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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:
Glucose 186 mg/dL
Na 128 mg/dL
K 5.8 mEq/L
t bilirubin 3.8 mg/dL
albumin 3.8 g/dL
alkaline 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 decompensation A.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 remodeling and
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 lb instead 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.