DDD pacing and interatrial conduction block: Importance of optimal AV interval setting

The case of a 83-year-old patient undergoing DDD pacemaker implantation for sick sinus syndrome with postimplant detection of advanced interatrial con duction block is described. At nominal AV interval programming values (175 ms), absence of P wave following an atrial spike was observed, and the pres ence of an interatrial conduction disturbance was demonstrated by a Doppler transmitral flow pattern analysis and transesophageal ECG recording. AV in terval lengthening up to 300 ms resulted in proper timing of atrial and ven tricular contractions. Awaiting for conclusive data about biatrial pacing, interatrial conduction blocks can be managed in some cases by proper progra mming of conventional DDD systems.