BACKGROUND: Multipoint left ventricular (LV) pacing (MultiPoint Pacing [MPP], St Jude Medical, Sylmar, CA) in a single coronary sinus branch has been introduced as a novel means of cardiac resynchronization therapy (CRT). It is speculated that MPP improves LV function by capturing a larger LV tissue area, resulting in uniform wavefront propagation throughout the ventricles, in comparison to conventional biventricular pacing (BIV). OBJECTIVE: The purpose of this study was to evaluate MPP by means of contact mapping and hemodynamic measures to understand the underlying mechanisms and effects. METHODS: Ten patients with non-ischemic cardiomyopathy (mean age 69 ± 9 years; 6 men (60%); New York Heart Association heart failure class II or III; QRS duration 173 ± 20 ms; LV ejection fraction 27% ± 5%) received a CRT-defibrillator capable of MPP. After the implantation procedure, an acute pacing protocol was implemented, including 2 BIV and up to 9 MPP interventions. In all pacing interventions, LV electrical activation patterns and hemodynamics (dP/dtmax) were evaluated, and for each patient, both the resulting measures were compared between MPP and BIV interventions. RESULTS: Compared with BIV, MPP resulted in an increase in LV dP/dtmax (30% ± 13% vs. 25% ± 11%; P = .041), a reduction in QRS duration (22% ± 11% vs. 11% ± 11%; P = .01), and a decrease in total endocardial activation time (25% ± 15% vs. 10% ± 20%; P = .01). MPP resulted in a larger capture of LV mass during the first 25 ms (35% ± 22% vs. 16% ± 8%; P = .005) and during the first 50 ms (78% ± 27% vs. 60% ± 23%; P = .03) of pacing, suggesting a quicker wavefront propagation throughout the left ventricle. CONCLUSION: In this acute study, MPP in CRT improved both endocardial and surface electrical parameters and hemodynamics in comparison with BIV.
BACKGROUND: Multipoint left ventricular (LV) pacing (MultiPoint Pacing [MPP], St Jude Medical, Sylmar, CA) in a single coronary sinus branch has been introduced as a novel means of cardiac resynchronization therapy (CRT). It is speculated that MPP improves LV function by capturing a larger LV tissue area, resulting in uniform wavefront propagation throughout the ventricles, in comparison to conventional biventricular pacing (BIV). OBJECTIVE: The purpose of this study was to evaluate MPP by means of contact mapping and hemodynamic measures to understand the underlying mechanisms and effects. METHODS: Ten patients with non-ischemic cardiomyopathy (mean age 69 ± 9 years; 6 men (60%); New York Heart Association heart failure class II or III; QRS duration 173 ± 20 ms; LV ejection fraction 27% ± 5%) received a CRT-defibrillator capable of MPP. After the implantation procedure, an acute pacing protocol was implemented, including 2 BIV and up to 9 MPP interventions. In all pacing interventions, LV electrical activation patterns and hemodynamics (dP/dtmax) were evaluated, and for each patient, both the resulting measures were compared between MPP and BIV interventions. RESULTS: Compared with BIV, MPP resulted in an increase in LV dP/dtmax (30% ± 13% vs. 25% ± 11%; P = .041), a reduction in QRS duration (22% ± 11% vs. 11% ± 11%; P = .01), and a decrease in total endocardial activation time (25% ± 15% vs. 10% ± 20%; P = .01). MPP resulted in a larger capture of LV mass during the first 25 ms (35% ± 22% vs. 16% ± 8%; P = .005) and during the first 50 ms (78% ± 27% vs. 60% ± 23%; P = .03) of pacing, suggesting a quicker wavefront propagation throughout the left ventricle. CONCLUSION: In this acute study, MPP in CRT improved both endocardial and surface electrical parameters and hemodynamics in comparison with BIV.