The transmural activation interval: a new mapping tool to identify ventricular tachycardia substrates in right ventricular cardiomyopathy

Figures

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  Figure 1. Method. Panel A shows an example of paired points with a prolonged transmural activation interval (TAI) and normal maximal activation interval (MAI) duration. The first sharp bipolar peak deflection (SBP) (MAP 1–2 endo) coincides with the maximal downstroke of the endocardial unipolar signal (MAP 1 endo). Panel B illustrates an example of a prolonged TAI and MAI duration due a transmural and inlayer conduction delay. The first epicardial EGM component coincides exactly with the corresponding endocardial local activation time, and may be considered as farfield signal from the endocardium. The second component is a late and fragmented EGM.

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  Figure 2. Prolonged TAI in an ARVC patient. An endocardial electroanatomical map is colour coded for bipolar voltage (BV), and the corresponding epicardial BV map is displayed in a mesh view to show the proximity of coupled endocardial and epicardial point pairs. Also, the CT derived cardiac anatomy is integrated with the electroanatomical maps. The lower panels show the transmural activation measurements at two coupled point pairs with the endocardial (MAP 1–2 ENDO) and epicardial (MAP 1–2 EPI) bipolar electrograms. The left two panels show a prolonged transmural activation interval (TAI) and a similarly prolonged maximal activation interval (MAI) due to a prolonged transmural activation delay, without significant inlayer activation delay. The right two panels show a prolonged TAI and a further prolonged MAI due to a combination of transmural and inlayer activation delay.

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  Figure 3. Examples of prolonged TAI and MAI in ARVC patient. Electroanatomical endocardial bipolar voltage (BV) map and epicardial BV map displayed in a mesh view of a patient with ARVC with four examples of coupled points pairs with the endocardial (MAP 1–2 ENDO) and epicardial (MAP 1–2 EPI) bipolar electrograms and the local transmural activation interval (TAI) and maximal activation interval (MAI). Right upper panel: prolonged TAI and MAI due to a transmural activation delay; lower right: normal TAI and MAI; both left examples: prolonged TAI and MAI due to a combined transmural and inlayer activation delay.

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  Figure 4. Transmural activation interval and VT-related sites. Median and interquartile range for transmural activation interval (TAI) and maximal activation interval (MAI) for the three different point categories. VT-related sites (VT) had a longer TAI and MAI duration compared with normal points and scar points. The optimal cutoff between VT-related sites and scar sites is depicted by the dashed black line.