Reproducibility of global and segmental myocardial strain using cine DENSE at 3 T: a multicenter cardiovascular magnetic resonance study in healthy subjects and patients with heart disease

BACKGROUND: While multiple cardiovascular magnetic resonance (CMR) methods provide excellent reproducibility of global circumferential and global longitudinal strain, achieving highly reproducible segmental strain is more challenging. Previous single-center studies have demonstrated excellent reproducibility of displacement encoding with stimulated echoes (DENSE) segmental circumferential strain. The present study evaluated the reproducibility of DENSE for measurement of whole-slice or global circumferential (Ecc), longitudinal (Ell) and radial (Err) strain, torsion, and segmental Ecc at multiple centers. METHODS: Six centers participated and a total of 81 subjects were studied, including 60 healthy subjects and 21 patients with various types of heart disease. CMR utilized 3 T scanners, and cine DENSE images were acquired in three short-axis planes and in the four-chamber long-axis view. During one imaging session, each subject underwent two separate DENSE scans to assess inter-scan reproducibility. Each subject was taken out of the scanner and repositioned between the scans. Intra-user, inter-user-same-site, inter-user-different-site, and inter-user-Human-Deep-Learning (DL) comparisons assessed the reproducibility of different users analyzing the same data. Inter-scan comparisons assessed the reproducibility of DENSE from scan to scan. The reproducibility of whole-slice or global Ecc, Ell and Err, torsion, and segmental Ecc were quantified using Bland-Altman analysis, the coefficient of variation (CV), and the intraclass correlation coefficient (ICC). CV was considered excellent for CV ≤ 10%, good for 10%  40. ICC values were considered excellent for ICC > 0.74, good for ICC 0.6 < ICC ≤ 0.74, fair for ICC 0.4 < ICC ≤ 0.59, poor for ICC < 0.4. RESULTS: Based on CV and ICC, segmental Ecc provided excellent intra-user, inter-user-same-site, inter-user-different-site, inter-user-Human-DL reproducibility and good-excellent inter-scan reproducibility. Whole-slice Ecc and global Ell provided excellent intra-user, inter-user-same-site, inter-user-different-site, inter-user-Human-DL and inter-scan reproducibility. The reproducibility of torsion was good-excellent for all comparisons. For whole-slice Err, CV was in the fair-good range, and ICC was in the good-excellent range. CONCLUSIONS: Multicenter data show that 3 T CMR DENSE provides highly reproducible whole-slice and segmental Ecc, global Ell, and torsion measurements in healthy subjects and heart disease patients

Electrical and Mechanical Ventricular Activation During Left Bundle Branch Block and Resynchronization

Cardiac resynchronization therapy (CRT) aims to treat selected heart failure patients suffering from conduction abnormalities with left bundle branch block (LBBB) as the culprit disease. LBBB remained largely underinvestigated until it became apparent that the amount of response to CRT was heterogeneous and that the therapy and underlying pathology were thus incompletely understood. In this review, current knowledge concerning activation in LBBB and during biventricular pacing will be explored and applied to current CRT practice, highlighting novel ways to better measure and treat the electrical substrate

Ventricular dyssynchrony assessed by gated myocardial perfusion SPECT using a geometrical approach: a feasibility study

Cardiovascular Aspects of Radiolog

The “Missing” Link Between Acute Hemodynamic Effect and Clinical Response

The hemodynamic, mechanical and electrical effects of cardiac resynchronization therapy (CRT) occur immediate and are lasting as long as CRT is delivered. Therefore, it is reasonable to assume that acute hemodynamic effects should predict long-term outcome. However, in the literature there is more evidence against than in favour of this idea. This raises the question of what factor(s) do relate to the benefit of CRT. There is increasing evidence that dyssynchrony, presumably through the resultant abnormal local mechanical behaviour, induces extensive remodelling, comprising structure, as well as electrophysiological and contractile processes. Resynchronization has been shown to reverse these processes, even in cases of limited hemodynamic improvement. These data may indicate the need for a paradigm shift in order to achieve maximal long-term CRT response

Mechano-energetics of the asynchronous and resynchronized heart

Abnormal electrical activation of the ventricles creates major abnormalities in cardiac mechanics. Local contraction patterns, as reflected by measurements of local strain, are not only out of phase, but often also show opposing length changes in early and late activated regions. As a consequence, the efficiency of cardiac pump function (the amount of stroke work generated by a unit of oxygen consumed) is approximately 30% lower in asynchronous than in synchronous hearts. Moreover, the amount of work performed in myocardial segments becomes considerably larger in late than in early activated regions. Cardiac Resynchronization Therapy (CRT) improves mechano-energetics of the previously asynchronous heart in various ways: it alleviates impediment of the abnormal contraction on blood flow, it increases myocardial efficiency, it recruits contraction in the previously early activated septum and it creates a more uniform distribution of myocardial blood flow. These factors act together to increase the range of cardiac work that can be delivered by the patients’ heart, an effect that can explain the increased exercise tolerance and quality of life reported in several CRT trials