We assessed the feasibility of achieving acute, sustained blood pressure reductions through the use of cardiac pacing algorithms delivered via standard dual-chamber pacing based on introducing short atrio-ventricular (AV) delays (SAVD). Eighteen hypertensive subjects (57.3 +/- 9.8 years old; 10 male and 8 female) with average initial systolic and diastolic blood pressures of 151.2 +/- 17.6/92.2 +/- 12.7 mmHg already scheduled to undergo an invasive electrophysiology procedure were included in this study. Pacing sequences were applied for approximately 1-minute intervals with AV delays of 80, 40, 20 and 2 ms, while making high fidelity blood pressure measurements. Average reductions of 19.6 +/- 7.7 mmHg in systolic pressure and 4.3 +/- 3.8 mmHg in diastolic pressure (P < .001 each) were demonstrated with 2 ms AV delay pacing. Initial SBP reductions were followed by rebound effects which diminished the SBP reducing effects of SAVD pacing, likely due to baroceptor activation causing increased peripheral resistance. This effect was eliminated by intermittent introduction of longer AV delay pacing which modulated the baroreflexes. These findings provide the rationale and evidence underlying recent data showing significant and long-term blood pressure reductions in response to this cardiac neuromodulation therapy in hypertensive patients despite medical therapy
Tags: HTN, hypertension