A new algorithm for rhythm discrimination in cardioverter defibrillators based on the initial voltage changes of the ventricular electrogram

Aims: Ventricular activation onset is faster in supraventricular beats than in ventricular rhythms. The aim of this study was to evaluate a criterion to differentiate supraventricular (SVT) from ventricular tachycardia (VT) based on the analysis of the initial voltage changes in ICD-stored morphology electrograms. Methods. Far field ICD-stored EGMs were obtained from 68 VT and 38 SVT episodes in 16 patients. The first EGM peak was detected, three consecutive time epochs were defined within the preceding 80 ms window and the voltage changes with respect to a sinus template were analysed during each time period and combined into a single parameter for rhythm discrimination. Results. The algorithm was tested in an independent validation group of 442 VT and 97 SVT spontaneous episodes obtained from 22 patients with a dual chamber ICD. The area under the receiver-operator characteristics (ROC) curve indicated that the arrhythmia separability with this method was 0.95 (tolerance interval: 0.85-0.99) and 0.98 (0.87-0.99) for the control and validation groups respectively. A specificity of 0.91 was obtained at 95% sensitivity in the validation group. Conclusion. The analysis of voltage changes during the initial ventricular activation process is feasible using the far field stored electrograms of an ICD system and yields a high sensitivity and specificity for arrhythmia discrimination

Long-Term Stroke Risk Prediction in Patients With Atrial Fibrillation:Comparison of the ABC-Stroke and CHA2DS2-VASc Scores

Background The ABC ‐stroke score (age, biomarkers [N‐terminal fragment B‐type natriuretic peptide, high‐sensitivity troponin], and clinical history [prior stroke/transient ischemic attack]) was proposed to predict stroke in atrial fibrillation ( AF ). This score was derived/validated in 2 clinical trial cohorts in which patients with AF were highly selected and carefully followed‐up. However, the median follow‐up was 1.9 years in the trial cohort; therefore, its long‐term predictive performance remains uncertain. This study aimed to compare the long‐term predictive performances of the ABC ‐stroke and CHA 2 DS 2 ‐ VAS c (cardiac failure or dysfunction, hypertension, age ≥75 [doubled], diabetes mellitus, stroke [doubled]—vascular disease, age 65 to 74 years and sex category [female]) scores in a cohort of anticoagulated patients with AF. Methods and Results We recruited 1125 consecutive patients with AF who were stable on vitamin K antagonists and followed‐up for a median of 6.5 years. ABC ‐stroke and CHA 2 DS 2 ‐ VAS c (cardiac failure or dysfunction, hypertension, age ≥75 [doubled], diabetes mellitus, stroke [doubled]—vascular disease, age 65 to 74 years and sex category [female]) scores were calculated and compared. Median CHA 2 DS 2 ‐ VAS c and ABC ‐stroke scores were 4 (interquartile range 3–5) and 9.1 (interquartile range 7.3–11.3), respectively. There were 114 ischemic strokes (1.55% per year) at 6.5 years. The C‐index of ABC ‐stroke at 3.5 years was significantly higher than CHA 2 DS 2 ‐ VAS c (0.663 versus 0.600, P =0.046), but both C‐indexes were nonsignificantly different at 6.5 years. Integrated discrimination improvement showed a small improvement (&lt;2%) in sensitivity at 3.5 and 6.5 years with ABC ‐stroke. For ABC ‐stroke, net reclassification improvement was nonsignificantly different at 3.5 years, and showed a negative reclassification at 6.5 years compared with CHA 2 DS 2 ‐ VAS c. Decision curve analyses did not show a marked improvement in clinical usefulness of the ABC ‐stroke score over the CHA 2 DS 2 ‐ VAS c score. Conclusions In anticoagulated patients with AF followed‐up over a long‐term period, the novel ABC ‐stroke score does not offer significantly better predictive performance compared with the CHA 2 DS 2 ‐ VAS c score. </jats:sec

Does von Willebrand factor improve the predictive ability of current risk stratification scores in patients with atrial fibrillation?

