A 76-year-old woman comes to the office due to intermittent palpitations for the last 6 months. The patient describes episodes of her heart beating fast. These happen on average once a week, last up to an hour, and resolve spontaneously. She cannot identify any provoking factors but thinks they occur typically when she is tired. The patient has had no chest pain, dyspnea, syncope, or lower extremity swelling. She has a history of hypertension. The patient is a lifetime nonsmoker. Blood pressure is 145/85 mm Hg, and pulse is 75/min and regular. There are no heart murmurs. The lungs are clear on auscultation. Peripheral pulses are full and symmetric. ECG shows normal sinus rhythm. Echocardiogram shows moderate left atrial enlargement, left ventricular hypertrophy, ejection fraction of 65%, and no valvular abnormalities. Further workup is most likely to identify which of the following in this patient?

Question

A 76-year-old woman comes to the office due to intermittent palpitations for the last 6 months.  The patient describes episodes of her heart beating fast.  These happen on average once a week, last up to an hour, and resolve spontaneously.  She cannot identify any provoking factors but thinks they occur typically when she is tired.  The patient has had no chest pain, dyspnea, syncope, or lower extremity swelling.  She has a history of hypertension.  The patient is a lifetime nonsmoker.  Blood pressure is 145/85 mm Hg, and pulse is 75/min and regular.  There are no heart murmurs.  The lungs are clear on auscultation.  Peripheral pulses are full and symmetric.  ECG shows normal sinus rhythm.  Echocardiogram shows moderate left atrial enlargement, left ventricular hypertrophy, ejection fraction of 65%, and no valvular abnormalities.  Further workup is most likely to identify which of the following in this patient?

Quizplus · Accepted Answer

11ec25c8_d09f_9998_bc81_c7dbdac336c4_MD0003_00 Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with a prevalence that increases dramatically with age; approximately 70% of those affected are age ≥65. Patients often have episodes of paroxysmal (intermittent) AF in the initial stages and progress to persistent or permanent AF over time. Atrial enlargement and subsequent atrial remodeling likely play an important role in the development of AF, and patients usually have some form of underlying heart disease that contributes to this pathophysiologic mechanism. Hypertension (which can lead to left ventricular hypertrophy) and coronary artery disease (which can lead to ischemic reductions in left ventricular function) can both cause secondary atrial enlargement and are the most commonly associated comorbidities. This elderly patient with hypertension and left ventricular hypertrophy has intermittent palpitations with left atrial enlargement on echocardiogram, suggestive of AF. AF is recognized on ECG by an irregularly irregular rhythm with varying R-R intervals and the absence of P waves. However, due to the intermittent nature of paroxysmal AF, patients can often have a regular pulse with a normal sinus rhythm; therefore, ECG will often fail to make the diagnosis and continuous ambulatory ECG monitoring (eg, for 24 hours) may be needed. ECG (Choice B) Atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) are types of paroxysmal supraventricular tachycardia. These arrhythmias typically present with episodes of palpitations, dyspnea, or presyncope/syncope. They are less common than AF overall and, unlike AF, have a regular rhythm and typically occur in adolescents and young adults. (Choices C and D) Like AF, both second-degree atrioventricular block (with dropped beats) and sinus node dysfunction (sick sinus syndrome, with periods of bradycardia sometimes alternating with tachycardia) increase in prevalence with age. However, these bradyarrhythmias are less likely than AF in this patient with intermittent palpitations, left ventricular hypertrophy, and left atrial enlargement. When symptomatic, they are more likely to cause dyspnea, fatigue, or symptoms of cerebral hypoperfusion (eg, dizziness, lightheadedness, syncope). second-degree atrioventricular block (Choice E) Ventricular tachycardia can present with intermittent palpitations, dizziness, chest discomfort, and presyncope or syncope. It is usually seen in patients with underlying structural heart disease (eg, dilated cardiomyopathy) or previous myocardial infarction. Educational objective: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, and affected patients usually have underlying heart disease (eg, hypertension, coronary artery disease) and left atrial enlargement. The prevalence of AF increases dramatically with age; approximately 70% of those affected are age ≥65. References: Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the anticoagulation and risk factors in atrial fibrillation (ATRIA) study. (http://www.ncbi.nlm.nih.gov/pubmed/11343485) Prevalence, incidence and lifetime risk of atrial fibrillation: the Rotterdam study. (http://www.ncbi.nlm.nih.gov/pubmed/16527828)

A 76-Year-Old Woman Comes to the Office Due to Intermittent