Comparison of stimulation sites within left ventricular veins on the acute hemodynamic effects of cardiac resynchronization therapy

OBJECTIVES The purpose of this study was to study the acute hemodynamic effect of left ventricular (LV) stimulation sites within a coronary vein. BACKGROUND Access to LV stimulation sites for resynchronization therapy is achieved using specialized lead systems navigated through a coronary vein. The effects of stimulation in different coronary veins have been evaluated previously, but less is known about stimulation sites within a coronary vein. METHODS Twenty-four patients (New York Heart Association functional class II-IV, age 59 +/- 10 years, ejection fraction 21 +/- 7%, QRS 166 +/- 30 ms) were enrolled in the study. A novel over-the-wire lead system was used to access an anterior or lateral coronary vein. At each lead location, a randomized stimulation protocol was executed. Hemodynamic responses were evaluated using LV dP/dt(max). RESULTS The mean time to cannulate the coronary sinus and position the LV lead was 19 30 minutes and 17 +/- 18 minutes, respectively. Data from stimulation at two sites within a coronary vein were obtained in 19 patients (anterior vein 11; lateral vein 8). Of these patients, 14 (anterior vein 9; lateral vein 5) showed large improvement in dP/dt(max) (22%-25% in anterior vein, 37%-40% in lateral vein). Overall, there were no group differences in hemodynamic effects among different stimulation sites within a coronary vein, although significant variability among sites was observed in individuals. CONCLUSIONS Resynchronization therapy through a coronary vein improves acute hemodynamic function of heart failure patients with LV conduction disorder. There were no significant differences between basal and apical pacing sites for this group.