Key result
Baseline ECGi activation times fail to predict CRT response but improve significantly in volumetric responders.
Why the study?
The relation between baseline acute electrophysiology metrics, their manipulation with CRT, and reverse remodeling was unclear.
Do baseline ECGi-derived parameters of electrical activation predict volumetric response to CRT in patients receiving CRT implants?
Observational (n=21)
Do baseline ECGi-derived parameters of electrical activation predict volumetric response to CRT in patients receiving CRT implants?
Baseline ECGi activation times do not predict CRT volumetric response, but acute improvements in these metrics during CRT optimization correlate with long-term reverse remodeling.
Baseline ECGi metrics should not guide CRT selection; acute improvements are hypothesis-generating for optimization.
Background Cardiac resynchronization therapy (CRT) produces acute changes in electric resynchronization that can be measured noninvasively with electrocardiographic body surface mapping (ECGi). The relation between baseline acute electrophysiology metrics and their manipulation with CRT and reverse remodeling is unclear. Objective To test (ECGi) derived parameters of electrical activation as predictors of volumetric response to CRT. Methods ECGi was performed in 21 patients directly following CRT implant. Activation parameters (left ventricular total activation time [LVtat], global biventricular total activation time [VVtat], global left/right ventricular electrical synchrony [VVsync], and global left ventricular dispersion of activation times [LVdisp]) were measured at baseline and following echocardiographically optimized CRT. Remodeling response (>15% reduction left ventricular end-systolic volume) was assessed 6 months post CRT. Results Patients were aged 68.9 ± 12.1 years, 81% were male, and 57% were ischemic. Baseline measures of dyssynchrony were more pronounced in left bundle branch block (LBBB) vs non-LBBB. ECGi demonstrated a trend of greater interventricular dyssynchrony between responders and nonresponders that did not reach statistical significance (VVsync: -45.7 ± 22.4 ms vs -25.1 ± 29.3 ms, P = .227). Remaining activation parameters were similar between responders and nonresponders (VVtat 101 ± 22.0 ms vs 98.9 ± 23.4 ms, P = .838; LVtat 86.4 ± 17.1 ms vs 85.1 ± 27.7 ms, P = .904; LVdisp 28.2 ± 6.3 ms vs 27.0 ± 8.7 ms, P = .726). In volumetric responders activation parameters were significantly improved with CRT compared to nonresponders: VV sync (-45.67 ± 22.41 ms vs 2.33±18.87 ms, P = .001), VVtat (101 ± 22.04 ms vs 71 ± 14.01 ms, P = .002), LVtat (86.44 ± 17.15 ms vs 67.67 ± 11.31 ms, P = .006), and LVdisp (28.22 ± 6.3 ms vs 21.56 ± 4.45 ms, P = .008). Conclusion Baseline ECGi activation times did not predict CRT volumetric response. Volumetric responders exhibited significant improvements in ECGi-derived metrics with CRT. ECGi does not select CRT candidates but may be a useful adjunct to guide left ventricle lead implants and to perform postimplant CRT optimization.
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Jackson et al. (2021) conducted an observational in Heart failure requiring cardiac resynchronization therapy (n=21). Baseline ECGi activation times was evaluated on Remodeling response (>15% reduction left ventricular end-systolic volume) at 6 months post CRT. Baseline ECGi activation times did not predict CRT volumetric response (VVsync P=0.227), but responders showed significant improvements in ECGi metrics with CRT (VVsync P=0.001).
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