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 conduction block is described. At nominal AV interval programming values (175 ms), absence of P wave following an atrial spike was observed, and the presence of an interatrial conduction disturbance was demonstrated by a Doppler transmitral flow pattern analysis and transesophageal ECG recording. AV interval lengthening up to 300 ms resulted in proper timing of atrial and ventricular contractions. Awaiting for conclusive data about biatrial pacing, interatrial conduction blocks can be managed in some cases by proper programming of conventional DDD systems.

[Single-lead VDD pacing with sensing dipole in the coronary sinus: a case of implantation through persistent left superior vena cava]. / Stimolazione VDD monocatetere con sensing in seno coronarico: un caso di impianto attraverso vena cava superiore sinistra persistente.

We report the case of a VDD single-lead pacemaker implantation through a persistent left superior vena cava in a 48-year-old male patient with recurrent episodes of syncope due to paroxysmal atrioventricular block. VDD lead insertion through the anomalous venous structure led to positioning of the floating sensing dipole into the coronary sinus, in a very large and stable sensed atrial signal due to the close anatomic relationship between the coronary sinus and the left atrium. Shortness of the sensed atrioventricular interval allowed VDD stimulation to occur only in the case of paroxysmal atrioventricular block.