visualized continuously, thereby decreasing the need for fluoroscopy and administration of intrave- nous contrast. 1. Marrouche NF, Martin DO, Wazni O, Gillinov AM, Klein A, Bhargava M, Saad E, Bash D, Yamada H, Jaber W, et al. Phased-array intracardiac echocar- diography monitoring during pulmonary vein isolation in patients with atrial fibrillation: impact on outcome and complications. Circulation 2003;107:2710 – 2716. 2. Saad EB, Cole CR, Marrouche NF, Dresing TJ, Perez-Lugones A, Saliba WI, Schweikert RA, Klein A, Rodriguez L, Grimm R, et al. Use of intracardiac echocardiography for prediction of chronic pulmonary vein stenosis after ablation of atrial fibrillation. J Cardiovasc Electrophysiol 2002;13:986 –989. 3. Ren JF, Marchlinski FE, Callans DJ, Zado ES. Intracardiac Doppler echocar- diographic quantification of pulmonary vein flow velocity: an effective technique for monitoring pulmonary vein ostia narrowing during focal atrial fibrillation ablation. J Cardiovasc Electrophysiol 2002;13:1076 –1081. 4. Mangrum JM, Mounsey JP, Kok LC, DiMarco JP, Haines DE. Intracardiac echocardiography-guided, anatomically based radiofrequency ablation of focal atrial fibrillation originating from pulmonary veins. J Am Coll Cardiol 2002;39: 1964 –1972. 5. Johnson SB, Seward JB, Packer DL. Phased-array intracardiac echocardiog- raphy for guiding transseptal catheter placement: utility and learning curve. Pacing Clin Electrophysiol 2002;25:402–407. 6. Epstein LM, Smith T, TenHoff H. Nonfluoroscopic transseptal catheterization: safety and efficacy of intracardiac echocardiographic guidance. J Cardiovasc Electrophysiol 1998;9:625–630. 7. Martin RE, Ellenbogen KA, Lau YR, Hall JA, Kay GN, Shepard RK, Nixon JV, Wood MA. Phased-array intracardiac echocardiography during pulmonary vein isolation and linear ablation for atrial fibrillation. J Cardiovasc Electro- physiol 2002;13:873–879. Acute and Long-Term Outcome of Transvenous Cryoablation of Midseptal and Parahissian Accessory Pathways in Patients at High Risk of Atrioventricular Block During Radiofrequency Ablation Felipe Atienza, MD, Angel Arenal, MD, Esteban G. Torrecilla, MD, Arcadi Garcı ´a-Alberola, MD, Javier Jime ´nez, MD, Mercedes Ortiz, PhD, Alberto Puchol, MD, and Jesu ´s Almendral, MD The ability of transvenous cryothermal catheter abla- tion to create reversible lesions (cryomapping) and to avoid catheter dislodgment (cryoadherence) has been shown to be safe and highly effective in elimination of atrioventricular nodal reentrant tachycardia. In addi- tion, cryoablation may be useful in the management of perinodal accessory pathways, but its efficacy and safety in patients at high risk of atrioventricular block during radiofrequency catheter ablation is unknown. This study prospectively evaluated the efficacy and safety of cryoablation in patients with midseptal and parahissian accessory pathways. 2004 by Ex- cerpta Medica, Inc. (Am J Cardiol 2004;93:1302–1305) T he ability of transvenous cryothermal catheter ab- lation to create reversible lesions (cryomapping) and to avoid catheter dislodgment (cryoadherence) has shown to be safe and highly effective in eliminating atrioventricular (AV) nodal reentrant tachycardia. 1 In From the Electrophysiology Laboratory, Cardiology Department, Hos- pital General Universitario Gregorio Maran ˜o ´ n, Madrid, Spain. Dr. Arenal’s address is: Laboratorio de Electrofisiologı ´a, Hospital General Universitario Gregorio Maran ˜o ´ n, C/Dr. Esquerdo, 46, 28007 Ma- drid, Spain. E-mail: arenal@doymanet.es. Manuscript received November 19, 2003; revised manuscript received and accepted February 5, 2004. FIGURE 5. Measurements at the level of the common ostium of the left pulmonary veins (A) and systolic peak flow velocity (B). Abbre- viations as in Figures 1 and 4. 1302 ©2004 by Excerpta Medica, Inc. All rights reserved. 0002-9149/04/$–see front matter The American Journal of Cardiology Vol. 93 May 15, 2004 doi:10.1016/j.amjcard.2004.02.020