Important goals, when implanting a cardiac resynchronization therapy (CRT) system, are to reach a stable LV lead position in a suitable coronary sinus (CS) tributary associated with a low capture threshold and no extracardiac stimulation. The aim of this study was to assess the 2-year performance of a new preshaped lead designed for LV stimulation. The study enrolled 102 patients with heart failure and bundle branch block who underwent implantation of a CRT system, including a sheath-guided, unipolar, S-shaped LV lead placed in a CS tributary. At each follow-up the electrical parameters and CRT system related adverse events were recorded. Eight patients who underwent LV stimulation alone, versus 88 patients who received biventricular CRT systems, were analyzed separately. Access to the CS was reached in 98 patients, and the lead was permanently implanted in 96 (94%) patients. The overall procedural time was 98 +/- 28 minutes. During follow-up, three patients underwent reinterventions for phrenic nerve stimulation (n = 2) and hematoma (n = 1). The capture threshold at implantation was 1.4 +/- 0.9 V with LV versus 1.7 +/- 0.5 V with biventricular stimulation, and after a transient increase, remained between 1.6 and 1.9 V in both configurations. The device measured impedance was significantly higher with LV than with biventricular stimulation at the time of CRT system implantation (698 +/- 296 Omega vs 380 +/- 67 Omega, P < 0.05) and during follow-up. The initial R wave amplitude was 14.3 +/- 5.9 mV in LV versus 8.9 +/- 3.2 V in the biventricular configuration (NS) and 13.8 +/- 7 mV in LV versus 12.8 +/- 4.8 mV in the biventricular configuration at 24 months (NS). Implantation of the S-shaped LV lead for CRT was safe, expeditious, and associated with a high success rate and reliable long-term performance.
