Treatment
Figure 2. Indications for CRT a,b
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
a
b
NYHA Class II
• LVEF ≤35%
• QRS ≥150 ms
• LBBB pattern
• Sinus rhythm
NYHA Class III
& Ambulatory
Class IV
Special CRT
Indications
• Anticipated to
require frequent
ventricular
pacing (>40%)
• LVEF ≤35%
• AF, if ventricular
• QRS 120–149 ms
pacing is required
• LVEF ≤35%
• LBBB pattern
and rate control
• QRS 120–149 ms
• Sinus rhythm
will result in near
• LBBB pattern
100% ventricular
• LVEF ≤35%
• Sinus rhythm
pacing with CRT
• QRS ≥150 ms
• LVEF ≤35%
• Non-LBBB
• QRS ≥150 ms
pattern
• Non-LBBB
• Sinus rhythm
pattern
• QRS ≤150 ms
• Sinus rhythm
• Non-LBBB
• LVEF ≤35%
pattern
• QRS 120-149 ms
• Non-LBBB
pattern
• Sinus rhythm
• LVEF ≤35%
• QRS ≥150 ms
• LBBB pattern
• Sinus rhythm
Colors correspond to colors in the ACCF/AHA classification of recommendations (see pages 54–55).
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.
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