Final answer:
The myocardium of the left ventricle is most commonly affected with congestive heart failure (CHF).
Step-by-step explanation:
The myocardium of the left ventricle is most commonly affected with congestive heart failure (CHF). CHF is a condition in which the heart is unable to pump enough blood to meet the body's needs. The left ventricle is responsible for pumping oxygenated blood to the rest of the body through the systemic circuit.