Larger low voltage zone in endocardial unipolar map compared with that in epicardial bipolar map indicates difficulty in eliminating ventricular tachycardia by catheter ablation.
Patients with ischemic and non-ischemic cardiomyopathy often have substrate for ventricular tachycardia (VT) in the endocardium (ENDO), epicardium (EPI), and/or intramural. Although it has been reported that the ENDO unipolar (UNI) voltage map is useful in detecting EPI substrate, its feasibility to detect intramural scarring and its usefulness in radiofrequency catheter ablation (RFCA) remain unclear. To assess the relationship between the left ventricle (LV) ENDO UNI voltage map and the LV EPI bipolar (BIP) voltage map, and to determine the usefulness of the ENDO UNI voltage map to guide RFCA for VT in patients with cardiomyopathy undergoing combined ENDO- and EPI RFCA. Eleven patients with VT undergoing detailed ENDO and EPI electroanatomical mapping of the LV were included (mean age 59 ± 11 years, 9 men). We assessed the value of the LV ENDO UNI voltage map in identifying EPI and/or intramural substrate in these 11 patients with non-ischemic or ischemic cardiomyopathy. The underlying heart disease was dilated cardiomyopathy in 4 patients, cardiac sarcoidosis in 3, hypertrophic cardiomyopathy in 2, and ischemic heart disease in 2 patients. The mean LV ejection fraction was 24 ± 7 %. The low voltage zone (LVZ) was defined as <1.5 mV for LV ENDO BIP electrograms (EGMs), <8.3 mV for LV ENDO UNI EGMs, and <1.0 mV for LV EPI BIP EGMs. The surface area of each LVZ was measured. We also measured the LVZ of the spatial overlap between ENDO UNI and EPI BIP voltage maps using the transparency mode on CARTO software. We performed RFCA at the ENDO and EPI based on activation and/or substrate maps, targeting the LVZ and/or abnormal EGMs. The LVZ was present in the LV ENDO BIP voltage map in 10 of 11 patients (42 ± 33 cm(2)), and in the LV ENDO UNI voltage map in 10 of 11 patients (72 ± 45 cm(2)). The LVZ was present in the EPI BIP voltage map in 9 of 11 patients (70 ± 61 cm(2)), and the LVZ in the ENDO UNI voltage map was also seen in all 9 patients. The location of the LVZ in the EPI BIP map matched that in 45 ± 28 % of ENDO UNI voltage maps. The LVZ in the ENDO UNI voltage map was larger than that in the EPI BIP voltage map in 6 of 11 patients, and RFCA failed in 5 of these 6 patients. In the remaining 5 patients with a smaller LVZ in the ENDO UNI voltage map compared with the EPI BIP voltage map or no LVZ both at ENDO UNI and EPI BIP voltage map, VT was successfully eliminated in 4 of 5 patients. The LV ENDO UNI voltage map is useful in detecting EPI substrate in patients with cardiomyopathy. A larger LVZ in the ENDO UNI voltage map compared to that in the EPI BIP voltage map may indicate the presence of intramural substrate, which leads to difficulty in eliminating VT, even with combined ENDO- and EPI RFCA.
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan. kojimiya@tempo.ocn.ne.jp.|Department of Advanced Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan. kojimiya@tempo.ocn.ne.jp.
Koji
K
Miyamoto
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.
Takashi
T
Noda
Department of Cardiology, Tokyo Medical University Hachioji Medical Center, Tokyo, Japan.
Kazuhiro
K
Satomi
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.
Mitsuru
M
Wada
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.
Ikutaro
I
Nakajima
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.
Kohei
K
Ishibashi
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.
Hideo
H
Okamura
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.
Teruo
T
Noguchi
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.|Department of Advanced Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Toshihisa
T
Anzai
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.|Department of Advanced Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Satoshi
S
Yasuda
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.|Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Hisao
H
Ogawa
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.|Department of Advanced Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.|Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan.
Wataru
W
Shimizu
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.
Takeshi
T
Aiba
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.
Shiro
S
Kamakura
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan.|Department of Advanced Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Kengo
K
Kusano
D000368:Aged; D009202:Cardiomyopathies / Q000150:complications*; D017115:Catheter Ablation; D002921:Cicatrix / Q000503:physiopathology; D022062:Electrophysiologic Techniques, Cardiac; D004699:Endocardium / Q000601:surgery; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications*; D010496:Pericardium / Q000601:surgery; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000601:surgery*; D016277:Ventricular Function, Left
Catheter ablation; Endocardium; Epicardium; Low voltage zone; Unipolar; Ventricular tachycardia