Von Willebrand factor (vWF) is a biomarker of endothelial dysfunction. We investigated its role on prognosis in anticoagulated atrial fibrillation (AF) patients and determined whether its addition to clinical risk stratification schemes improved event-risk prediction. Consecutive outpatients with non-valvular AF were recruited and rates of thrombotic/cardiovascular events, major bleeding and mortality were recorded. The effect of vWF on prognosis was calculated using a Cox regression model. Improvements in predictive accuracy over current scores were determined by calculating the integrated discrimination improvement (IDI), net reclassification improvement (NRI), comparison of receiver-operator characteristic (ROC) curves and Decision Curve Analysis (DCA). 1215 patients (49% males, age 76 (71–81) years) were included. Follow-up was almost 7 years. Significant associations were found between vWF and cardiovascular events, stroke, mortality and bleeding. Based on IDI and NRI, addition of vWF to CHA(2)DS(2)-VASc statistically improved its predictive value, but c-indexes were not significantly different. For major bleeding, the addition of vWF to HAS-BLED improved the c-index but not IDI or NRI. DCA showed minimal net benefit. vWF acts as a simple prognostic biomarker in AF and, whilst its addition to current scores statistically improves prediction for some endpoints, absolute changes and impact on clinical decision-making are marginal

Estimated absolute effects on efficacy and safety outcomes of using non-vitamin K antagonist oral anticoagulants in 'real-world' atrial fibrillation patients:A comparison with optimally acenocoumarol anticoagulated patients

Background Non-vitamin K antagonist oral anticoagulants (NOACs) have been proposed as an alternative to vitamin K antagonists (VKA) for atrial fibrillation (AF) patients. Some studies have proposed that well-managed warfarin therapy is still a valid alternative as efficacious as NOACs but the potential impact and absolute effect of NOACs in “real world” optimally management of VKA AF patients is unknown. Purpose To estimate the potential absolute benefit in clinical outcome rates if the optimally anticoagulated “real-world” AF patients with acenocoumarol had been treated with NOACs. Methods We included 1361 patients stable on acenocoumarol with a time in therapeutic range of 100% for the previous 6 months and 6.5 years of follow-up. The estimation of clinical events avoided was calculated applying absolute risk reductions, relative risk reductions and hazard ratios from the pivotal clinical trials, relative to acenocoumarol. Results Compared to acenocoumarol, the highest estimated event reduction for stroke was seen with dabigatran 150 mg, with an estimated reduction of 0.53%/year. For major bleeding, the highest estimated reduction was seen with apixaban (0.88%/year). For mortality, the largest estimated reduction was with dabigatran 150 mg (0.75%/year). In net clinical outcome, apixaban had the estimated highest reduction (1.23%/year). All NOACs showed significantly lower rates for intracranial haemorrhage. Conclusion In optimally acenocoumarol anticoagulated AF patients, estimated reductions in stroke, bleeding and net clinical outcomes with various NOACs are evident. NOACs would potentially show an improvement even among optimally VKA AF patients

High-Sensitivity Troponin T and Copeptin in Non-ST Acute Coronary Syndromes: Implications for Prognosis and Role of hsTnT and Copeptin in Non-STEACS

High-sensitivity TnT (hsTnT) has been proposed to improve the diagnosis and stratification in acute coronary syndromes. Copeptin has been proposed for a rapid and accurate rule out of acute myocardial infarction, but some doubts exist about its use out of the first hours from admission. Abnormalities of serum hsTnT and copeptin levels in non-STEACS and negative TnT, could have prognostic implications. Methods. We included 122 non-STEACS patients without raised TnT, 33 disease controls and 43 healthy controls. We measured hsTnT and copeptin levels. Clinical follow-up at 12 months was performed for adverse endpoints. Results. Non-STEACS patients had raised hsTnT compared with both control groups (P = 0.036 and P < 0.001). Copeptin levels were higher in non-STEACS patients than healthy controls (P = 0.021), without differences with disease controls. Raised levels of hs-TnT presented prognostic implications [HR 3.29 (95%CI: 1.33–7.49), P = 0.010]. hs-TnT could be used for invasive approach decision, as it shows prognostic relevance in conservative approach-patients whereas remains unrelevant for catheterized-patients. Copeptin levels were not associated with adverse events. Conclusion. hsTnT levels increased in non-STEACS, were predictive of adverse events and could be important for recommending an invasive management. We cannot confirm a predictive role of copeptin out of the first hours from admission