The Influence of Heart Rate on Peripheral Vascular Function Among Pacemaker Patients.

The finger photoplethysmography fitness index (PPGF), a marker of peripheral vascular function, has been linked to heart rate (HR) variability. However, the influence of acute HR changes on resting PPGF, a purported indicator of local blood flow, remains unclear. This study aimed to determine the influence of acute HR changes on resting PPGF. A total of 22 pacemaker recipients (mean age: 52.27 ± 10.43 years) underwent a controlled study. Baseline assessments included demographics, blood pressure (BP), blood analysis, PPGF, and vascular functions. HR was progressively increased from 70 bpm to 90 bpm in 10 bpm increments with 20 min resting periods at baseline and between pacing intervals. HR, PPGF, and BP were recorded at each pacing level. Systolic and diastolic BP increased with rising HR. Conversely, PPGF remained stable across different HR levels (70 bpm: 51.02 ± 11.52%, 80 bpm: 51.15 ± 11.82%, 90 bpm: 49.73 ± 11.55%; p > 0.05), suggesting that resting PPGF is independent of acute HR fluctuations. Our findings demonstrate that PPGF accurately reflects local blood flow, unaffected by short-term HR variations. This study supports the use of PPGF as a reliable marker for vascular health and age assessment, even in individuals with fluctuating HR, such as older adults with multiple comorbidities. Further research is warranted to establish the applicability of PPGF in younger, healthier populations.