Left ventricular mechanical dyssynchrony in patient with CAD: The Saga continues
- PDF / 186,781 Bytes
- 4 Pages / 593.972 x 792 pts Page_size
- 49 Downloads / 179 Views
Division of Cardiovascular Medicine, Clemenceau Medical Center, Beirut, Lebanon
Received Jul 16, 2020; accepted Jul 16, 2020 doi:10.1007/s12350-020-02318-7
See related article, doi:https://doi.org/10. 1007/s12350-020-02316-9.
Left ventricular mechanical dyssynchrony (LVMD) by phase analysis of gated single-photon emission computed tomography (SPECT) was initially introduced by Chen et al in 2005 as a simple reliable tool that is reproducible and repeatable, performed retrospectively on previously acquired gated images, and without the need for additional imaging.1,2 LVMD has been used to identify patients with cardiomyopathy who would benefit from cardiac resynchronization therapy (CRT) beyond electrical dyssynchrony and ejection fraction criteria, and based on phase standard deviation cut-offs,3,4 contraction patterns (U versus non-U shape),5,6 and concordance of LV lead placement with site of latest mechanical contraction.7 The software, now commercially available, has also been used to differentiate ischemic versus nonischemic cardiomyopathy 8 and for many other clinical indications.9 Furthermore, it is a powerful prognostic tool validated in different cohorts.9-15 There have been many studies evaluating a potential role for LVMD in patients with coronary artery disease (CAD). Indeed, Gimelli et al showed that 38% of patients with extensive CAD have significant LVMD which is dependent on the presence of myocardial perfusion abnormalities and LV end-systolic volume.16 In the current manuscript, Ha¨ma¨la¨inen et al from Kuopio University Hospital, Finland, evaluated LVMD in 326 patients with CAD.17 LVMD was assessed with the
Funding None. Reprint requests: Wael AlJaroudi, MD, FASNC, Division of Cardiovascular Medicine, Clemenceau Medical Center, Beirut, Lebanon; [email protected] J Nucl Cardiol 1071-3581/$34.00 Copyright Ó 2020 American Society of Nuclear Cardiology.
phase analysis of ECG-gated myocardial SPECT and LVMD was described with phase histogram bandwidth, standard deviation or entropy values above limit of the highest normal using a control group as a reference. Almost a third of patients with CAD had LVMD. The size of the myocardial scar (fixed perfusion defect) and ischemia (reversible perfusion defect) correlated significantly with all dyssynchrony indices (P \ 0.001 for all). Furthermore, on multivariate analysis, independent predictors of LVMD were myocardial infarction scar (P = 0.004), ischemia extent (P = 0.003), and QRS duration (P = 0.003).17 In a subgroup analysis, Ha¨ma¨la¨inen et al also showed that patients with abnormal MPI in 2 or more vessel territories had more extensive LVMD.17 The effect of stress testing on LVMD is interesting. It has been postulated that significant stress-induced ischemia may cause myocardial stunning that translates into new or worsening LVMD on stress-gated images. Indeed, Hida et al nicely demonstrated that early post-stress worsening of LVMD identified patients with multivessel ischemia.18 However, few controversial issues remain regarding the significa
Data Loading...
