Advances in pacing therapy for bradycardia.

Advances have been made rapidly in the field of cardiac pacing. The most significant technologic advance is that of pacemakers capable of rate-adaptive pacing. Multiple types of sensors are now used for rate-adaptive pacing; some are commercially available and many are undergoing clinical investigation. In the near future, clinical investigation will begin on pacemakers that incorporate dual simultaneous sensors for rate-adaptive pacing. Significant improvement has been made in electrode design. Electrodes with low thresholds allow improved battery longevity. Steroid-eluting leads have proven reliable and capable of avoiding the early threshold rise seen with other electrodes. Standardization of pacemaker connector dimensions is now under way. The International Standards Organization has established the guidelines for connector standardization, and the guidelines have been adopted by the major manufacturers. The ultimate "smart" pacemaker would be capable of autoprogramming most or all of its programmable features. Many autoprogramming features have already been incorporated, and several others such as automatic programming of output and sensitivity are under investigation.