Interrelationships between interventricular electrical delays in cardiac resynchronization therapy

Abstract

Introduction In cardiac resynchronization therapy, pacing the left ventricle (LV) at sites of prolonged electrical delay is associated with better outcomes. We sought to characterize the interrelationships between intrinsic, right‐ventricular (RV)‐paced, and LV‐paced interventricular delays. Methods and Results The following electrical timings were measured at implantation for all electrodes of the LV quadripolar leads: QLV, interventricular delay in intrinsic rhythm (RVs‐LVs), in RV‐paced rhythm (RVp‐LVs), and in LV‐paced rhythm (LVp‐RVs). We included 32 patients (78% men, age 72 years, LV ejection fraction 29%, left bundle branch block 84%). QLV and RVs‐LVs were correlated (R2 = .72, p < .0001), as were RVs‐LVs and RVp‐LVs (R2 = .27, p = .002) and RVp‐LVs and LVp‐RVs (R2 = .60, p < .001). Direction of activation along the four LV lead electrodes was concordant between RVs‐LVs and RVp‐LVs in only 17 (53%) patients. The latest‐activated electrodes in RVs‐LVs and RVp‐LVs were concordant in 26 (81%) patients, adjacent in 3 (9%) patients, and remote in 3 (9%) patients. Biventricular‐paced QRS duration varied by more than 10 ms between the two electrodes in half of the patients with dissimilar latest electrodes. Among the seven echocardiographic nonresponders at 6 months, the programmed electrode was remote from the latest electrode in RVs‐LVs in five patients and in RVp‐LVs in three patients. Conclusion Intrinsic and RV‐paced interventricular electrical delays are correlated, but there is substantial heterogeneity between patients. The latest‐activated electrode may be different between RVs‐LVs and RVp‐LVs, and this might have important implications in selecting the optimal LV vector.

Intracardiac conduction time as a predictor of cardiac resynchronization therapy response: Results of the BIO|SELECT pilot study

“…Moubarak et al 1 found a stronger correlation (R 2 =0.27) between RVp-LVs and RVs-LVs than we did (R 2 =0.07). This is probably related to the fact that they assumed data for four different poles of the same quadripolar LV lead to be independent, allowing each of 32 patients to contribute four pairs of values.…”

“…In a recent study, also prolonged RVp-LVs interval correlated with CRT benefit. 1 No data exist on the predictive value of LVp-LVs interval, which may reflect scarring of the posterior or lateral LV wall or other conditions potentially influencing CRT response and clinical outcome. 1,2,6 In the present study, we analyzed the interrelationship between intrinsic, RV-paced, and LV-paced conduction delays and assessed their association with CRT response and potential consequence on LV electrode selection in CRT patients with a quadripolar LV lead.…”

“…1 No data exist on the predictive value of LVp-LVs interval, which may reflect scarring of the posterior or lateral LV wall or other conditions potentially influencing CRT response and clinical outcome. 1,2,6 In the present study, we analyzed the interrelationship between intrinsic, RV-paced, and LV-paced conduction delays and assessed their association with CRT response and potential consequence on LV electrode selection in CRT patients with a quadripolar LV lead. Since single measures of CRT response, such as LV end-systolic volume (LVESV) decrease or LV ejection fraction (LVEF) increase, can be affected by a considerable measurement error, we combined four indicators of heart failure development: LVESV, LVEF, brain natriuretic peptide (BNP) level, and New York Heart Association (NYHA) functional class to obtain a more stable composite index of CRT response.…”

Ventricular activation patterns during intrinsic conduction and right ventricular pacing in cardiac resynchronization therapy patients

“…A single-center study of 32 patients recently showed a mismatch in activation order between intrinsic conduction and RV pacing in fewer patients (47% vs. 72.7%), but considered activation times within 10 ms as simultaneous. 14 Nonetheless, the heterogeneity in RV-LV times between intrinsic conduction and RV pacing agree with the findings of this study, but further evaluation is needed to determine whether intrinsic conduction or RV pacing provides the most suitable conduction pathway to guide LV pacing site selection.…”

Paced or sensed conduction time to determine programming with cardiac resynchronization therapy: The PASED‐CRT Trial

“…[19][20][21][22][23][24] Although most studies have identified optimal LV sites at those with the longest sensed IVCD as measured from the earliest surface ECG deflection of the onset of ventricular activation to the latest LV bipolar electrogram activation time during conducted beats known as Q-LV time, while others have observed the latest paced IVCD measured from the RV pacing to the latest LV activation as the ideal LV pacing site. 25 This study aimed to compare the clinical effectiveness of programming the latest paced versus sensed LV lead poles in patients with CRT device.…”