A 44-year-old man comes to the office for follow-up after a recent hospitalization. The patient went to the emergency department with palpitations 2 weeks ago and was found to have atrial fibrillation with rapid ventricular response. He was admitted to the hospital, where he spontaneously converted to normal sinus rhythm overnight and was discharged home the next day. Prior to this episode, the patient had gone on an alcohol drinking binge during a friend's bachelor party. He otherwise rarely drinks alcohol. Medical history is unremarkable. He is a lifetime nonsmoker. Blood pressure is 124/70 mm Hg and pulse is 78/min and regular. Estimated jugular venous pressure is normal. Examination shows no abnormalities. Review of laboratory results from the hospital admission shows normal creatinine level, liver function tests, thyroid studies, and lipid panel. Echocardiogram shows normal left and right ventricular function and no valvular abnormalities. Which of the following is the best next step in managing this patient?
CHA2DS2-VASc score for thromboembolic risk | |||
Risk criteria | Points | ||
C | Congestive heart failure | 1 | |
H | Hypertension | 1 | |
A2 | Age ≥75* | 2 | |
D | Diabetes mellitus | 1 | |
S2 | Stroke or TIA | 2 | |
V | Vascular disease (eg, PAD, prior MI) | 1 | |
A | Age 65-74* | 1 | |
Sc | Sex category female | 1 | |
Maximum score | 9 | ||
Total score | Generalized stroke risk | Antithrombotic therapy | |
Male | Female** | ||
0 | 0 | Low | None |
1 | 2 | Moderate | None or oral anticoagulant |
≥2 | ≥3 | High | Oral anticoagulant |
*Patients are assigned to 1 of the 2 age categories. **Different cutoffs are used for males & females. Female sex is considered a risk modifier that adds to the CHA2DS2-VASc score only if other nonsex risk factors are present (female patients cannot have a total score of 1). MI = myocardial infarction; PAD = peripheral artery disease; TIA = transient ischemic attack. | |||
This patient had an episode of atrial fibrillation (AF) that spontaneously resolved within 24 hours. The pathophysiology of AF involves aging and comorbidities (eg, hypertension, heart failure) that cause atrial remodeling and create an underlying substrate for AF to develop. The substrate creates a lower threshold for triggers (eg, binge alcohol intake, hyperthyroidism) to initiate and sustain AF; however, sometimes triggers can cause AF in the absence of underlying substrate. After a first episode of AF, patients with risk factors for underlying substrate typically develop recurrent (ie, paroxysmal) or permanent AF.
In contrast, patients without risk factors for underlying substrate (eg, age <50, no significant medical history) are relatively unlikely to experience recurrent AF, especially when the trigger of the episode is removed (eg, cessation of binge alcohol intake, treatment of hyperthyroidism). This is at least part of the reason these patients have low thromboembolic risk associated with AF. They often have a CHA2DS2-Vasc score of 0, as in this patient, for which chronic anticoagulation is not indicated. Men with a CHA2DS2-Vasc score of 1 (or women with a score of 2) also have relatively low thromboembolic risk that may not indicate chronic anticoagulation. In men with a CHA2DS2-Vasc score ≥2 (or women with a score ≥3), chronic anticoagulation is indicated and is accomplished via the administration of a direct oral anticoagulant (eg, rivaroxaban, apixaban, dabigatran) or, less commonly, warfarin (Choices D and E).
(Choice A) Amiodarone is used occasionally for maintenance of sinus rhythm in patients with recurrent, symptomatic episodes of AF (ie, rhythm-control strategy). This patient has spontaneously converted to sinus rhythm, and amiodarone is not indicated. First-line rate control agents (eg, metoprolol) are commonly used but are not needed in patients with relatively low likelihood of recurrent AF.
(Choice B) Dual antiplatelet therapy with aspirin and clopidogrel has shown some benefit in lowering the thromboembolic risk in patients with AF. However, the therapy is rarely used as anticoagulant agents (eg, rivaroxaban, warfarin) provide greater benefit with roughly the same level of increase in bleeding risk.
Educational objective:
Patients without underlying risk factors who develop atrial fibrillation typically have low associated thromboembolic risk. Those with a CHA2DS2-Vasc score of 0 have low thromboembolic risk, and chronic anticoagulation (eg, rivaroxaban) is not indicated.