Blood test (CBC, Na, K, BNP, urea, creatinin, AST, ALT, γGT, troponin, blood sugar)
In heart failure BNP is usually > 400 pg/ml. If < 100 pg/ml, consider other diagnosis.
Non invasive test to detect ischemia, coronarography.
Arrhythmia detection (ECG, Holter, ET)
Drugs or alcool consumption.
Medication (chemiotherapy, antidepressive drugs, phenothiazin, anti TNF).