Sensitivity For Ventricular Tachycardia Research Articles

ECG spectral and morphological parameters reviewed and updated to detect adult and paediatric life-threatening arrhythmia

Since the International Liaison Committee on Resuscitation approved the use of automated external defibrillators (AEDs) in children, efforts have been made to adapt AED algorithms designed for adult patients to detect paediatric ventricular arrhythmias accurately. In this study, we assess the performance of two spectral (A2 and VFleak) and two morphological parameters (TCI and CM) for the detection of lethal ventricular arrhythmias using an American Heart Association (AHA) compliant database that includes adult and paediatric arrhythmias. Our objective was to evaluate how those parameters can be optimally adjusted to discriminate shockable from nonshockable rhythms in adult and paediatric patients. A total of 1473 records were analysed: 751 from 387 paediatric patients (⩽16 years of age) and 722 records from 381 adult patients. The spectral parameters showed no significant differences (p > 0.01) between the adult and paediatric patients for the shockable records; the differences for nonshockable records however were significant. Still, these parameters maintained the discrimination power when paediatric rhythms were included. A single threshold could be adjusted to obtain sensitivities and specificities above the AHA goals for the complete database. The sensitivities for ventricular fibrillation (VF) and ventricular tachycardia (VT) were 91.1% and 96.6% for VFleak, and 90.3% and 99.3% for A2. The specificities for normal sinus rhythm (NSR) and other nonshockable rhythms were 99.5% and 96.3% for VFleak, and 99.0% and 97.7% for A2. On the other hand, the morphological parameters showed significant differences between the adult and paediatric patients, particularly for the nonshockable records, because of the faster heart rates of the paediatric rhythms. Their performance clearly degraded with paediatric rhythms. Using a single threshold, the sensitivities and specificities were below the AHA goals, particularly VT sensitivity (60.4% for TCI and 65.8% for CM) and the specificity for other nonshockable rhythms (51.7% for TCI and 34.5% for CM). The specificities, particularly for the adult case, improve when the thresholds are independently adjusted for each adult and paediatric database.

An algorithm to discriminate supraventricular from ventricular tachycardia in automated external defibrillators valid for adult and paediatric patients

Aim To adapt adult automated external defibrillator (AED) arrhythmia analysis algorithms for paediatric use through the addition of an algorithm to accurately discriminate supraventricular tachycardia (SVT) from ventricular tachycardia (VT) that is valid for both adult and paediatric patients. Materials and methods An adult database of 89 SVT and 191 VT records from 280 patients and a paediatric database of 322 SVT and 66 VT records from 260 paediatric and adolescent patients were used. The databases were split into two equal groups with respect to numbers of records and patients for development and testing. The discrimination method consisted of a logistic regression classifier based on two features obtained from the spectral analysis of 3.2 s ECG segments of the records. Results The algorithm had an overall accuracy of 98.2% (656/668, one-sided confidence interval (CI) 97.1%). In terms of SVT/VT discrimination, the SVT specificity was 98.1% (403/411, one-sided CI 96.5%), and the VT sensitivity was 98.4% (253/257, one-sided CI 96.5%). In terms of shock/no-shock decisions, the specificity for SVT increased to 99.0% (407/411, one-sided CI 97.8%), 98.8% (318/322, one-sided CI 97.2%) for the paediatric and 100% (89/89, one-sided CI 96.5%) for the adult patients. Conclusion A new algorithm to discriminate SVT/VT was designed that showed high SVT specificity and VT sensitivity in both adults and children. This algorithm could be incorporated into current AEDs with arrhythmia analysis algorithms designed for adult patients to accurately diagnose fast-rate paediatric SVT.

Smart detection algorithm for ICD discrimination between SVT and VT during redetection

Introduction: Dual chamber implantable cardioverter defibrillators (ICDs) can utilize atrio-ventricular timing algorithms to discriminate between ventricular tachycardia (VT) and supraventricular tachycardia (SVT). Most ICDs do not apply discrimination algorithms during redetection following treatment of VT or ventricular fibrillation (VF) but rely instead only on a ventricular rate counter to maintain the highest sensitivity for VT / VF. However, some patients are converted from VT or VF into SVT; others have persistent atrial tachycardia or atrial fibrillation despite conversion of ventricular arrhythmias.

Holter triage ambulatory ECG analysis: Accuracy and time efficiency

Triage ambulatory electrocardiographic (ECG) analysis permits relatively unskilled office workers to submit 24-hour ambulatory ECG Holter tapes to an automatic instrument (model 563, Del Mar Avionics, Irvine, CA) for interpretation. The instrument system “triages” what it is capable of automatically interpreting and rejects those tapes (with high ventricular arrhythmia density) requiring thorough analysis. Nevertheless, a trained cardiovascular technician ultimately edits what is accepted for analysis. This study examined the clinical validity of one manufacturer's triage instrumentation with regard to accuracy and time efficiency for interpreting ventricular arrhythmia. A database of 50 Holter tapes stratified for frequency of ventricular ectopic beats (VEBs) was examined by triage, conventional, and full-disclosure hand-count Holter analysis. Half of the tapes were found to be automatically analyzable by the triage method. Comparison of the VEB accuracy of triage versus conventional analysis using the full-disclosure hand count as the standard showed that triage analysis overall appeared as accurate as conventional Holter analysis but had limitations in detecting ventricular tachycardia (VT) runs. Overall sensitivity, positive predictive accuracy, and false positive rate for the triage ambulatory ECG analysis were 96, 99, and 0.9%, respectively, for isolated VEBs, 92, 93, and 7%, respectively, for ventricular couplets, and 48, 93, and 7%, respectively, for VT. Error in VT detection by triage analysis occurred on a single tape. Of the remaining 11 tapes containing VT runs, accuracy was significantly increased, with a sensitivity of 86%, positive predictive accuracy of 90%, and false positive rate of 10%. Stopwatch-recorded time efficiency was carefully logged during both triage and conventional ambulatory ECG analysis and divided into five time phases: secretarial, machine, analysis, editing, and total time. Triage analysis was significantly ( P < .05) more time efficient for the machine, analysis, and total time phases and required significantly more time in the editing phases. The triage analysis was limited by the inability of the automatic methodology to detect a specific VT waveform contained on one tape. This result which caused substantial loss of sensitivity for VT, emphasizes the necessity for careful quality control and editing of all automatic Holter analysis methods.