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Cases
Elderly Man With Dizziness
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Background
An 83-year-old man with a history of ischemic congestive heart failure presents with intermittent lightheadedness that has lasted 1 week.
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Scroll
down for Hint and Answer
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***** HINT *****
Review the ECG systematically for rate, rhythm, and axis. Count at least 3 disturbances.
***** ANSWER *****
Bifascicular block with a new onset of atrial
fibrillation: The ECG reveals an irregular
rhythm of 150 beats per minute and no clear P
waves. The QRS complex lasts 128 milliseconds
with an RR' wave in leads V1 and V2 and a wide
S wave in the lateral leads I, V5, and V6. The
axis is deviated to the right.
This patient has severe ischemic heart disease
that produces a bifascicular block with a new
onset of atrial fibrillation (ie, irregular
rhythm with no clear P waves). The right bundle
branch block is associated with a left posterior
hemiblock. This hemiblock is characterized by a
right axis deviation of +120°, small R waves and
deep S waves in lead I, a qR wave in lead III, and
no evidence of other causes of right axis deviation
(eg, lateral myocardial infarction, cor pulmonale,
right ventricular hypertrophy). In the setting of
acute myocardial infarction, this type of block
carries a poor prognosis and mortality rate of 71%.
Reference: Conover MB. Understanding
Electrocardiography. 7th ed. Mosby-Year Book;
1996:362-386.
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Author:
Basmah Safdar, MD
Yale University, Yale New Haven Hospital
eMedicine Editor:
John Leung, MD
Northwestern University, Northwestern Memorial Hospital
Source
http://emedicine.com
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