Chapter 20, Heart Failure

Case Study/Short-Answer Questions and Discussion Points

A.J. is a 64-year-old farmer who had a septal myocardial infarction (MI) 4 years ago and has had chronic heart failure since then. His ejection fraction is 36%, and on his current medical regimen, he is considered in a New York Heart Association class II. In his compensated state, he is able to continue farming, care for his cows and chickens, and meet his responsibilities without problem, although he has slowed his pace since the MI. In the interim, he has developed type 2 diabetes which is well controlled with glypizide 5 mg twice a day by mouth. His most recent HbgA1c was 5.8%. Over the last 3 weeks, he has begun to get fatigued more easily with the same amount of effort. He notes that his ankles are swollen and have not gone down over night as they usually do and that his abdomen has increased in size to the point he cannot fasten his trousers. Last night he was unable to lie down in bed because he could not breathe; he slept in his recliner. His wife insisted that he see his cardiologist today. A.J.’s ECG demonstrated a new inferior MI and a left bundle branch block with a QRS duration of 162 milliseconds. He is admitted to the Coronary Care Unit for a diagnostic evaluation including cardiac catheterization and treatment for his acute decompensated heart failure (ADHF). A.J. does not weigh himself regularly at home and he was surprised to find his weight had increased 43 pounds since his last physician visit 4 weeks ago. His physical examination was significant for a new mitral regurgitation murmur (II/VI), an S3, jugular venous distention to his earlobe, and ascites. He did not have crackles or decreased breath sounds.

Vital signs are blood pressure 88/46, pulse rate 76, respiratory rate 28, and temperature 98.8°F.

The cardiac catheterization demonstrated a mid-right coronary artery occlusion of 95%, which was treated with a drug-eluting stent. His cardiac index after the stent placement was 3.1 L/min/m2. Furthermore, his cardiologist ordered a new echocardiogram that demonstrated a decrease in his ejection fraction to 26% with ventricular dysynchrony. He will also receive an implantable cardioverter–defibrillator with a biventricular pacemaker during this hospitalization.

His significant laboratory values on admission were:

Glucose186 mg/dLt bilirubin3.8 mg/dL

Na 128 mg/dLalbumin3.8 g/dL

K5.8 mEq/Lalkaline phosphatase 160 Units/L

BUN 68 mg/dL

Creatinine 2.1 mg/dL

1. Silent MIs are common in patients with diabetes.What effect did having a new MI have on the increase in symptoms and decompensationA.J. experienced?

“Silent” MIs are common in patients with diabetes.He had typical symptoms of radiating, substernal chest pain; he might have sought help sooner.Because he did not have symptoms, he lost heart muscle that cannot be recovered and that leads to decreased ejection fraction (EF), decreased pumping ability, activation of the renin-angiotensin system, and fluid overload.

2. A.J. has ventricular dysynchrony.How will having a biventricular pacemaker improve his symptoms?

A.J. has ventricular dysynchrony.He was already on optimal medication for his heart failure and, prior to the new MI, was doing well.The remodelingand enlargement of his left ventricle changed the conduction time of impulses traveling through the septum and around the right and left ventricles.Consequently, the longer travel time around the left ventricle delayed the contraction so that the normal synchronization of left and right ventricles was disturbed leading to a decreased cardiac output.The biventricular pacer is timed to cause both of the ventricles to contract together improving cardiac output.

3. What specific things can A.J. do to decrease the likelihood that he will be surprised by a large weight gain associated with ADHF?

To avoid a surprisingly large weight gain, A.J. can adhere to a low-sodium diet, weigh himself daily and record his weight, take his medication regularly, and call his cardiologist when his weight changes by 3 to 5 lbinstead of waiting until the water weight gain increases his symptoms.Even though A.J. does all the right things, he may still develop ADHF because of factors he can’t control.