Impact of Allometric Pacing Rate on Ventricular Diastolic Function and Cerebral Blood Flow in Hypertensive Patients With Sinus Node Dysfunction

Impact of Allometric Pacing Rate on Ventricular Diastolic Function and Cerebral Blood Flow in Hypertensive Patients With Sinus Node Dysfunction

The study is a prospective, randomized controlled study in hypertensive patients with a bradycardia indications for pacing therapy and a plan to receive dual-chamber pacemaker. Enrolled patients will be randomized 1:1 into the control group and the allometric-pace group. In the control group, the pacing lower rate will be set to the nominal 60 bpm post a dual-chamber pacemaker implantation as frequently used in clinical practice, while in the allometric-pace group, the pacing rate will be programmed at 75 bpm based on the estimation for Chinese population with a height of 165-170 cm (also called personalized lower rate) or based on the symptom-relief per clinical assessment by the study physicians. Each patient will undergo baseline assessments and 3-month follow-up visits. At the enrollment and office visits, each patient will undergo arterial blood pressure measurement, cardiac functional assessment and cerebral blood flow measurement. At the end of the study, the study physician will adjust pacing lower rate based on patients' conditions and clinical assessments. After the completion of the study, all patients will have regular device follow-up visit, usually 6-month interval or annually.

Each patient will receive the following major assessments: device performance and pacing percentages, ventricular diastolic function by doppler and echocardiography of LVEF, LVEDV, LVESV, stroke volume, cardiac output, arterial blood pressure measurements, cerebral blood flow by MRI or Echo (which one will be determined later by the study PIs), and Mini-Mental State Examination (MMSE).

Inclusion Criteria:

• ≥65 years of age
• Planned implantation of a dual chamber pacemaker with physiological pacing
• Resting sinus heart rate ≤60 bpm, or average 24 hour Holter heart rate ≤60 bpm
• Documented history of hypertension or office systolic blood pressure ≥130 mmHg

Exclusion Criteria:

• Diagnosis of secondary hypertension
• Diagnosis of or possible concomitant heart failure, with ejection fraction ≤50%
• Paroxysmal, persistent, or permanent atrial fibrillation
• Status post CABG or PCI
• Structural heart disease
• Risk of ventricular tachyarrhythmia
• Severe hepatic or renal dysfunction
• Active acute infection
• Inability to sign informed consent
• Pregnancy or planned pregnancy during the study period
• Enrollment in other clinical studies that may affect the objectives of this study