In This Edition:
- Catheter ablation for atrial fibrillation
- Noncontrast CT for appendicitis diagnosis
- Effectiveness of whole-leg ultrasound for DVT diagnosis
- Physician localization and nurse-physician communication
- PPI versus H2 blocker in patients with aspirin-related peptic ulcer disease
- Intensive insulin therapy in steroid-induced hyperglycemia associated with septic shock
- S. aureus decolonization and surgical-site infections
- ABCD2 score and risk of subsequent stroke
Clinical question: In patients with paroxysmal atrial fibrillation (AF) unresponsive to initial antiarrhythmic therapy, what is the efficacy of catheter ablation compared with continued attempts at rhythm control?
Background: Although antiarrhythmic drug therapy (ADT) is generally first-line AF therapy, AF recurrence is high and treatment is associated with adverse effects. Catheter ablation is an alternative treatment. Recent studies comparing antiarrhythmic drugs and catheter ablation have involved small populations and have shown mixed results.
Study design: Prospective, multicenter, unblinded, randomized trial.
Setting: Nineteen hospitals—15 in the U.S.—with considerable experience in AF ablation.
Synopsis: This trial compared catheter ablation (n=106) vs. ADT (n=61) for symptomatic, paroxysmal AF refractory to at least one antiarrhythmic drug. Patients in the ablation arm were allowed up to three procedures within an 80-day period; patients in the ADT arm were treated with a previously unused class I or class III antiarrhythmic. After nine months, 34% of ablated patients had failed treatment compared with 84% of patients receiving ADT (HR 0.30 [95% CI, 0.19-0.47]).
While the results are encouraging, some limitations should be noted. Attempts to generalize the results of this study might be limited, as the hospitals had considerable experience in AF ablation, the patient population was relatively young (mean age=56 years), and patients with significant left ventrical dysfunction and persistent AF were excluded.
Furthermore, the long-term effectiveness of ablation was not evaluated, and the study did not assess such outcomes as mortality, stroke, or AF progression. The effectiveness of specific ablation techniques could not be determined because a variety of approaches was employed.
Bottom line: Patients with symptomatic paroxysmal AF without advanced heart failure might benefit from catheter ablation at experienced institutions.
Citation: Wilber DJ, Pappone C, Neuzil P, et al. Comparison of antiarrhythmic drug therapy and radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation: a randomized controlled trial. JAMA. 2010;303(4):333-340.
Clinical question: What is the diagnostic accuracy of noncontrast helical CT in the evaluation of suspected acute appendicitis in the ED?
Background: In the workup of acute appendicitis, various CT protocols are used, including combinations of oral, intravenous, and rectal contrast, as well as noncontrast protocols. Noncontrast CT is less time-consuming and avoids risk of allergic reaction or contrast-induced nephropathy. The diagnostic accuracy of noncontrast CT, however, is controversial.
Study design: Systematic review/meta-analysis.
Setting: Seven studies evaluating acute appendicitis with noncontrast CT in ED settings.
Synopsis: This is the first systematic review of noncontrast CT (helical/multislice) in adults with suspected appendicitis. The authors pooled seven studies (1,060 patients) comparing noncontrast CT with a reference standard of final diagnosis at surgery or followup at a minimum of two weeks. The review yielded the following pooled estimates: sensitivity 93%, specificity 96%, positive likelihood ratio 24, and negative likelihood ratio 0.08. Overall, the diagnostic accuracy of noncontrast CT was high.
A few limitations should be noted. In the original studies, results were reported inconsistently. In one study, 24% of scans were inconclusive, with an associated likelihood ratio of approximately 1. Future studies must address this important clinical question of how to treat patients with inconclusive scans. Another question is to what degree the accuracy reported in this study reflects the expertise of the institutions, the majority of which were university-affiliated. According to one study author, “a certain level of experience is required for skillful interpretation” of noncontrast CT.