Final answer:
The diagnostic study typically used to confirm heart failure is an echocardiogram, which provides a detailed assessment of the heart's structure and function.
Step-by-step explanation:
The diagnostic study that is usually performed to confirm the diagnosis of heart failure is B. Echocardiogram. An echocardiogram is an ultrasound-based test that allows doctors to visualize the heart in motion, assess the function of its valves and chambers, and measure both the heart's beating strength and the volume of blood passing through it. This test is instrumental in diagnosing heart failure, as it helps cardiologists determine the structural and functional state of the heart. Although an electrocardiogram (ECG) is useful in measuring the heart's electrical activity and can signal heart conditions, it does not provide a direct assessment of the heart's pumping effectiveness, which is crucial for diagnosing heart failure.