An ablation catheter comprises a catheter body extending longitudinally between a proximal end and a distal end along a longitudinal axis； and an ablation element assembly comprising ablation elements connected to the catheter body, each ablation element to be energized to produce an ablation zone. The ablation elements are distributed in a staggered configuration such that the ablation zones of the ablation elements span one or more open arc segments around the longitudinal axis, but the ablation zones of all ablation elements projected longitudinally onto any lateral plane which is perpendicular to the longitudinal axis span a substantially closed loop around the longitudinal axis. Since the ablation zones do not form a closed loop, the risk of renal artery/vein stenosis is reduced or eliminated. Since the ablation zones of all ablation elements projected longitudinally onto any lateral plane span a substantially closed loop, substantially complete renal denervation is achieved.
