Multisite, multipoint pacing

Abstract

Cardiac resynchronization therapy in patients with heart failure, reduced ejection fraction and prolonged QRS duration has become standard of care. Unfortunately, despite improvements in delivery of this treatment still approximately 30% of patients are non-responders. Among causes of this phenomenon one can find an inability to deliver hemodynamically effective left ventricular pacing. There were proposed several solutions to solve the problem, including: multisite RV pacing, multisite LV pacing, multipoint LV pacing. Multisite RV pacing (two RV leads positioned in RV: apex and RVOT), although causes some hemodynamic improvement in LVEF or distance in 6MWT and reduction of LVESD or number of hospitalizations in comparison to no paced patients, but its efficacy is significantly worse than normal CRT. So it should not be considered as an alternative to CRT even to surgically placed LV lead. Multisite LV pacing (two leads iv cardiac veins) gives significant benefits over standard CRT, especially in patients with poor heart vein system, which preclude optimal LV lead placement. Clinical benefits of this mode of therapy were observed in non-responders to classical CRT, and were proved in: higher responder rates, improved EF, VO2, distance in 6MWT, reduction of NYHA class, LVESV, LVEDD and increase of dP/dt. Multipoint LV pacing (different pacing point located on the same LV lead) is encouraging way of CRT delivery and does not require any additional lead. Benefits of MP pacing over classical CRT were proved in numerous trails in acute tests by improvement in dP/dt, increase in maximal strain rate, shortening of total activation time, reduction in QRS duration and after mid- and long term follow-up in reduction of LVESV, increase in EF, reduction of asynchrony and higher percentage of responders. Multipoint left ventricular pacing should be a standard of CRT delivery in first implantations.