High-frequency QRS analysis compared to conventional ST-segment analysis in patients with chest pain and normal ECG referred for exercise tolerance test.

BACKGROUND: The novel analysis of high-frequency QRS components (HFQRS-analysis) has been proposed in patients with chest pain (CP) and normal electrocardiography (ECG) referred for exercise tolerance test (ex-ECG). The aim of the study was to compare the diagnostic value of ex-ECG with ex-HFQRS-analysis. METHODS: Patients with CP and normal ECG, troponin, and echocardiography were considered. All patients underwent ex-ECG for conventional ST-segment-analysis and ex-HFQRS-analysis. A decrease ≥ 50% of the HFQRS signal intensity recorded in at least 2 contiguous leads was considered an index of ischemia, as ST-segment depression ≥ 2 mm or ≥ 1 mm and CP on ex-ECG. Exclusion criteria were: QRS duration ≥ 120 ms and inability to exercise. End-point: The composite of coronary stenosis ≥ 70% or acute coronary syndrome, revascularization, cardiovascular death at 3-month follow-up. RESULTS: Three-hundred thirty-seven patients were enrolled (age 60 ± 15 years). The percent-age of age-adjusted maximal predicted heart rate was 89 ± 10 beat per minute and the maximal systolic blood pressure was 169 ± 23 mm Hg. Nineteen patients achieved the end-point. In multivariate analysis, both ex-ECG and ex-HFQRS were predictors of the end-point. The ex-HFQRS-analysis showed higher sensitivity (63% vs. 26%; p < 0.05), lower specificity (68% vs. 95%; p < 0.001), and comparable negative predictive value (97% vs. 96%; p = 0.502) when compared to ex-ECG-analysis. Receiver operator characteristics analysis showed the incremental diagnostic value of HFQRS (area: 0.655, 95% CI 0.60-0.71) over conventional ex-ECG (0.608, CI 0.55-0.66) and CP score (0.530, CI 0.48-0.59), however without statistical significance in pairwise comparison by C-statistic. CONCLUSIONS: In patients with CP submitted to ex-ECG, the novel ex-HFQRS-analysis shows a valuable incremental diagnostic value over ST-segment-analysis.

Role of masked coronary heart disease in patients with recent-onset atrial fibrillation and troponin elevations.

BACKGROUND: Patients with recent-onset atrial fibrillation (AF) and cardiac troponin I (cTnI) elevations show poor outcomes. Coronary heart disease might be a cause, consequence, or an innocent bystander. OBJECTIVE: The aim of this study was to recognize and treat coronary heart disease to avoid adverse events. METHODS: Patients with recent-onset AF participated in the study. The exclusion criteria were acute coronary syndrome and severe comorbidities. Patients managed with standard care (group 1, n=1086, years 2010-2011) were compared with patients managed with tailored care inclusive of echocardiography and stress testing when required (group 2, n=1055, years 2012-2013). ENDPOINT: The endpoint was a composite of ischemic vascular events including stroke, acute coronary syndrome, revascularization and cardiovascular death at 6 months of follow-up. RESULTS: Of 4008 patients considered, 2141 were enrolled; 183 showed cTnI elevations, 92 in group 1 and 91 in group 2. cTnI elevations, known ischemic heart disease and age were predictors of the endpoint on multivariate analysis. Overall, two versus seven patients (P=0.033) in groups 1 and 2, respectively, underwent revascularization. Eventually, 16 patients in group 1 versus five patients in group 2 reached the endpoint (P=0.019). Patients of group 2 were managed as follow: 35 were admitted, 15 with positive stress testing and 20 with high cTnI values (mean values: 0.64±1.01 ng/ml). Fifty-six patients were discharged with negative stress testing results (n=13) or very low cTnI values (n=43, mean values 0.29±0.30 ng/ml). CONCLUSION: In patients with AF and cTnI elevations, tailored care inclusive of echocardiography and stress testing succeeded in recognizing and treating masked 'critical' coronary heart disease, avoiding adverse events.

Long-term prognostic value of dysglycemia and ischemic vascular disease beyond abnormal troponin levels in patients presenting acute atrial fibrillation.

BACKGROUND: Prognostication beyond troponin levels in patients with acute atrial fibrillation (AF) is still unclear. METHODS: One-month and 1-year outcomes in 1091 patients with acute AF were analyzed. Primary endpoints were stroke or the composite of acute coronary syndrome, revascularization, and death. RESULTS: In the short term, troponin (odds ratio (OR) 15, 95% confidence interval (CI), 3.4-67.9, P < 0.001) and known ischemic heart disease (OR 5.83, 95% CI, 1.3-26.2, P = 0.021) were predictors of the composite endpoint, with multivariate analysis. No variables linked with stroke. In the long term, metabolic syndrome (OR 4.7, 95% CI, 1.2-18.3, P = 0.024) and age (OR 1.1, 95% CI, 1.0-1.1, P = 0.009) were predictors of stroke; metabolic syndrome (OR 4.3, 95% CI, 1.6-11.0, P = 0.003), known ischemic heart disease (OR 3.3, 95% CI, 1.7-6.4, P = 0.001), persistence of AF after the first-line approach (OR 2.2, 95% CI, 1.2-4.3, P = 0.018), and age (OR 1.0, 95% CI, 1.0-1.1, P = 0.025), but not troponin so were of the composite endpoint. In the short term, increased discriminative values in prognostication of the composite endpoint were observed with C-statistic when troponin was compared with dysglycemia (P = 0.032). No variables did better than others in the prognostication of stroke. In the long term, increased discriminative values in the prognostication of stroke were observed with C-statistic when age was compared with troponin (P = 0.020), ischemic heart disease (P = 0.025), and persistence of AF after the first-line approach (P = 0.049); so was for CHADS2 score ≥1 versus vascular disease (P = 0.038). CONCLUSIONS: In patients with acute AF, abnormal troponin levels add prognostic value to clinical parameters in the short term; dysglycemia and known vascular disease in the long term.