CRTs

Class I

•SR, LVEF <-35%, LBBB (QRS>=150ms), NYHA II (B) or III (A), or ambulatory IV (A) symptoms on GDMT

Class IIa

•SR, LVEF <=35%, LBBB (QRS 120-149ms), NYHA II, III or ambulatory IV (A) symptoms on GDMT (B)

•SR, LVEF <=35%, non-LBBB (QRS >=150ms), NYHA III or ambulatory IV (A) symptoms on GDMT (A)

•AF, LVEF <=35%, where pt requires Vp (close to 100%) (B)

•LVEF <=35%, device replacement with >40% Vp (C)

•AV block, pacing indication, EF 36-50%, expected >40% Vp (B)

​

Class IIb

•SR, LVEF <=30%, ICM, LBBB >150ms, NYHA I (C)

•SR, LVEF <=35%, non LBBB (QRS120-149ms), NYHA III/amb III/IV (B)

•SR, LVEF <=35%, non LBBB (>150ms), NYHA II  (B)

•Undergoing surgery (AF, Aov, CAGs, MV) intraoperative placement of an epicardial LV lead (C)

•HF, EF 36-50%, LBBB >150ms (C)

Class III

•NYHA I or II, non LVVV (QRS<150ms) (B)

Survival <1 year