Table 2: The Identification of Arrhythmogenic Substrate by Different Image Modalities.
| Studies | Patient Population | Image Modalities | Multimodal Imaging Substrate | Electroanatomical Substrate | Correlation of Images and Electroanatomical Substrate |
|---|---|---|---|---|---|
| Dickfeld et al. 2008[88] | ICM (n=12) NICM (n=2) |
PET-CT Thallium scan or rubidium PET |
Scar: FDG to blood flow match pattern Diseased/hibernating myocardium: FDG to blood flow mismatch pattern |
BV <0.5 mV: scar; 0.5–1.5 mV: abnormal myocardium |
PET/CT-derived scar maps correlate with voltage map (r=0.89; p<0.05) Scar size, location and border zone predict high resolution voltage map channels (r=0.87; p<0.05). |
| Bogun et al. 2009[19] | NICM (n=29) | CMR | Two blinded observers identify LV scar and manually contoured for quantification | BV <1.5 mV: scar (LVA) | CMR-derived scar size correlates with endocardial scar size (BV <1 mV: r=0.96; p<0.0001; BV <1.5mV: r=0.94, p<0.0001) |
| Santangeli et al. 2011[69] | ARVC (n=18) Myocarditis (n=13) Idiopathic RV outflow tract (n=5) |
CMR | Experienced radiologist blindly identifies RV scar | BV <0.5 mV: scar; 0.5–1.5 mV: border zone |
Scar ≥20% of the RV area is the best cutoff value to detect LGE (Sen: 83%, Spe: 92%) |
| Spears et al. 2012[87] | NICM (n=10) | CMR | Core scar: SI ≥50% of maximal myocardial SI Grey scar: SI > the maximum remote myocardial SI, but <50% of the maximal SI (full width at half-maximum) |
N/R | BV >1.9 mV and UV <6.7 mV: 91% NPV for detecting non-endocardial scar from no scar or endocardial scar |
| Cochet et al. 2013[62] | ICM (n=3) NICM (n=3) Myocarditis (n=2) IDCM (n=1) |
CMR CT |
Scar: 50–100% of maximal myocardial SI Grey zone: 35–50% of maximal myocardial SI Wall-thinning: LV end-diastolic wall thickness <5 mm |
BV <1.5 mV as LVA and LAVA | NICM: poor overlap of LGE CMR-defined substrate with EAVM LVA Wall-thinning matched areas of LVA with an overlap of 63 ± 21% Myocarditis: good overlap of sub-epicardial LGE with LVA (scar: 83 ± 24%; grey zone: 92 ± 12%) Wall-thinning was not found despite the presence of LV epicardial low voltage. |
| Desjardins et al. 2013[60] | NICM (n=15) | CMR | Two blinded observers identified scar | BV <1.5 mV: LVA | 1.55 mV for BV (AUC=0.69, Sen: 61%, Spe: 66%) and 6.78 mV for UV (AUC=0.78, Sen: 76%, Spe: 69%) are best cutoff values for the identification of intramural substrate |
| Piers et al. 2013[25] | NICM (n=10) | CMR CT |
Scar: >35% maximal myocardial SI Fat thickness |
BV <1.5 mV: LVA | 1.81 mV for BV (AUC: 0.73, Sen: 59%, Spe: 78%) and 7.95 mV for UV (AUC: 0.79, Sen: 80%, Spe: 72%) enables to distinguish scar from normal myocardium in areas <2.8 mm fat |
| Esposito et al. 2016[24] | NICM (n=19) | CT | Visually defined delayed enhanced segments as scar and the scar transmurality | BV ≤1.5 mV UV ≤8 mV (for LV) Late potentials |
Delayed enhancement segments on CT correlated with low voltage area (Sen: 76%, Spe: 86%, NPV: 95%) |
| Liang et al. 2018[61] | NICM (n=95) | CMR | Scar: full width at half-maximum method | BV ≤1.5 mV UV ≤8.3 mV |
4.8 mV for UV cutoff value provides best correlation with LGE on CMR (AUC: 0.75, Sen: 75%, Spe: 70%) |
| Xie et al. 2018[70] | ARVC (n=10) | CMR | N/R | Epicardium: BV ≤0.5 mV: dense scar BV >1 mV: normal myocardium |
SI Z score >0.05 correlates with BV <0.5 mV and <−0.16 correlates with BV >1 mV SI Z score >0.05 identifies delayed potentials in the RV epicardium (Sen: 72%, Spe: 56%) |
ARVC = arrhythmogenic right ventricular cardiomyopathy; BV = bipolar voltage; CMR = cardiac MRI; FDG = fludeoxyglucose; ICM = ischaemic cardiomyopathy; IDCM = idiopathic dilated cardiomyopathy; LAVA = local abnormal ventricular activities; LGE = late gadolinium enhancement; LV = left ventricle; LVA = low-voltage area; N/R = not reported; NICM = non-ischaemic cardiomyopathy; NPV = negative predictive value; RV = right ventricle; Sen = Sensitivity; SI = signal intensity; Spe = Specificity; UV = unipolar voltage.