Final answer:
Heart failure involves reduced ventricular efficiency due to improper functioning of the endoplasmic reticula in cardiac muscle cells, resulting in inadequate calcium ions for sufficient contraction.
Step-by-step explanation:
The basic pathophysiology of heart failure is best described as a condition where the cardiac muscle cells cannot contract forcefully enough to maintain adequate blood flow to the body's tissues. In heart failure, the endoplasmic reticula of the cells do not function properly, leading to a deficient number of calcium ions for triggering the necessary contractile force. This results in reduced ventricular efficiency, which essentially means the heart is unable to pump with enough force to transport oxygenated blood to all vital organs.