Heart rate reduction decreases central blood pressure in sick sinus syndrome patients with a permanent cardiac pacemaker

Increased resting heart rate (HR) contributes to higher cardiovascular mortality and morbidity in the healthy as well as in people with cardiovascular diseases, possibly due to elevated blood pressure (BP) among other mechanisms. Data on the relationship between HR and central (aortic) BP remains controversial, however, and concerning β-blockers, it has been proposed that pharmacological HR lowering is associated with augmentation of central BP. We aimed to study the role of pharmacologically unaffected HR on central BP indices in sick sinus syndrome patients with a permanent cardiac pacemaker in the HR range from 40 to 90 bpm. We included 27 subjects (mean age 65.8 ± 9.5 years, 12 men) with a dual-chamber pacemaker implanted due to sick sinus syndrome. We determined central hemodynamic indices noninvasively during an atrial pacing mode at low (40 bpm), middle (60 bpm), and high (90 bpm) HR levels with an oscillometric cuff-based device (Sphygmocor XCEL). There was no difference in central systolic BP at the middle versus the high HR level (mean 121.2 ± 13.0 and 121.2 ± 12.1 mmHg, respectively, P = 0.9), but at the low HR level, it was significantly lower than at the middle HR level (mean 117.2 ± 13.1 and 121.2 ± 13.0 mmHg, P < 0.01). Our acute study provides evidence to suggest that at a HR of <60 bpm, sick sinus syndrome patients may have a lower central BP than at a higher HR, despite the proposed augmenting effects of low HR on central BP.