Recommendations for Cardiac Resynchronization Therapy in Patients With Severe Systolic Heart Failure

Class I 
(1) CRT is indicated for patients who have LVEF < 35%, sinus rhythm, LBBB with a QRS duration > 150 msec, and NYHA Class II, III, or ambulatory IV symptoms on GDMT (Guideline Directed Medical Therapy).

Class IIa
(1) CRT can be useful for patients who have LVEF < 35%, sinus rhythm, LBBB with a QRS duration 120-149 msec, and NYHA Class II, III, or ambulatory IV symptoms on GDMT (Guideline Directed Medical Therapy).

(2) CRT can be useful for patients who have LVEF < 35%, sinus rhythm, a non-LBBB pattern with a QRS > 150 msec, and NYHA Class III / ambulatory class IV symptoms on GDMT (Guideline Directed Medical Therapy).

(3) CRT can be useful in patients with atrial fibrillation and LVEF < 35% on Guideline Directed Medical Therapy if (a) the patient requires ventricular pacing or otherwise meets CRT criteria and (b) AV nodal ablation or pharmacologic rate control will allow near 100% ventricular pacing with CRT.

(4) CRT can be useful for patients on GDMT (Guideline Directed Medical Therapy) who have LVEF < 35% and are undergoing new or replacement device placement with anticipated requirement for significant (> 40%) ventricular pacing.


Class IIb
(1) CRT may be considered for patients who have LVEF < 30%, ischemic etiology of heart failure, sinus rhythm, LBBB with a QRS > 150 msec, and NYHA Class I symptoms on GDMT (Guideline Directed Medical Therapy).

(2) CRT may be considered for patients who have LVEF < 35%, sinus rhythm, a non-LBBB pattern with QRS 120-149 msec, and NYHA Class III / ambulatory class IV on GDMT (Guideline Directed Medical Therapy).

(3) CRT may be considered for patients who have LVEF < 35%, sinus rhythm, a non-LBBB pattern with QRS > 150 msec, and NYHA Class II symptoms on GDMT (Guideline Directed Medical Therapy).


Class III
(1) CRT is not recommended for patients with NYHA Class I or II symptoms and non-LBBB pattern with QRS < 150 msec.

(2) CRT is not indicated for patients whose comorbidites and/or frailty limit survival with good functional capacity to less than 1 year.




JACC Vol. 60, No 14, 2012 . October 2, 2012: 1297-1313