What are the most common causes of CHF in an adult?

Scenario
C.H. presented to your office with the complaint of a “racing heartbeat.” She is an overweight, 66-year-old African American female, who has been experiencing increasing shortness of breath during the past 4 months and marked swelling of the ankles and feet during the past 3 weeks. She feels very weak and tired most of the time and has recently been waking up in the middle of the night with severe breathing problems. She has been sleeping with several pillows to keep herself propped up. Five years ago, she suffered a transmural (i.e., through the entire thickness of the ventricular wall) anterior wall (i.e., left ventricle) myocardial infarction. She received two-vessel coronary artery bypass surgery 4.5 years ago for obstructions in the left anterior descending and left circumflex coronary arteries. Her family history is positive for atherosclerosis as her father died from a heart attack and her mother had several CVAs. She had been a three-pack-per-day smoker for 30 years but quit smoking after her heart attack. She uses alcohol infrequently. She has a 9-year history of hypercholesterolemia. She is allergic to nuts, shellfish, strawberries, and hydralazine. Her medical history also includes diagnoses of osteoarthritis and gout. Her current medications include celecoxib, allopurinol, atorvastatin, and daily aspirin and clopidogrel.
Questions
Based on the limited amount of information provided above, do you suspect that this patient has developed heart failure based on the most recent guidelines? Explain your answer.
What are the most common causes of CHF in an adult? Given the information in this case, which causes seems to be the most likely?
From the information given above, identify three risk factors that probably contributed to the patient’s heart attack five years ago.
You are curious as to the usefulness of the S3 in making a diagnosis of CHF. You go to the literature and find two studies. The first study started with 100 patients with echocardiographically proven LV systolic dysfunction and an ejection fraction estimated at less than 35%. Of that group, 80 patients had an S3. The other study took 100 normal volunteers and performed auscultation and echocardiography. Of that group, 10 patients with normal echocardiograms had an S3. You then see a patient in your office with a history of exertional dyspnea. You estimate before examining her that she has a “50-50 chance” of having congestive heart failure. If you hear an S3, what do you then think are her chances of having CHF?
What diagnostic tests would you consider in this case?