Shvilkin A.,South Shore Hospital |
Shvilkin A.,Beth Israel Deaconess Medical Center |
Bojovic B.,NewCardio Inc. |
Vajdic B.,NewCardio Inc. |
And 4 more authors.
Heart Rhythm | Year: 2010
Background: There are no established criteria to differentiate new from old left bundle branch block (LBBB). This complicates management of patients with LBBB and suspected acute coronary syndrome. Objectives: The purpose of this study was to develop electrocardiographic (ECG) criteria to differentiate new and old LBBB. Methods: All LBBB tracings (n = 3,706) in a hospital ECG database were retrieved. New (<24 hours, n = 39) and old (>24 hours, n = 1,760) LBBB tracings were identified. QRS and T-wave amplitudes, directions, and durations were measured digitally. Vectorcardiograms were reconstructed from 12-lead ECGs using inverse Dower transform and analyzed with Cardio3KG software. Receiver operator characteristic (ROC) curves were used to develop decision rules to distinguish new and old LBBB. Results: The new LBBB group had larger T-vector magnitude (1.20 ± 0.07 vs. 0.71 ± 0.01 mV), smaller QRS vector magnitude (2.13 ± 0.12 vs. 2.47 ± 0.02 mV), and a lower QRS/T vector magnitude ratio (QRS/T; 1.79 ± 0.03 vs. 3.92 ± 0.04) compared with the old LBBB group (mean ± standard error of the mean, P <.001). The ratio of deepest S to largest T wave in precordial leads (Max S/T) was significantly smaller in the new compared with in the old LBBB group (1.66 ± 0.05 vs. 3.54 ± 0.08; P <.001). A decision rule using QRS/T <2.25 and Max S/T <2.5 had 100% sensitivity and 96%-68% specificity in diagnosing new LBBB, including subsets of patients with tachycardia and ischemia. Conclusions: QRS/T and Max S/T allow accurate discrimination between new and old LBBB suitable for both computerized and manual analysis. If confirmed in prospective studies, this finding can improve management of patients with chest pain and LBBB. © 2010 Heart Rhythm Society.
Kligfield P.,New York Medical College |
Green C.L.,Duke University |
Mortara J.,Mortara Instrument |
Sager P.,Francisco Partners |
And 7 more authors.
American Heart Journal | Year: 2010
This document examines the formation, structure, and principles guiding the use of electrocardiogram (ECG) data sets obtained during thorough QT studies that have been derived from the ECG Warehouse of the Cardiac Safety Research Consortium (CSRC). These principles are designed to preserve the fairness and public interest of access to these data, commensurate with the mission of the CSRC. The data sets comprise anonymized XML formatted digitized ECGs and descriptive variables from placebo and positive control arms of individual studies previously submitted on a proprietary basis to the US Food and Drug Administration by pharmaceutical sponsors. Sponsors permit the release of these studies into the public domain through the CSRC on behalf of the Food and Drug Administration's Critical Path Initiative and public health interest. For algorithm research protocols submitted to and approved by CSRC, unblinded "training" ECG data sets are provided for algorithm development and for initial evaluation, whereas separate blinded "testing" data sets are used for formal algorithm evaluation in cooperation with the CSRC according to methods detailed in this document. © 2010 Mosby, Inc.
Bjerregaard P.,Washington University in St. Louis |
Nallapaneni H.,St Louis University Hospital |
Gussak I.,NewCardio Inc.
Journal of Electrocardiology | Year: 2010
The last ten years have seen a growing interest in clinical scenarios, where a short QT interval may play a role, especially because of an increased risk of sudden cardiac death in some situations. One such entity is Short QT Syndrome, which has emerged as a rare, but very malignant disease, in particular when the QT interval is very short. A short QT interval has also been noticed in some patients with other arrhythmic syndromes such as Idiopathic Ventricular Fibrillation, Brugade Syndrome and Early Repolarization Syndrome, but the role of a short QT interval in these settings is so far not known. Hypercalcemia often leads to shortening of the QT interval, but there are no data in humans to suggest an increased risk of sudden cardiac death in this setting. In addition, a shorterthan-usual QT interval has been reported in patients with Chronic Fatigue Syndrome and in response to atropine, catecholamine and Hyperthermia. When a short QT interval is encountered in daily clinical practice, these various scenarios needs to be considered, but it is still not possible to come up with clear guidelines for how to work up and risk stratify such individuals. Genetic testing is only useful in very few and the value of an electrophysiologic study, Holter monitoring or stress testing to assess QT adaptation to heart rate and T wave morphology analysis may all be helpful, but not well-established, tests in this setting. Published by Elsevier Inc.
Wenzel B.J.,NewCardio Inc.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2011
Acute myocardial infarction (AMI) diagnosis in type II diabetes (DM2) patients is difficult and ECG findings are often non-diagnostic or inconclusive. We developed computer algorithms to process standard 12-lead ECG input data for quantitative 3-dimensional (3D) analysis (my3KGTM), and hypothesized that use of the my3KGTM's array of over 100 3D-based AMI diagnostic markers may improve diagnostic accuracy for AMI in DM2 patients. Methods: We identified 155 consecutive DM2 patients age >25 yrs with chest discomfort or shortness of breath who were evaluated at an urban emergency department (130 patients (pts)) or the cardiac catheterization laboratory (25 pts) for possible AMI. The first digital 12-lead ECG for each patient, obtained within 30 min of presentation, was evaluated by (1) 2 blinded expert cardiologists, and (2) my3KGTM. In each case, the ECG was classified as either likely AMI or likely non-AMI. "Gold standard" was the final clinical diagnosis. Statistical analysis was McNemar's test with continuity correction. Results: The 155 DM2 patients were 50% male, mean age 56.8 ± 12.0 yrs; 44 pts had a final clinical diagnosis of AMI (17 ST Elevation Myocardial Infarctions (STEMI), 27 Non-ST Elevation Myocardial Infarctions (NSTEMI)) and 111 had no AMI. Conclusions: Relative to standard 12L ECG read by cardiologists, quantitative 3D ECG analysis showed significant and substantial gains in sensitivity for AMI diagnosis in DM2 patients, without loss in specificity. Sensitivity gains were particularly high in patients exhibiting NSTEMI, the most common form of AMI in DM2.
NewCardio Inc. | Date: 2011-03-08
Software for use with medical detection and diagnosis devices, namely, in the field of electrocardiography (ECG). Medical devices, in the nature of recording and transmitting devices, namely, wireless, wired, mobile transtelephonic electrocardiography (ECG) monitors for use in acquisition capture and transmission of patient medical data. Maintenance and repair of medical devices. Training in the use of medical devices and software. Installation, maintenance and repair of computer software.