrical and mechanical function could therefore have important clinical value.

This study is designed as an observational prospective registry enrolling adult patients with essential hypertension. All participants will undergo 24-hour ambulatory blood pressure monitoring to determine dipping pattern, standard 12-lead electrocardiography for analysis of repolarization markers such as QTc, QT dispersion, and Tp-Te interval, and comprehensive transthoracic echocardiography including strain imaging to assess myocardial mechanics. Laboratory tests including electrolytes and renal function will also be performed to exclude confounding factors.

The primary objective is to evaluate the effect of nocturnal blood pressure dipping on ventricular repolarization parameters and echocardiographic findings in hypertensive patients. Secondary objectives include assessing differences between resistant and non-resistant hypertension as well as controlled and uncontrolled hypertension groups. The study is expected to provide novel insights into the prognostic role of dipping status and its association with electrical and functional cardiac abnormalities.

Inclusion criteria

• Adults ≥18 years old
• Diagnosed with essential hypertension
• Completed 24-hour ambulatory blood pressure monitoring (ABPM)
• Availability of good-quality 12-lead ECG
• Availability of good-quality transthoracic echocardiography

Exclusion criteria

• Body mass index (BMI) > 34.9 kg/m²
• Atrial fibrillation or atrial flutter
• Use of QT-prolonging medications
• End-stage renal disease or liver failure
• Bundle branch block or presence of pacemaker
• Prior coronary revascularization (PCI or CABG)
• Significant electrolyte imbalance