If all they are documenting is a fib with congestive heart failure nothing else stated then they are considered stable chronic illness which is a moderate. If they state severe exacerbation, it's then considered high risk.
Here is medicare's guidelines for e/m risk factors.
Moderate
• One or more chronic illnesses with
mild exacerbation, progression, or
side effects of treatment
• Two or more stable chronic
illnesses
• Undiagnosed new problem with
uncertain prognosis (lump
in breast)
• Acute illness with systemic
symptoms (pyelonephritis,
pneumonitis, colitis)
• Acute complicated injury
(head injury with brief loss
of consciousness)
• Physiologic tests under stress
(cardiac stress test, fetal
contraction stress test)
• Diagnostic endoscopies with no
identified risk factors
• Deep needle or incisional biopsy
• Cardiovascular imaging studies
with contrast and no identified risk
factors (arteriogram, cardiac
catheterization)
• Obtain fluid from body cavity
(lumbar puncture,
thoracentesis, culdocentesis)
• Minor surgery with
identified risk factors
• Elective major surgery
(open, percutaneous
or endoscopic) with no
identified risk factors
• Prescription drug
management
• Therapeutic nuclear
medicine
• IV fluids with additives
• Closed treatment of
fracture or dislocation
without manipulation
High
• One or more chronic illnesses with
severe exacerbation, progression,
or side effects of treatment
• Acute or chronic illnesses or
injuries that pose a threat to life
or bodily function (multiple
trauma, acute MI, pulmonary
embolus, severe respiratory
distress, progressive severe
rheumatoid arthritis, psychiatric
illness with potential threat to self
or others, peritonitis, acute
renal failure)
• An abrupt change in neurologic
status (seizure, TIA,
weakness, sensory loss)
• Cardiovascular imaging studies
with contrast with identified risk
factors
• Cardiac electrophysiological tests
• Diagnostic Endoscopies with
identified risk factors
• Discography
• Elective major surgery
(open, percutaneous or
endoscopic) with identified
risk factors
• Emergency major surgery
(open, percutaneous or
endoscopic)
• Parenteral controlled
substances
• Drug therapy requiring
intensive monitoring for
toxicity
• Decision not to resuscitate
or to de-escalate care
because of poor prognosis
http://www.cms.gov/Outreach-and-Edu.../Downloads/eval_mgmt_serv_guide-ICN006764.pdf