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New tachycardia study findings have been reported from L.G. Tereshchenko et al
2009 AUG 10 - (NewsRx.com) -- "Arrhythmic sudden cardiac death (SCD) is generally mediated by ventricular fibrillation (VF) or fast ventricular tachycardia (FVT). We studied the predictive value of temporal QT variability detected from various sources of cardiac electric signal: surface ECG, far-field (FF), and near-field (NF) intracardiac electrograms (EGMs) in patients with implantable cardioverter-defibrillators (ICDs)," investigators in the United States report. "Surface ECG and FF and NF intracardiac EGMs were simultaneously recorded at rest (mean heart rate, 74 +/- 15 bpm) for 4.5 +/- 1.3 minutes in 298 patients (mean age, 59 +/- 14; 216 male [73%]) with structural heart disease and an implanted Medtronic ICD for primary (231 patients, 78%) or secondary (67 patients, 22%) prevention of SCD. During mean follow-up of 16 +/- 8 months, 52 (13.1% per person-year of follow-up) patients sustained VTNF and received appropriate ICD therapies, but only 19 (4.8% per person-year of follow-up) patients sustained FVT/VF with cycle length <= 240 ms. The Kaplan-Meier survival analysis showed that the highest QT variability index (QTVI) quartile from all cardiac sources (surface ECG; NF and FF EGMs) is associated with event-free survival (P=0.038 for ECG; P=0.024 for FF EGM; P=0.012 for NF EGM). QTVI was a predictor of all VTNF events and FVT/VF in the multivariate Cox model (including ischemic or nonischemic cardiomyopathy, history of revascularization procedures, LVEF, New York Heart Association class). Strong significant correlation among QTVI determined from all 3 sources was found. -Repolarization lability is present throughout the ventricular myocardium," wrote L.G. Tereshchenko and colleagues. The researchers concluded: "Increased intracardiac QT variability predicts VTNF events in patients with structural heart disease. (Circ Arrhythmia Electrophysiol. 2009;2:276-284.)." Tereshchenko and colleagues published their study in Circulation - Arrhythmia and Electrophysiology (Prediction of Ventricular Tachyarrhythmias by Intracardiac Repolarization Variability Analysis. Circulation - Arrhythmia and Electrophysiology, 2009;2(3):276-284). For additional information, contact L.G. Tereshchenko, Carnegie 592, 600 N Wolfe St., Baltimore, MD 21287, USA. The publisher of the journal Circulation - Arrhythmia and Electrophysiology can be contacted at: Lippincott Williams & Wilkins, 530 Walnut St., Philadelphia, PA 19106-3621, USA. Keywords: United States, Baltimore, Arrhythmia, Cardiology, Defibrillator, Electrophysiology, Heart Arrest, Heart Disease, Intracardiac, Medical Device, Physiology, Sudden Cardiac Death, Tachycardia, Ventricular Fibrillation, Ventricular Tachycardia. This article was prepared by Cardiovascular Week editors from staff and other reports. Copyright 2009, Cardiovascular Week via NewsRx.com.
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