Vagal maneuvers (eg, Valsalva maneuver; unilateral carotid massage after exclusion of a carotid bruit, with head tilted to the side opposite the massage, and not for longer than 10 seconds; or applying an ice-cold wet towel to the face) have a success rate of about 25% and are most effective when performed shortly after onset of arrhythmia. Vagal maneuvers can be used in all patients while preparing to administer medications.20
Patients who need treatment can take the “pill-in-the-pocket” approach with single-dose oral flecainide (3 mg/kg) or combined diltiazem and propranolol. Flecainide has a 94% success rate; diltiazem–propranolol has a lower success rate (61%) but a shorter time to conversion to sinus rhythm.21 Patients with sustained or recurrent episodes of SVT should be referred to a cardiologist for chronic prophylactic drug therapy or radiofrequency ablation.
Atrial fibrillation
Hemodynamically unstable patients with AF or atrial flutter, defined by the presence of angina, decompensated heart failure, hypotension, pulmonary edema, or evidence of organ hypoperfusion, should be electrically cardioverted using synchronized direct current.
Hemodynamically stable patients with a rapid ventricular rate should be treated with an IV or oral beta-blocker, CCB, or amiodarone, or electrically cardioverted. IV medications are typically preferred in the acute setting for ease and rapidity of administration; however, there is no evidence that IV formulations of beta-blockers and CCBs are superior to oral formulations. Once the ventricular rate is controlled, patients can be transitioned to an oral short-acting preparation of the selected agent, then converted to an appropriate dosage of an extended-release preparation.22
Cardioversion can be performed in patients with AF < 48 hours. In patients with AF > 48 hours, either 4 weeks of anticoagulation can be given, followed by cardioversion, or transesophageal echocardiography should be performed to evaluate for atrial thrombus; if atrial thrombus is absent, cardioversion can be performed.22 Transesophageal echocardiography might be unnecessary in patients known to have been on sustained anticoagulation.
Rate control is noninferior to rhythm control and does not decrease survival, functional capacity, or quality of life. Rate-control medications include beta-blockers, nondihydropyridine CCBs, amiodarone, and digoxin.
In the AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) trial of 4060 patients, mortality was the same with rhythm control (21.3%) and rate control (23.8%) (HR = 1.15; 95% CI, 0.99-1.34), with no difference in the incidence of cardiac death, arrhythmic death, or death due to stroke.23 In the RACE (RAte Control versus Electrical cardioversion for persistent atrial fibrillation) trial of 522 patients with persistent AF, rate control was noninferior to rhythm control (by cardioversion and drugs) for reducing morbidity and preventing cardiovascular death.24 One possible reason why the rhythm control strategy in the RACE trial did not show superiority is the low number of patients who achieved sustained sinus rhythm.25
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