Reverse cardiac remodeling after renal denervation: Atrial electrophysiologic and structural changes associated with blood pressure lowering

BACKGROUND Hypertension is the most common modifiable risk factor associated with atrial fibrillation. OBJECTIVE The purpose of this study was to determine the effects of blood pressure (BP) lowering after renal denervation on atrial electrophysiologic and structural remodeling in humans. METHODS Fourteen patients (mean age 64 +/- 9 years, duration of hypertension 16 +/- 11 years, on 5 +/- 2 antihypertensive medications) with treatment-resistant hypertension underwent baseline 24-hour ambulatory BP monitoring, echocardiography, cardiac magnetic resonance imaging, and electrophysiologic study. Electrophysiologic study included measurements of P-wave duration, effective refractory periods, and conduction times. Electroanatomic mapping of the right atrium was completed using CART03 to determine local and regional conduction velocity and tissue voltage. Bilateral renal denervation was performed, and all measurements repeated after 6 months. RESULTS After renal denervation, mean 24-hour BP reduced from 152/84 mm Hg to 141/80 mm Hg at 6-month follow-up (P < .01). Global conduction velocity increased significantly (0.98 7 +/- 0.13 m/s to 1.2 +/- 0.16 m/s at 6 months, P < .01), conduction time shortened (32 +/- 5 ms to 27 +/- 6 ms, P < .01), and complex fractionated activity was reduced (37% +/- 14% to 19% +/- 12%, P = .02). Changes in conduction velocity correlated positively with changes in 24-hour mean systolic BP (R-2 = 0.55, P = .01). There was a significant reduction in Left ventricular mass (139 +/- 37 g to 120 +/- 29 g, P < .01) and diffuse ventricular fibrosis (T-1 partition coefficient 0.39 +/- 0.07 to 0.31 +/- 0.09, P = .01) on cardiac magnetic resonance imaging. CONCLUSION BP reduction after renal denervation is associated with improvements in regional and global atrial conduction and reductions in ventricular mass and fibrosis. Whether changes in electrical and structural remodeling are solely due to BP lowering or are due in part to intrinsic effects of renal denervation remains to be determined.