RT Journal Article SR Electronic T1 Retrograde coronary interventions of chronic total occlusions JF Heart JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP 199 OP 199 DO 10.1136/hrt.2006.091520 VO 93 IS 2 A1 J-Y Moon A1 D Choi A1 Y Jang YR 2007 UL http://heart.bmj.com/content/93/2/199.abstract AB