Cardiology 13 - rehellohie

[ArchivalUser]

A 75-year-old woman comes to the office complaining of a 2-day history of palpitations. This morning
her palpitations were accompanied by some lightheadedness and nausea. You have been treating her
for mitral stenosis and hypertension. The patient has no history of coronary artery disease or
arrhythmias, and her exercise stress test from 1 year ago was negative. On physical examination, her
pulse is irregular ranging from 110 to 140/min and her blood pressure is slightly lower than usual at
95/70 mm Hg. A mid-diastolic murmur is audible at the cardiac apex, and her jugular venous pressure
is estimated to be 8 cm H2O. An electrocardiogram demonstrates atrial fibrillation with rapid ventricular
response. You admit the patient to the hospital and she is given a 10 mg bolus of intravenous
metoprolol and her heart slows to 90/min. Another electrocardiogram still demonstrates atrial fibrillation
and her blood pressure is now 135/85 mm Hg. A heparin infusion is started. She is observed overnight
and ruled out for myocardial infarction. After discussing treatment options the patient opts to have
elective cardioversion of her atrial fibrillation. Before she can undergo this procedure, she


A. must have a coronary angiogram

B. must have a negative stress test

C. must have a transesophageal echocardiogram

D. needs digoxin loading for rate control

E. requires anticoagulation for 3 weeks

[ArchivalUser]

eee

[ArchivalUser]

e......

[ArchivalUser]

E. requires anticoagulation for 3 weeks

[ArchivalUser]

E antocoagulation for 3wks

[ArchivalUser]

The correct answer is E. This patient is an elderly female who presented with 2 days of atrial
fibrillation and associated symptoms of lightheadedness and nausea. The etiology of the atrial
fibrillation is stenosis of her mitral valve. Mitral stenosis with elevated left atrial pressures results in left
atrial enlargement, a predisposing factor for the development of atrial fibrillation. Atrial fibrillation, in
the context of mitral stenosis, may compromise proper left ventricular filling due to the lack of an atrial
contraction. This can result in a decreased cardiac output with presenting symptoms of dizziness,
lightheadedness, and even syncope. A rapid ventricular response to atrial fibrillation can decrease
ventricular filling time as well, decreasing cardiac output. Rate control of atrial fibrillation can be
accomplished by beta-blockers, Ca+2 channel blockers, or digoxin. Patients in atrial fibrillation for
>48 hours are at risk for developing atrial thrombi that can embolize. Anticoagulation initially with
heparin is required. Conversion of atrial fibrillation to sinus rhythm can be accomplished by either
electrical or pharmacological methods. In either case, anticoagulation with warfarin is essential before
elective cardioversion can proceed. In emergency cases, if the patient is unstable despite rate
control, cardioversion can be done after assessment of the left atrium for mural thrombus by
transesophageal echocardiogram.

The presence of coronary artery disease is not a contraindication for cardioversion, and the suspicion
of ischemic heart disease is low. A coronary angiogram (choice A) is not required.

Again, the presence of underlying ischemia or coronary artery disease is not a contraindication for
cardioversion. A stress test (choice B) is not required before elective cardioversion.

A transesophageal echocardiogram (choice C) is used to assess the left atrium for mural thrombus
before emergency cardioversion in unstable patients. This patient is stable and undergoing an
elective procedure.

The patient's heart rate appears to be well controlled with beta-blockers and she does not need
digoxin therapy (choice D).