Table 6

Diagnostic algorithm for CAN

SymptomsSigns/diagnostic testsDifferential workup
Resting tachycardiaPalpitationsClinical exam: resting heart rate >100 bpm• Anemia
Could be asymptomatic• Hypothyroidism
• Fever
• CVD (atrial fibrillation, flutter, other)
• Dehydration
• Adrenal insufficiency
• Medications
 • Sympathomimetic agents (asthma)
 • Over-the-counter cold agents containing ephedrine or pseudoephedrine
 • Dietary supplements (e.g., ephedra alkaloids)
• Smoking, alcohol, caffeine
• Recreational drugs (cocaine, amphetamines, methamphetamine, mephedrone)
Orthostatic hypotensionLight-headedness Clinical exam: a reduction of >20 mmHg in the systolic blood pressure or >10 mmHg in diastolic blood pressure• Adrenal insufficiency
Weakness• Intravascular volume depletion
Faintness • Blood loss/acute anemia
Visual impairment • Dehydration
Syncope• Pregnancy/postpartum
• CVD
 • Arrhythmias
 • Heart failure
 • Myocarditis
 • Pericarditis
 • Valvular heart disease
• Alcohol
• Medication
 • Antiadrenergics
 • Antianginals
 • Antiarrhythmics
 • Anticholinergics
 • Diuretics
  • ACE inhibitors/angiotensin receptor blocker
  • Narcotics
  • Neuroleptics
  • Sedatives