The presence of a larger amount of LV area with late Endo-AT and preserved LV myocardium measured by electromechanical mapping could identify patients who have better acute improvement in systolic performance during LV stimulation.

In patients with SND and paroxysmal AF, right low AS pacing significantly improved global and regional atrial mechanical function and synchronized inter-atrial electromechanical contraction compared with RAA pacing.

The Septal Pacing for Atrial Fibrillation Suppression Evaluation (SAFE) study is a single-blinded, parallel randomized designed multicenter study in pacemaker indicated patients with paroxysmal atrial fibrillation (AF). The objective is to evaluate whether the site of atrial pacing--conventional right atrial appendage versus low atrial septal--with or without atrial overdrive pacing will influence the development of persistent AF. The study will provide a definitive answer to whether a different atrial pacing site or the use of AF suppression pacing or both can give incremental antiarrhythmic benefit when one is implanting a device for a patient with a history of paroxysmal AF.

This study evaluated the performance of a new lead for permanent left ven tricular (LV) pacing via the coronary sinus (CS) in four men and nine women (mean age = 71 ±13 years) with sick sinus syndrome. It consists of a unipolar ventricular lead with a distal portion preshaped in an S curve to provide steerability and stability within the CS. Its efficacy and stability for per manent LV pacing were tested at implant, predischarge, and at 1, 3 and 6 months of follow-up. The lead was successfully implanted in 11/13 patients (85%) within a mean fluoroscopy time of 35 ± 22 minutes. The final positions of the electrodes at the tip of the lead within venous tributaries of the CS were: (1) an terior (n = 2, 18%); (2) posterolateral (n = 5, 45%); and (3) the lateral (n = 4, 36%). Unsuccessful implants were due to unstable lead position (n = 1), or high pacing threshold (n = 1). There was no postprocedural lead dislodgment or significant changes in the R wave amplitude, LV pacing threshold and lead impedance up to 6 months of follow-up. In summary, this initial experience suggests that this new lead offers safe and reliable permanent LV pacing via the CS in the majority of patients and may be used in isolation or in con junction with right ventricular pacing for biventricular synchronization. (PACE 2000; 23[Pt. II] :1738-1740 left ventricular pacing, heart failure, ventricular synchronization, pacemaker lead