A 48-year-old man comes to the office for evaluation of palpitations. The patient wakes up frequently at night with a pounding sensation in his chest. He has also experienced "skipped beats" and palpitations during the day on several occasions. He has had no chest pain, dyspnea, lightheadedness, or syncope. The patient lives alone after a recent divorce and says he is afraid that he may die in his sleep. He also states that he feels "stressed out" and has had frequent headaches and feels tired throughout the day. He has smoked a pack of cigarettes daily for the past 20 years and drinks alcohol on the weekends, sometimes excessively.
Blood pressure is 152/89 mm Hg and pulse is 78/min. BMI is 33 kg/m². Heart sounds are normal and the lungs are clear on auscultation. The remainder of the physical examination is within normal limits.
Blood cell counts, serum chemistry studies, and thyroid function tests obtained on a previous visit are within normal limits. ECG shows sinus rhythm with nonspecific T-wave changes, and echocardiography reveals mild left atrial enlargement but is otherwise normal.
Continuous ambulatory ECG (Holter) monitoring is performed for 24 hours and shows frequent premature ventricular contractions, several episodes of bradycardia with heart rates around 30/min between 2 AM and 5 AM, and a 5-second sinus pause followed by a short run of atrial fibrillation at a rate of 130/min at 4:30 AM.
Which of the following is the most appropriate next step in management of this patient?

Question

Quizplus · Accepted Answer

This patient's daytime fatigue, frequent headaches, and systemic hypertension in the setting of obesity suggest underlying obstructive sleep apnea (OSA). Nocturnal cardiac arrhythmias are common in patients with OSA and are likely triggered by hypoxemia as well as alterations in autonomic tone caused by apneic breathing patterns. Bradycardia, sinus pauses, and asystole (defined as pauses >3 seconds), triggered by increases in vagal tone, are the most common arrhythmias observed. Subsequent rebound in sympathetic tone can lead to tachyarrhythmias (eg, nonsustained ventricular tachycardia, atrial fibrillation) that follow the bradycardiac episodes. These tachyarrhythmias, in addition to premature ventricular contractions, may also occur during the daytime. Patients with predominantly nocturnal cardiac symptoms (eg, angina, palpitations) should be evaluated with full-night polysomnography (with ECG to document arrhythmias) to evaluate for underlying OSA. Treatment involves continuous positive airway pressure (CPAP) to suppress arrhythmias and improve mortality. (Choice A) Excessive alcohol intake can worsen OSA (by relaxing pharyngeal musculature) and can also precipitate cardiac arrhythmias (eg, premature ventricular contractions, atrial fibrillation). Although this patient should be counseled on reduction in alcohol intake, OSA is the most likely underlying cause of his nocturnal cardiac symptoms, and obtaining a definitive diagnosis is the most appropriate next step. (Choice B) Exercise stress testing is used to evaluate patients with symptoms suggestive of clinically significant coronary artery disease (eg, exertional angina). This patient's daytime fatigue, frequent headaches, lack of chest pain, and predominantly nocturnal symptoms make OSA more likely. (Choice D) Sick sinus syndrome can cause similar symptoms of bradycardia, sinus pauses, and tachyarrhythmias and is treated with placement of a pacemaker. However, sick sinus syndrome typically occurs in the elderly and causes both daytime and nocturnal symptoms, making OSA more likely in this patient. OSA-mediated sinus pauses and asystole are treated with CPAP and are not typically an indication for placement of a pacemaker. (Choice E) A selective serotonin reuptake inhibitor can treat generalized anxiety, which may cause palpitations. However, this patient's predominantly nocturnal symptoms make OSA more likely. Educational objective: Nocturnal cardiac arrhythmias, including bradycardia, sinus pauses, asystole, and tachyarrhythmias (eg, nonsustained ventricular tachycardia, atrial fibrillation), are common in patients with obstructive sleep apnea (OSA). The diagnosis is made by a full-night polysomnography with ECG monitoring, and continuous positive airway pressure is used to treat OSA and suppress the arrhythmias. __________ References: Role of obstructive sleep apnea in cardiovascular disease (http://www.ncbi.nlm.nih.gov/pubmed/21993356) Obstructive sleep apnea syndrome and cardiovascular diseases (http://www.ncbi.nlm.nih.gov/pubmed/21455862) Triggering of nocturnal arrhythmias by sleep-disordered breathing events. (http://www.ncbi.nlm.nih.gov/pubmed/19874994)

A 48-Year-Old Man Comes to the Office for Evaluation of Palpitations