Diagnosis and Treatment
Figure 2. Indications for Cardiac Resychronization Therapy
Patient with cardiomyopathy on GDMT for ≥3 mo or on
GDMT and ≥40 d after MI, or with implantation of pacing or
defibrillation device for special indications
LVEF ≤35%
Evaluate general
health status
Comorbidities and/
or frailty limit survival
with good functional
capacity to <1 y
Continue
GDMT without
implanted device
Acceptable
noncardiac health
Evaluate NYHA
clinical status
NYHA class I
• LVEF ≤30%
• QRS ≥150 ms
• LBBB pattern
• Ischemic
cardiomyopathy
• QRS ≤150 ms
• Non-LBBB
pattern
NYHA class II
• LVEF ≤35%
• QRS ≥150 ms
• LBBB pattern
• Sinus rhythm
• LVEF ≤35%
• QRS 120-149 ms
• LBBB pattern
• Sinus rhythm
• LVEF ≤35%
• QRS ≥150 ms
• Non-LBBB
pattern
• Sinus rhythm
• QRS ≤150 ms
• Non-LBBB
pattern
NYHA class III
& Ambulatory
class IV
• LVEF ≤35%
• QRS ≥150 ms
• LBBB pattern
• Sinus rhythm
• LVEF ≤35%
• QRS 120-149 ms
• LBBB pattern
• Sinus rhythm
Special CRT
Indications
• Anticipated to
require frequent
ventricular
pacing (>40%)
• AF, if ventricular
pacing is required
and rate control
will result in near
100% ventricular
pacing with CRT
• LVEF ≤35%
• QRS ≥150 ms
• Non-LBBB
pattern
• Sinus rhythm
• LVEF ≤35%
• QRS 120-149 ms
• Non-LBBB
pattern
• Sinus rhythm
Colors correspond to the class of recommendations in the ACCF/AHA Table (pages 18-19).
Benefit for NYHA class I and II patients has been shown in CRT-D trials, and while patients may not experience
immediate symptomatic benefit, late remodeling may be avoided along with long-term HF consequences. There
are no trials that support CRT-pacing (without ICD) in NYHA class I and II patients. Thus, it is anticipated these
patients would receive CRT-D unless clinical reasons or personal wishes make CRT-pacing more appropriate. In
patients who are NYHA class III and ambulatory class IV, CRT-D may be chosen but clinical reasons and personal
wishes may make CRT-pacing appropriate to improve symptoms and quality of life when an ICD is not expected to
produce meaningful benefit to survival.
14
