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Ventricular Pacing Lead Location Alters Systemic Hemodynamics and Left Ventricular Function in Patients With and Without Reduced Ejection Fraction

Randy Lieberman, MD^_*,_*, Luigi Padeletti, MD, Jan Schreuder, MD, Kenneth Jackson, PA^_*, Antonio Michelucci, MD, Andrea Colella, MD, William Eastman, MS, Sergio Valsecchi, BS and Douglas A. Hettrick, PhD

^_* Harper Hospital, Detroit, Michigan
University of Florence, Florence, Italy
San Raffaele University Hospital, Milan, Italy
Medtronic, Inc., Minneapolis, Minnesota

View larger version (15K): [in a new window]   Figure 1 Representative steady-state pressure-volume diagrams from 1 patient with an ejection fraction (EF) 40% (A) and EF <40% (B). Groups during atrial overdrive pacing and during dual-chamber pacing and dual chamber biventricular (BiV) pacing. (C) Comparison of basal atrial overdrive (AAI) data from A and B. Rectangle in part A illustrates calculation of global cycle efficiency. Cycle efficiency is equal to the percentage of area occupied by the actual pressure volume loop within a rectangle determined by left ventricular (LV) pulse pressure and LV pulse volume. LVF = left ventricular free wall; RAA = right atrial; RVA = right ventricular apex; RVF = right ventricular outflow tract free wall; RVS = right ventricular outflow tract septum.

View larger version (17K): [in a new window]   Figure 2 Alterations in LV stroke work (SW) (A), stroke volume (SV) (B), and +dP/dtMAX (C) during AAI and alternate site ventricular pacing. *p < 0.05 versus EF 40%, p < 0.05 versus AAI (RM ANOVA, Dunnet's comparison), p < 0.05 versus RVA, p < 0.05 versus RVS, ||p < 0.05 versus RVF (2-way RM ANOVA, Student-Neuman-Keuls comparison). Other abbreviations as in Figure 1.

View larger version (16K): [in a new window]   Figure 3 Alterations in LV end-systolic pressure (LVESP) (A), LV end-diastolic volume (LVEDV) (B), and cycle efficiency (CE), an index of LV synchrony (C) during AAI and alternate site ventricular pacing. *p < 0.05 versus EF 40%, p < 0.05 versus AAI, p < 0.05 versus RVA (RM ANOVA, Dunnet's comparison), p < 0.05 versus RVS, ||p < 0.05 versus RVF (2-way RM ANOVA, Student-Neuman-Keuls comparison). Other abbreviations as in Figures 1 and 2.

View larger version (28K): [in a new window]   Figure 4 Regional and global LV pressure volume loops during atrial overdrive and dual chamber pacing from different ventricular sites in a representative patient with EF <40%. Regions are numbered from apex (1) to base (6), corresponding to the sequential volume channels along the axis of the conductance catheter. These individual signals form the global pressure-volume loop when summed. Note that RV pacing from different sites changes the regional contributions to the global pressure volume loop. Right ventricular apex pacing has a greater impact on the apical segments. Conversely, RVS and RVF pacing primarily distort the basal segment. Left ventricular and biventricular pacing result in more homogenous distribution of regional work. Abbreviations as in Figures 1 and 2.

View larger version (11K): [in a new window]   Figure 5 Distribution of regional cycle efficiency within the LV. Regional cycle efficiency was higher for the most apical and basal volume segment at each pacing site in patients with EF <40% (top) and EF 40% (bottom). Regional cycle efficiency depended on pacing site and varied by region within pacing site in the group with EF <40% (top), but not the group with EF 40% (bottom). In general, RVA pacing attenuated the apical segmental synchrony, and RVFW and RVS pacing attenuated the basal segmental synchrony in the with EF 40% group. Data are mean ± SE (2-way RM ANOVA Student-Neuman-Keuls comparison). Abbreviations as in Figures 1 and 2.

View larger version (19K): [in a new window]   Figure 6 Stroke work (SW) (top) and +dP/dtMAX (bottom) at the RV pacing site (RVA, RVS, or RVF), resulting in maximum (MAX RV) and minimum (MIN RV) stroke work or +dP/dtMAX compared with stroke work measured during control (AAI). The site of maximal stroke work or +dP/dtMAX was not different from AAI. Thus, RV pacing does not necessitate attenuated hemodynamics. However, the optimal RV site varied between patients. *p < 0.05 versus AAI, (RM ANOVA with Student-Neuman-Keuls post-hoc comparison). Other abbreviations as in Figures 1 and 2.