RT Journal Article SR Electronic T1 Fatal Lyme carditis presenting as fluctuating high-grade atrioventricular block JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E574 OP E577 DO 10.1503/cmaj.191194 VO 192 IS 21 A1 Milena Semproni A1 Richard Rusk A1 Terence Wuerz YR 2020 UL http://www.cmaj.ca/content/192/21/E574.abstract