Figure 1.
NOGA endocardial mapping and cardiac magnetic resonance imaging (cMRI) of a pig with chronic myocardial ischemia.
A. 3D NOGA mapping showing anterior, anteroseptal, and apical myocardial infarction. Red indicates the infarct core (red arrow), the surrounding green-yellow area shows the border zone of infarction (yellow arrow). B. The corresponding unipolar voltage polar map. The color-coding is the same as in A. C. The bipolar voltage polar map of the same pig. Red indicates the transmural infarction (red arrow); yellow-green indicates the non-transmural infarction (yellow arrow), and blue-pink indicates normal myocardium. D. cMRI with late enhancement reveals the myocardial scar (red arrow). Long axis image. E. cMRI late enhancement short axis images with myocardial infarction (red arrow). Quantitative size of infarction was assessed by dividing of the myocardium to 8 slices from heart basis to apex (left upper corner). F. A cMRI transmurality polar map shows the transmural infarction (red arrow) with a surrounding area of non-transmural infarction (yellow arrow).
Figure 2.
Magnet resonance imaging- (MRI-) derived NOGA bipolar threshold values for infarct transmurality.
A. Iterative thresholding of voltage maps (left panel). The original NOGA maps were cropped to infarct areas, converted to a mV scale, then iteratively thresholded using 100 steps from 0.5 to 1.5 mV. The middle panel shows examples of the iterative thresholding process. The right panel shows the association between the area of infarction and the applied mV threshold. B. Voltage-threshold dependence of the correlation between NOGA maps and areas on an MRI. The maximum correlation coefficient is shown for each line plot. C. Histological correlations of transmural (left) and non-transmural (middle) infarctions and normal heart tissue (right). Samples were taken from areas with bipolar voltage values <0.8 mV, between 0.8–1.9 mV, and>1.9 mV with corresponding cMRI-LE transmurality values of>75%, 50%, and <25%, respectively. Magnification: 2x.
Table 1.
NOGA endocardial unipolar and bipolar map-derived cut-off values.
Figure 3.
Determination of the bipolar voltage (BiPV) cut-off value for calculating the transmural and non-transmural infarct size using unipolar voltage values.
A. Linear correlation between unipolar and bipolar voltage values. B. Part of the correlation showing the non-viable range defined as unipolar voltage values <5 mV. C. Receiver operator characteristics curve for determination of different bipolar voltage cut-off values. D. Display of bipolar maps using different cut-offs.
Figure 4.
Schematic illustration of the planimetric calculation of the size of the infarct core and the size of the border zone of the infarction with decreased viability in the NOGA endocardial mapping.
Red indicates the infarct core, and green-yellow indicates the surrounding area that has decreased viability.
Figure 5.
Schematic illustration of the planimetric calculation of the transmural and non-transmural infarct sizes as shown in polar maps from cardiac magnetic resonance imaging (cMRI) and NOGA endocardial mapping.
A. Planimetric calculations of the sizes of the transmural and non-transmural infarction by cMRI. B. Planimetric calculations of the sizes of the transmural and non-transmural infarction in a NOGA bipolar voltage map.
Figure 6.
Calculation of the overlapping ratio of the transmural plus the non-transmural infarction by cardiac magnetic resonance imaging (cMRI) and NOGA endocardial mapping.
A. cMRI transmurality polar map. B. NOGA bipolar polar map. C and D. Overlap of the cMRI and NOGA polar maps. a: The size of the transmural and non-transmural infarction by cMRI; b: the size of transmural and non-transmural infarction by NOGA bipolar mapping; c: overlap of the NOGA bipolar infarct shape on a cMRI polar map; d: overlap of the cMRI infarct shape on a NOGA bipolar map. The overlapping ratio was calculated as follows: (c+d)/(a+b).
Table 2.
Endocardial NOGA mapping results.
Table 3.
Results of cardiac magnetic resonance (cMRI) with late enhancement.
Figure 7.
Correlation between NOGA endocardial mapping and cardiac magnetic resonance imaging (cMRI) and statistical analysis of the determination of infarct size.
A. Regression equation between the size of the infarct core as determined on a unipolar voltage map (UPV) and as determined using late enhancement cMRI. B. Bland-Altman plot of the size of the infarct core as determined on a unipolar voltage map and the size as determined using late enhancement cMRI. Mean (black line) ±2SD (blue line).
Figure 8.
Correlation between NOGA endocardial mapping and cardiac magnetic resonance imaging (cMRI) and statistical analysis of the determinations of transmural and non-transmural infarction.
A. Regression equation between the size of the transmural infarction as determined on a bipolar voltage map and the size as determined using cMRI. B. Bland-Altman plot of the size of the transmural infarction as determined on a bipolar voltage map and the size as determined using cMRI. Mean (black line) ±2SD (blue line). C. Regression equation between the size of the non-transmural infarction as determined on a bipolar voltage map and the size as determined using cMRI. D. Bland-Altman plot of the size of the non-transmural infarction as determined on a bipolar voltage map and the size as determined using cMRI. Mean (black line) ±2SD (blue line).