Towards cardiac and respiratory motion characterization from electrophysiology data for improved real time MR-integration

Electro-anatomical voltage mapping (EAM) is an invasive technique used for the identification of ventricular tachycardia (VT) substrate and subsequent guidance of VT ablation [1]. The mapping of VT substrate is very time consuming procedure, requires highly skilled electrophysiologist, is associated with patient risk and is an invasive procedure. Late gadolinium enhancement (LGE) MRI allows non-invasive evaluation of 3D structure of scar. Therefore, LGE has the potential to identify the VT substrate and can now be integrated in the current clinical platform for guidance of VT ablation as a roadmap. However, fusion of the two imaging modality is very challenging due to respiratory and cardiac motion during the mapping which results in large errors in data fusion. Our aim in this study is to develop a novel algorithm to detect the respiratory and cardiac-induced motion of the mapping catheter during the VT ablation to facilitate integration of LGE MRI to EAM data

High-Resolution Mapping of Ventricular Scar:Comparison Between Single and Multielectrode Catheters

BACKGROUND: Mapping resolution is influenced by electrode size and interelectrode spacing. The aims of this study were to establish normal electrogram criteria for 1mm multielectrode-mapping catheters (Pentaray(®)) in the ventricle and to compare its mapping resolution within scar to standard 3.5mm catheters (Smart-Touch Thermocool(®)). METHODS AND RESULTS: Three healthy swine and 11 swine with healed myocardial infarction underwent sequential mapping of the left ventricle with both catheters. Bipolar voltage amplitude in healthy tissue was similar between 3.5mm and 1mm multielectrode catheters with a 5(th) percentile of 1.61mV and 1.48mV, respectively. In swine with healed infarction, the total area of low bipolar voltage amplitude (defined as <1.5mV) was 22.5% smaller using 1mm multielectrode catheters (21.7cm(2) versus 28.0cm(2); p=0.003). This was more evident in the area of “dense scar” (bipolar amplitude <0.5mV) with a 47% smaller very low voltage area identified using 1mm electrode catheters (7.1cm(2) vs. 15.2cm(2); p=0.003). In this region, 1mm multielectrode catheters recorded higher voltage amplitude (0.72±0.81mV vs. 0.30±0.12mV, p<0.001). Importantly, 27% of these “dense scar” electrograms showed distinct triphasic electrograms when mapped using a 1mm multielectrode catheter compared with fractionated multicomponent electrogram recorded with the 3.5mm electrode catheter. In 8 mapped reentrant VTs, the circuits included regions of preserved myocardial tissue “channels” identified with 1mm multielectrode catheters but not 3.5mm electrode catheters. Pacing threshold within the area of low voltage was lower with 1mm electrode catheters (0.9±1.3mV vs. 3.8±3.7mV, p=0.001). CONCLUSIONS: Mapping with small closely spaced electrode catheters can improve mapping resolution within areas of low voltage

High-Resolution Mapping of Ventricular Scar

BACKGROUND: Mapping resolution is influenced by electrode size and interelectrode spacing. The aims of this study were to establish normal electrogram criteria for 1mm multielectrode-mapping catheters (Pentaray(®)) in the ventricle and to compare its mapping resolution within scar to standard 3.5mm catheters (Smart-Touch Thermocool(®)). METHODS AND RESULTS: Three healthy swine and 11 swine with healed myocardial infarction underwent sequential mapping of the left ventricle with both catheters. Bipolar voltage amplitude in healthy tissue was similar between 3.5mm and 1mm multielectrode catheters with a 5(th) percentile of 1.61mV and 1.48mV, respectively. In swine with healed infarction, the total area of low bipolar voltage amplitude (defined as <1.5mV) was 22.5% smaller using 1mm multielectrode catheters (21.7cm(2) versus 28.0cm(2); p=0.003). This was more evident in the area of “dense scar” (bipolar amplitude <0.5mV) with a 47% smaller very low voltage area identified using 1mm electrode catheters (7.1cm(2) vs. 15.2cm(2); p=0.003). In this region, 1mm multielectrode catheters recorded higher voltage amplitude (0.72±0.81mV vs. 0.30±0.12mV, p<0.001). Importantly, 27% of these “dense scar” electrograms showed distinct triphasic electrograms when mapped using a 1mm multielectrode catheter compared with fractionated multicomponent electrogram recorded with the 3.5mm electrode catheter. In 8 mapped reentrant VTs, the circuits included regions of preserved myocardial tissue “channels” identified with 1mm multielectrode catheters but not 3.5mm electrode catheters. Pacing threshold within the area of low voltage was lower with 1mm electrode catheters (0.9±1.3mV vs. 3.8±3.7mV, p=0.001). CONCLUSIONS: Mapping with small closely spaced electrode catheters can improve mapping resolution within areas of low voltage