RT Journal Article SR Electronic T1 Dual chamber pacing in patients with severe heart failure on β blocker and amiodarone treatment: preliminary results of a randomised study JF Heart JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP 566 OP 567 DO 10.1136/heart.87.6.566 VO 87 IS 6 A1 H Nägele A1 R Schomburg A1 B Petersen A1 W Rödiger YR 2002 UL http://heart.bmj.com/content/87/6/566.abstract AB