The influence of scar on the spatio-temporal relationship between electrical and mechanical activation in heart failure patients

Abstract

Aims The aim of this study was to determine the relationship between electrical and mechanical activation in heart failure (HF) patients and whether electromechanical coupling is affected by scar. Methods and results Seventy HF patients referred for cardiac resynchronization therapy or biological therapy underwent endocardial anatomo-electromechanical mapping (AEMM) and delayed-enhancement magnetic resonance (CMR) scans. Area strain and activation times were derived from AEMM data, allowing to correlate mechanical and electrical activation in time and space with unprecedented accuracy. Special attention was paid to the effect of presence of CMR-evidenced scar. Patients were divided into a scar (n = 43) and a non-scar group (n–27). Correlation between time of electrical and mechanical activation was stronger in the non-scar compared to the scar group [R = 0.84 (0.72–0.89) vs. 0.74 (0.52–0.88), respectively; P = 0.01]. The overlap between latest electrical and mechanical activation areas was larger in the absence than in presence of scar [72% (54–81) vs. 56% (36–73), respectively; P = 0.02], with smaller distance between the centroids of the two regions [10.7 (4.9–17.4) vs. 20.3 (6.9–29.4) % of left ventricular radius, P = 0.02]. Conclusion Scar decreases the association between electrical and mechanical activation, even when scar is remote from late activated regions.

Local electromechanical alterations determine the left ventricle rotational dynamics in CRT-eligible heart failure patients

“…As of many comparisons in this study, we found an internal heavier burden in the midseptal region of Group B, which is also the region in which the mechanical activation front splits in two, lingering before activating the neighboring apical and anterolateral regions. Maffesanti et al showed, with a similar setup to the one presented here, how a significant scar burden can significantly alter electromechanical synchronization and activation centroids 28 . This is accordance with our findings, although we could not distinguish between significant and non-significant scar burden, due to small sample size.…”

“…Importantly, ischemic HFrEF with concomitant LBBB may result in remodeling of ventricular EM coupling and geometry, disrupting LV mechanical activity and rotation pattern [25][26][27] . Remarkably, these changes can affect myocardium proximal to the ischemic region, as well as the remote one 28 . Similarly to our findings, Paoletti Perini et al 4 demonstrated, that, in patient with HF and co-existing LBBB, reduction of LV apex-basal rotation and www.nature.com/scientificreports/ global twist was associated with segmental rotational dyssynchrony.…”

“…Late gadolinium-enhanced cardiac MRI. Cardiovascular magnetic resonance imaging was performed as described by Maffesanti et al 28 Briefly, patients (5 for Group A and 20 for Group B) were scanned using a 1.5 T scanner (SIGNA, GE Medical Systems, USA) equipped with standard torso coil. Short-axis late gadolinium enhancement (LGE) images were obtained 7-12 min after the intravenous bolus injection of gadolinium (0.2 mmol/kg body weight).…”

Optimizing lead placement for pacing in dyssynchronous heart failure: The patient in the lead

“…13 Importantly, the extent of electromechanical uncoupling is variable and dependent on electrical and nonelectrical substrates, including regional hypocontractility and myocardial scar (Figure 2). 7,14 Here, lack of coupling implies electrical depolarization of a cardiac segment without synchronous myocardial fiber shortening. Due to uncoupling, however, sites of latest mechanical activation occur more frequently in a nonlaterally located segment than electrical activation, which complicates selection of optimal transvenous LVLP.…”

“…Due to uncoupling, however, sites of latest mechanical activation occur more frequently in a nonlaterally located segment than electrical activation, which complicates selection of optimal transvenous LVLP. 14 Based on our understanding of conduction disorders that cause dyssynchrony, 2 distinct approaches to enhance LVLP in dyssynchronous HF can be proposed (Figure 1).…”