Stimulation of the left ventricle through the coronary sinus with a newly developed ‘over the wire’ lead system — early experiences with lead handling and positioning

Aims This report describes the initial clinical results with a newly designed guiding catheter and an ‘over the wire’ pacing lead based on angiolasty technology to stimulate the left ventricle using the transvenous route via the coronary sinus (OTW-CV lead). Methods and Results In 75% of the 15 patients (6 males, 9 females, mean age of 53±9 years) with congestive heart failure, access to coronary sinus required less than 2 min; in one patient, the attempt failed. Mean R wave amplitudes plus or minus the standard deviation, measured at apical, mid-ventricular and basal positions in the anterior (11·4±9·2, 10·8±6·2, 9·3±6·3 mV) and lateral or posterior veins (10·1±10·7, 8·6±6·4, 7·7±4·3 mV) showed a trend favouring the apex without statistical significance. Pacing impedance, measured at the same sites and vein tributaries, ranged from 670±191 to 915±145 ohms. Pacing thresholds measured at apical and mid ventricular sites were significantly lower than at the base in the anterior vein 2·5±2·8 and 2·8±1·8 vs 5·6±2·7 V at 0·5 ms, P< 0·001). Thresholds in the lateral/posterior veins showed a similar trend but did not reach statistical significance (3·0±1·7, 3·6±1·4±1·8 V at 0·5 ms). In patients, in whom thresholds were determined in more than one vein, the ‘best’ mean threshold was 1·6±0·7 V. Conclusion The new ‘over the wire’ lead and guiding catheter system allows uncomplicated access to the coronary sinus and the depth of the coronary vein tributaries. Left ventricular sensing and pacing thresholds are acceptable for chronic use in implanted cardiac rhythm management systems.