Pulse wave velocity (PWV) is a new technique and frequently used today to determine the elastic distensibility of great arteries. Increased arterial stiffness and PWV have been proposed as possible mechanisms in the initiation and/or progression and/or complications of atherosclerosis and cardiovascular disease. We evaluated the acute effect of two frequently used pacing modes (DDD vs. VVI) on arterial distensibility using PWV. Methods: Seventeen patients ( age, 56 +/- 14 years) implanted with DDD pacemakers were included in the study. All patients were pacemaker dependent and continuously paced at the programmed rate. PWV was measured first in DDD mode, and then the mode was switched to VVI, and PWV was measured again at the same programmed heart rate as in the DDD mode. Results: Although systolic blood pressure significantly decreased from 129 +/- 18 to 119 +/- 16 mm Hg (p = 0.001) after switching the mode from DDD to VVI, diastolic blood pressure (81 +/- 12 vs. 80 +/- 13 mm Hg; p = 0.38) did not change. In addition, PWV significantly increased from 11 +/- 2.46 m/s in DDD mode to 11.29 +/- 2.43 m/s (p = 0.01) after having been programmed to VVI mode. Conclusions: Our results suggest that VVI pacing increases PWV, and therefore decreases arterial distensibility, and thus may contribute to the development and progression of atherosclerosis. Copyright (C) 2004 S. Karger AG, Basel.