A 56-year-old man comes to the emergency department due to chest palpitations. He feels that his heartbeat is fast and very irregular. The patient has no chest pain, shortness of breath, or dizziness. Physical examination confirms the presence of an irregularly irregular rhythm with a heart rate of 120/min. He hosted a party last night for his wife's birthday and consumed a large amount of alcohol. The patient normally drinks only 2-3 times a year. He is otherwise healthy and takes no medications. Which of the following ECG findings is most likely in this patient?

Question

A 56-year-old man comes to the emergency department due to chest palpitations.  He feels that his heartbeat is fast and very irregular.  The patient has no chest pain, shortness of breath, or dizziness.  Physical examination confirms the presence of an irregularly irregular rhythm with a heart rate of 120/min.  He hosted a party last night for his wife's birthday and consumed a large amount of alcohol.  The patient normally drinks only 2-3 times a year.  He is otherwise healthy and takes no medications.  Which of the following ECG findings is most likely in this patient?

Quizplus · Accepted Answer

This patient's presentation (palpitations, tachycardia, and irregularly irregular rhythm) is suggestive of atrial fibrillation (AF). The ECG in patients with AF typically shows an absence of P waves and irregularly irregular rhythm with varying R-R intervals. Some patients have irregular, low-amplitude, fine fibrillatory waves (f waves) between the QRS complexes that represent the chaotic atrial activation. AF is the most common tachyarrhythmia and is often precipitated by acute systemic illness or increased sympathetic tone. It is occasionally seen in patients after excessive alcohol consumption ("holiday heart syndrome"). Systemic illnesses that can precipitate AF include long-standing hypertension, heart failure, and hyperthyroidism. (Choice B) High QRS voltage in the precordial leads is a sign of ventricular hypertrophy, which most commonly results from prolonged untreated hypertension. Although hypertension can cause AF, this patient has no history of long-standing hypertension, making his acute binge drinking a more likely etiology. (Choice C) The QRS complexes are narrow in AF. Prolongation of the QRS interval occurs as a result of delay in intraventricular conduction due to fascicular or bundle branch block. The heart rhythm remains regular in patients with intraventricular conduction abnormalities. (Choice D) A prolonged QT interval can be congenital or acquired. It is associated with an increased risk of torsades de pointes (polymorphic ventricular tachycardia) and sudden cardiac death. The QT interval can be prolonged with chronic, heavy alcohol use, but this would be unlikely in a patient who drinks only a few times a year. (Choice E) ST segment elevation on an ECG is typically seen in patients with acute transmural myocardial infarction. In the absence of associated arrhythmias, the heart rhythm is typically regular. Educational objective: Palpitations refer to a subjective sensation/awareness of the heartbeat due to rapid arrhythmias or forceful ventricular contractions. Atrial fibrillation is the most common cause of an irregularly irregular rhythm and is detected on ECG by an absence of organized P waves and varying R-R intervals. __________ References: Long-term alcohol consumption and the risk of atrial fibrillation in the Framingham Study. (http://www.ncbi.nlm.nih.gov/pubmed/15019874)

A 56-Year-Old Man Comes to the Emergency Department Due to Chest