The Impact of Heart Rate on Central Blood Pressure in Sick Sinus Syndrome Patients With a Permanent Cardiac Pacemaker

Inclusion Criteria: * age 18-75 years; * dual-chamber pacemaker implanted due to sick sinus syndrome at least six months before; sinus rhythm Exclusion Criteria: * average seated office brachial systolic BP ≥160 mmHg and/or diastolic BP ≥ 100 mmHg; atrial pacing \<40%; * ventricular pacing \>25%; * unpaced QRS \>120 ms and/or QTc \>500 ms on 12-lead ECG; * atrioventricular blockage at AAI-mode 90 bpm; resting HR \>60 bpm at AAI-mode 40 bpm; irregular heart rate; * automatic mode switching \>10%; * implantable cardioverter defibrillator or cardiac resynchronisation therapy pacemaker; treatment with digoxin, class Ic or III antiarrhythmic drugs; * history of acute coronary syndrome; * stable angina pectoris; * heart failure with reduced left ventricular ejection fraction; * history of cerebrovascular event; * diabetes mellitus; * chronic kidney disease with eGFR \<30 ml/min/m2; * peripheral artery disease; * clinically relevant heart valve disease; * active cancer; * acute or chronic inflammatory disease; * severe chronic respiratory or liver disease; * pregnancy or breastfeeding * contraindication or intolerance to atenolol, nebivolol, ivabradine or adjuvants