Comparison of diagnostic accuracy between three different rules of interpreting high sensitivity troponin T results.

With the introduction of high sensitivity troponin-T (hs-TnT) assay, clinicians face more patients with 'positive' results but without myocardial infarction. Repeated hs-TnT determinations are warranted to improve specificity. The aim of this study was to compare diagnostic accuracy of three different interpretation rules for two hs-TnT results taken 6 h apart. After adjusting for clinical differences, hs-TnT results were recoded according to the three rules. Rule1: hs-TnT >13 ng/L in at least one determination. Rule2: change of >20 % between the two measures. Rule3: change >50 % if baseline hs-TnT 14-53 ng/L and >20 % if baseline >54 ng/L. The sensitivity, specificity and ROC curves were compared. The sensitivity analysis was used to generate post-test probability for any test result. Primary outcome was the evidence of coronary critical stenosis (CCS) on coronary angiography in patients with high-risk chest pain. 183 patients were analyzed (38.3 %) among all patients presenting with chest pain during the study period. CCS was found in 80 (43.7 %) cases. The specificity was 0.62 (0.52-0.71), 0.76 (0.66-0.84) and 0.83 (0.74-0.89) for rules 1, 2 and 3, respectively (P < 0.01). Sensitivity decreased with increasing specificity (P < 0.01). Overall diagnostic accuracy did not differ among the three rules (AUC curves difference P = 0.12). Sensitivity analysis showed a 25 % relative gain in predicting CCS using rule 3 compared to rule 1. Changes between two determinations of hs-TnT 6 h apart effectively improved specificity for CCS presence in high-risk chest pain patients. There was a parallel loss in sensitivity that discouraged any use of such changes as a unique way to interpret the new hs-TnT results.

Efficacy and safety of vernakalant in recent-onset atrial fibrillation after the European medicines agency approval: systematic review and meta-analysis.

Vernakalant is an emergent antiarrhythmic drug that, in preclinical studies, has demonstrated high efficacy in restoring sinus rhythm and safety in patients with rapid recent-onset atrial fibrillation. The aim of this work was to evaluate the efficacy and safety of vernakalant for cardioversion of recent-onset atrial fibrillation. PubMed, EMBASE, Clinical Trials Registry, and European Medicines Agency public reports were searched for randomized clinical trials, until May 2011, of vernakalant compared with controls (placebo/other antiarrhythmic drug) in enrolled patients with high ventricular rate atrial fibrillation. Five randomized trials that met inclusion criteria enrolled a total of 1099 patients. Among these, 810 had recent-onset atrial fibrillation. When compared with controls (placebo/other oral antiarrhythmic drugs), vernakalant was associated with a significant increase in cardioversion within 90 minutes from drug infusion (relative risk, 8.4; 95% confidence interval, 4.4-16.3; P < .00001). Compared with controls, vernakalant was not associated with a significant difference in serious adverse events (relative risk, 0.9; 95% confidence interval, 0.6-1.4; P = .64). The authors conclude that compared with controls, vernakalant is effective and safe for rapidly converting recent-onset atrial fibrillation. Questions remain surrounding safety because 1 unpublished trial was discontinued for this reason. Further cost-effective analysis and comparison with other antiarrhythmic agents, such as class I antiarrhythmic agents, should be investigated, especially in the emergency department.