A 31-year-old woman was brought to the emergency room following an episode of near syncope preceded by palpitations. She was noted to have a wide-complex tachycardia (Figure 1), and was emergently cardioverted. The electrophysiology service was consulted for further management.
Figure 1
Top Image: ECG rhythm strips
Bottom Image: 2 D-Echo - Structurally normal heart with preserved EF.
Past medical history includes severe obesity (body mass index of 50 kg/m2), obstructive sleep apnea, and well-controlled hypertension and type II diabetes mellitus.
Medications:
Lisinopril 10 mg once daily, Gemfibrozil 600 mg twice daily and Metformin 1000 mg twice daily.
Physical Exam: Vital signs: Afebrile, HR 75/min, BP 126/65 mm Hg, RR 14/min
General-Alert, in no acute distress
Neck- No jugular venous distension
Lungs-Clear
Heart-normal
Extremities-no edema, normal pulses
Laboratory Values: (provide ranges)
Normal
Based on the clinical presentation, what is the next best step in this patient’s management?
Show Answer
The correct answer is: C. Electrophysiology study and radiofrequency ablation
Prescribing the appropriate therapy for this patient requires the correct interpretation of the rhythm tracings. The initial tracing shows an irregular (arrows), narrow complex tachycardia, with a rate approaching 300 beats/min, which is consistent with atrial fibrillation (AF). The second tracing shows a regular, wide complex tachycardia, at a rate approaching 300 beats/min. Note the sharp upstroke of the QRS (arrow), which is consistent with conduction over the His-Purkinje system as opposed to ventricular myocardium. The second tracing is consistent with atrial flutter (AFL) with 1:1 atrioventricular (AV) conduction.
Now that the diagnosis is clear, there are several treatment options available to this patient. First, we should note that in the absence of an obvious contributing cause such as pneumonia or pulmonary embolus, AF is likely to recur in this patient. Patients with symptomatic AF are usually treated with a trial of medical therapy,1 consisting of rate- and rhythm-controlling medications. However, the prospect of indefinite treatment with anti-arrhythmic medications in this young patient is not attractive. AV junction ablation and implantation of a permanent pacemaker would definitely prevent rapid rates and hemodynamic compromise; however, it would also result in pacemaker-dependence, which is obviously not desirable in a 31-year-old patient. Given the absence of structural heart disease and ventricular arrhythmias, an implantable cardioverter defibrillator is not indicated. Hence, the most reasonable recommendation is an electrophysiologic evaluation and catheter ablation. The ablation targets should be both the pulmonary veins (PV) and the cavotricuspid isthmus ablation for AF and AFL, respectively. Although the consensus document recommends a trial of medical therapy prior to catheter ablation,1 the dramatic presentation, even though it is the patient's first episode of atrial arrhythmias, in this case calls for a more definitive approach. Also, medical therapy is only modestly effective,2 and may not completely prevent recurrences, which in this patient may again be associated with hemodynamic compromise and syncope.
Our patient underwent PV isolation and linear ablation of the right atrial isthmus without complication. Rapid atrial pacing also reproduced the pattern of aberrancy seen on the presenting tracings (not shown). There was no inducible ventricular tachycardia. Three months after the procedure, the patient remains free of arrhythmias in the absence of antiarrhythmic therapy. She was strongly counseled to lose weight, which may prevent ongoing structural remodeling likely responsible for potentiating AF.3
Reference
Calkins H, Kuck KH, Cappato R, et al. 2012 HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design: a report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation. Heart Rhythm 2012;9:632-696.e21.
Calkins H, Reynolds MR, Spector P, et al. Treatment of atrial fibrillation with antiarrhythmic drugs or radiofrequency ablation: two systematic literature reviews and meta-analyses. Circ Arrhythm Electrophysiol 2009;2:349-361.
Abed HS, Samuel CS, Lau DH, et al.. Obesity results in progressive atrial structural and electrical remodeling: implications for atrial fibrillation. Heart Rhythm 2013;10:90-100.
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