TY - JOUR
T1 - The influence of fat thickness on the human epicardial bipolar electrogram characteristics
T2 - Measurements on patients undergoing open-heart surgery
AU - Saba, Magdi M.
AU - Akella, Jagan
AU - Gammie, James
AU - Poston, Robert
AU - Johnson, Anthony
AU - Hood, Robert E.
AU - Dickfeld, Timm Michael
AU - Shorofsky, Stephen R.
PY - 2009/7
Y1 - 2009/7
N2 - AimsReference values exist for endocardial but not for epicardial (EPI) substrate mapping in cases of cardiomyopathy-associated ventricular tachycardia. We sought to establish such values for EPI electrogram voltage, including areas with overlying fat.Methods and resultsTen patients (six males) undergoing cardiac surgery were studied. After opening the pericardium, the distal bipole of an electrophysiology catheter was placed tangential to the EPI surface to obtain an electrogram recording. The bipole was tangentially rotated 90° and the higher of the two amplitudes (mV) was taken as the local amplitude. Recordings were taken from normal left and right ventricular myocardium (n = 26 data points each), over thick (≥0.5 cm) fat at both ventricular bases (n = 16) and thin (<0.5 cm) fat at the mid-ventricular level (n = 32). A total of 100 recordings (mean 10/patient) were analysed. Four patients underwent valvular surgery, three bypass surgery, and three combined procedures. Mean age was 61.7 ± 10.4 years and mean left ventricular ejection fraction was 46 ± 12. Electrogram amplitude was inversely related to EPI fat thickness. Over thick fat, 31 of recordings were <0.5 mV.ConclusionHuman EPI electrogram amplitude varies by ventricular chamber and significantly by EPI fat thickness. A cut-off of 0.5 mV to define 'scar' will include normal areas with thick overlying fat. EPI substrate maps should include data on EPI fat thickness for higher specificity.
AB - AimsReference values exist for endocardial but not for epicardial (EPI) substrate mapping in cases of cardiomyopathy-associated ventricular tachycardia. We sought to establish such values for EPI electrogram voltage, including areas with overlying fat.Methods and resultsTen patients (six males) undergoing cardiac surgery were studied. After opening the pericardium, the distal bipole of an electrophysiology catheter was placed tangential to the EPI surface to obtain an electrogram recording. The bipole was tangentially rotated 90° and the higher of the two amplitudes (mV) was taken as the local amplitude. Recordings were taken from normal left and right ventricular myocardium (n = 26 data points each), over thick (≥0.5 cm) fat at both ventricular bases (n = 16) and thin (<0.5 cm) fat at the mid-ventricular level (n = 32). A total of 100 recordings (mean 10/patient) were analysed. Four patients underwent valvular surgery, three bypass surgery, and three combined procedures. Mean age was 61.7 ± 10.4 years and mean left ventricular ejection fraction was 46 ± 12. Electrogram amplitude was inversely related to EPI fat thickness. Over thick fat, 31 of recordings were <0.5 mV.ConclusionHuman EPI electrogram amplitude varies by ventricular chamber and significantly by EPI fat thickness. A cut-off of 0.5 mV to define 'scar' will include normal areas with thick overlying fat. EPI substrate maps should include data on EPI fat thickness for higher specificity.
KW - Ablation
KW - Electrogram amplitude
KW - Epicardial
KW - Epicardial fat
KW - Ventricular tachycardia
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U2 - 10.1093/europace/eup156
DO - 10.1093/europace/eup156
M3 - Article
C2 - 19546189
AN - SCOPUS:67650889083
SN - 1099-5129
VL - 11
SP - 949
EP - 953
JO - Europace
JF - Europace
IS - 7
ER -