Rate control in permanent atrial fibrillation based on beat-to-beat blood pressure monitoring using the volume clamp method

Aim. To assess how adjustment of rate control therapy in permanent atrial fibrillation (AF) affects beat-to-beat hemodynamic metrics derived from continuous beatto-beat blood pressure monitoring. Material and methods. The study included 32 patients with permanent non-valvular AF (69,5±12,0 years; 20 men). Two 15-minute ECG recordings with synchronous beat-to-beat blood pressure monitoring were obtained before and 14-17 days after initiation or adjustment of rate control therapy. Mean arterial pressure (MAP), MAP variability (average real variability (ARV), root mean square of successive differences (RMSSD)), the proportion of hemodynamically ineffective beats (HIB; at three relative pulse-pressure thresholds), heart rate (HR), RR variability indices (nRMSSD, CVRR, pNN10%), and the burden of short RR (proportion of RR intervals below an individual RRx threshold) were calculated. Results. HR decreased from 106,6±12,1 to 85,4±10,5 bpm (p<0,001). The proportion of HIB decreased at all thresholds (mild 26,5±8,4→ 13,5±8,0%, moderate 15,2±8,8 → 6,0±6,8%, severe 6,8±5,4→ 2,4±3,6%; p for all <0,001). MAP remained stable (94,3±11,6 → 93,3±13,7 mm Hg; p=0,67), whereas MAP variability decreased (ARV and RMSSD: p for both <0,001). RR variability parameters increased (nRMSSD, CVRR, pNN10%; all p<0,001), and the burden of short RR fell from 37,5±12,5 to 12,7±9,7% (p<0,001). With β-blocker monotherapy, reductions in mild HIB and short-RR burden were more pronounced, whereas adding digoxin was associated with a greater increase in pNN10%. Despite consistent group-level trends, marked inter-individual differences in response were observed. Conclusion. Adjustment of rate control therapy in permanent AF is associated with fewer HIBs, lower MAP variability and a reduced burden of short RR intervals without a decrease in mean MAP, thereby improving beat-to-beat hemodynamic metrics while preserving systemic blood pressure. The inter-individual heterogeneity of these effects at similar HRs supports personalized rate control strategies targeting not only average HR but also beat-to-beat hemodynamic parameters and warrants confirmation in larger prospective studies.