Frequency of toxicity with chemical conversion of atrial fibrillation with dofetilide.

Dofetilide is a class III antiarrhythmic agent approved for the maintenance of sinus rhythm in patients with persistent atrial fibrillation (AF). The goal of this study was to determine if chemical cardioversion (CCV) suggests a greater sensitivity to dofetilide and, therefore, portends a higher risk of proarrhythmia. We analyzed 99 consecutive patients with persistent AF who were loaded on dofetilide before cardioversion. CCV occurred after 2 ± 1.5 doses of dofetilide in 46 patients whereas electrical cardioversion (ECV) was required in the remaining 53 patients after 4.7 ± 1.3 doses. During index hospitalization, there were higher rates of dofetilide discontinuation because of QT prolongation or torsades de pointes (TdP) in the CCV group compared with the ECV group (24% vs 2%, p = 0.001). All patients with CCV requiring drug discontinuation converted after a single dose of dofetilide. Additionally, all 3 patients with TdP were in the CCV group. Furthermore, 15 of the 21 patients with CCV (71%) who converted after the first dose of dofetilide developed significant QT prolongation, requiring dose adjustment or discontinuation of drug. Among patients discharged on drug, AF recurrence and drug discontinuation rates were similar between groups at 2-year follow-up. In patients hospitalized for initiation of dofetilide, CCV occurs in almost 50% and is associated with higher rates of pathologic QT prolongation and TdP compared with those who require ECV. Once discharged on dofetilide, safety and efficacy is similar in both groups. In conclusion, patients with CCV may require closer monitoring for proarrhythmia.

Comparison of the clinical application of the American College of Cardiology Foundation/American Society of Echocardiography Appropriateness Criteria for outpatient transthoracic echocardiography in academic and community practice settings.

BACKGROUND: We sought to compare the clinical application of the American College of Cardiology Foundation/American Society of Echocardiography Appropriateness Criteria (AC) for outpatient transthoracic echocardiography (TTE) in academic and community practice settings. METHODS: Indications for TTE ordered in both academic and community practice settings were determined by 2 reviewers and categorized according to the AC for TTE as Appropriate, Inappropriate, or Not Addressed. Patient characteristics, ordering physician specialty, and TTE findings were also recorded. RESULTS: Overall, 814 academic and 319 community TTEs were analyzed. Interobserver variability for indication determination was high and did not differ between studies ordered at the 2 practice settings. Compared with the academic practice, community practice TTE indications were more likely to be classified in the AC for TTE (88% vs 82%, P = .04), but were ordered for a similar frequency of Appropriate (71% vs 68%, P = not significant) and Inappropriate (17% vs 15%, P = not significant) indications. New important TTE abnormalities were more frequently found in Appropriate studies compared with Inappropriate studies in both academic (35% vs 16%, P < .001) and community practice (29% vs 15%, P = .04) settings. CONCLUSION: The clinical application of the AC for TTE is feasible, and the frequency of Appropriate and Inappropriate outpatient TTEs is similar in academic and community practice settings. However, limitations of the AC for TTE are identified that suggest revisions will be needed to fully encompass and stratify the broad clinical practice of echocardiography.

Usefulness of abnormal heart rate recovery on exercise stress testing to predict high-risk findings on single-photon emission computed tomography myocardial perfusion imaging in men.

Abnormal heart rate recovery (HRR) after maximal exercise treadmill testing predicts adverse cardiac outcomes, although whether abnormal HRR on exercise treadmill testing should prompt further diagnostic cardiac testing is unknown. The aim of this study was to determine the prevalence of high-risk stress single-photon emission computed tomography myocardial perfusion imaging (MPI) findings in patients with abnormal HRR. A total of 509 men who had been referred for exercise stress MPI and were without other abnormal exercise treadmill testing findings (ischemic electrocardiographic changes or exercise treadmill testing-induced angina) were included in this study. Abnormal HRR was defined as a decrease in heart rate or=4, 49% vs 27%; p = 0.001), severe coronary heart disease (SSS >8, 36% vs 7%; p <0.001), left ventricular (LV) dysfunction (LV ejection fraction <50%; 25% vs 6%; p <0.001), and composite high-risk MPI findings (SSS >8 or LV ejection fraction <40%; 40% vs 9%; p <0.001) compared with those without abnormal HRR. On multivariate logistic regression analysis, abnormal HRR was found to be an independent predictor of mild or greater coronary heart disease (odds ratio [OR] 2.4, 95% confidence interval [CI] 1.4 to 4.3, p = 0.003), severe coronary heart disease (OR 5.5, 95% CI 2.7 to 11.0, p <0.001), and composite high-risk MPI findings (OR 4.3, 95% CI 2.1 to 8.6, p <0.001). In conclusion, abnormal HRR on exercise treadmill testing was associated with a high prevalence of abnormal and high-risk stress MPI findings, even in patients without other exercise treadmill testing findings that traditionally would prompt further testing. These findings suggest that further testing with stress MPI should be considered in patients with abnormal HRR on routine exercise treadmill testing.

Prospective evaluation of the clinical application of the American College of Cardiology Foundation/American Society of Echocardiography Appropriateness Criteria for transthoracic echocardiography.

We sought to prospectively evaluate the clinical application of the American College of Cardiology Foundation/American Society of Echocardiography Appropriateness Criteria (AC) for transthoracic echocardiography in a single-center university hospital. Indications for transthoracic echocardiograms (TTE) were prospectively determined for consecutive studies by 2 reviewers and categorized, according to the AC for TTE, as appropriate (A) or inappropriate (I). The overall level of agreement in characterizing appropriateness between reviewers was high (kappa = 0.83). Among the 1,553 studies for which a primary indication was determined, 89% were covered in the AC for TTE. Of these studies, 89% were A, and 11% were I. New important TTE abnormalities were more common on A compared with I studies (40% vs. 17%, p < 0.001), and noncardiac specialists more frequently ordered I studies (13% vs. 9%, p = 0.04). In conclusion, the AC for TTE encompasses the majority of clinical indications for TTE and appears to reasonably stratify TTE ordering. However, revisions will be needed to fully capture and stratify appropriate clinical practice.