Techniques are described for use with an implantable cardiac stimulation device for performing paired/coupled pacing either alone or in conjunction with dynamic overdrive/underdrive pacing. In one technique, dynamic overdrive/underdrive pacing is delivered to the ventricles using paired pulses during an episode of atrial fibrillation. The use of paired pulses during dynamic ventricular overdrive/underdrive pacing helps lower and stabilize the ventricular rate to thereby reduce the risk of a ventricular arrhythmia. In another technique, the inter-pulse interval between paired pulses is optimized to lengthen the resulting refractory period to improve hemodynamics. Preferably, the optimized inter-pulse interval is used when applying dynamic ventricular overdrive/underdrive pacing with paired pulses so that the benefits of both techniques are obtained. The optimization technique is also applicable to setting the coupling interval for use with coupled pacing.
