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Figure 1 Electroanatomic Mapping Data
(A) shows an example of typical isopotential maps seen in both groups. Bipolar voltages <0.5 mV (VLZ) are depicted in red, with normal myocardium (>1.5 mV) represented by purple. The map on the left is from a 58-year-old man with severe ICM (EF 18%) after a large anterior MI 9 years earlier with no clinical arrhythmias. The VLZ accounts for only 9% of the LV surface area. A 67-year-old man with similarly severe ICM and spontaneous SMVT 13 years after anterior MI is shown on the right. A large confluent anteroapical VLZ accounting for 44% of the LV surface is present. The mean proportionate low-voltage areas are shown in B, with markedly larger VLZ and TLZ in Group 2. The mean signal amplitudes in these regions were significantly higher in the control patients (C). EF = ejection fraction; ICM = ischemic cardiomyopathy; LAO = left anterior oblique; LV = left ventricular; MI = myocardial infarction; SMVT = sustained monomorphic ventricular tachycardia; TLZ = total low-voltage zone; VLZ = very low-voltage zone.
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