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Ymittos Athens, Greece

Implantable cardioverter-defibrillators (ICDs) are recommended for the primary prevention of sudden cardiac death in patients with left ventricular dysfunction, but it is unclear whether treatment benefits are diminished in patients with very low baseline left ventricular ejection fraction (LVEF) (<25%) or increased in those with prolonged QRS duration (>120 ms). To study the effects of very low LVEF and prolonged QRS duration on the mortality benefits of ICD therapy. We performed a meta-analysis of primary prevention randomized controlled trials comparing ICD and standard medical therapy. All-cause mortality hazard ratios (HRs) in subgroups according to thresholds of 25% for LVEF and 120 ms for QRS duration were extracted from published reports or contributed by trial investigators and synthesized. There was no significant difference of ICD effectiveness in LVEF subgroups of 25%-35% (random effects HR 0.81; 95% confidence interval [CI] 0.70-0.94) vs<25% (HR 0.71; 95% CI 0.55-0.93). Results were also similar in the narrow and wide QRS subgroups (HR 0.78; 95% CI 0.68-0.90 and HR 0.70; 95% CI 0.51-0.95, respectively). Within the LVEF<25% and wide QRS subgroups, there was large heterogeneity driven by the Defibrillator in Acute Myocardial Infarction Trial that included patients with early post-myocardial infarction and its results (HR 1.49; 95% CI 0.84-2.68 and HR 1.51; 95% CI 0.83-2.83, respectively) differed significantly from other trials (P = .008 and P = .01, respectively). LVEF values and QRS duration do not appear to directly modify the survival benefit of ICD in patients with baseline LVEF<35%. However, patients with a recent myocardial infarction do not benefit from ICD, especially when they have LVEF<25% and/or wide QRS. Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved. Source

Katritsis D.G.,Athens Euroclinic | Zareba W.,University of Rochester | Camm A.J.,St Georges, University of London
Journal of the American College of Cardiology | Year: 2012

Nonsustained ventricular tachycardia (NSVT) has been recorded in a wide range of conditions, from apparently healthy individuals to patients with significant heart disease. In the absence of heart disease, the prognostic significance of NSVT is debatable. When detected during exercise, and especially at recovery, NSVT indicates increased cardiovascular mortality within the next decades. In trained athletes, NSVT is considered benign when suppressed by exercise. In patients with non-ST-segment elevation acute coronary syndrome, NSVT occurring beyond 48 h after admission indicates an increased risk of cardiac and sudden death, especially when associated with myocardial ischemia. In acute myocardial infarction, in-hospital NSVT has an adverse prognostic significance when detected beyond the first 13 to 24 h. In patients with prior myocardial infarction treated with reperfusion and beta-blockers, NSVT is not an independent predictor of long-term mortality when other covariates such as left ventricular ejection fraction are taken into account. In patients with hypertrophic cardiomyopathy, and most probably genetic channelopathies, NSVT carries prognostic significance, whereas its independent prognostic ability in ischemic heart failure and dilated cardiomyopathy has not been established. The management of patients with NSVT is aimed at treating the underlying heart disease. © 2012 American College of Cardiology Foundation. Source

Katritsis D.G.,Athens Euroclinic | Siontis G.C.M.,University of Ioannina | Camm A.J.,St Georges, University of London
Progress in Cardiovascular Diseases | Year: 2013

Ventricular arrhythmia can be detected in ambulatory ECG monitoring in individuals with or without cardiac disease, and its prognostic value varies, depending on the underlying condition. The use of continuous or intermittent ambulatory ECG monitoring can be helpful for diagnosis when there is a high pre-test probability of identifying a transient arrhythmia. In addition, Holter monitoring can be used for risk stratification of patients, in the context of the prognostic value of non-sustained ventricular arrhythmias in various clinical settings, as discussed in detail. © 2013 Elsevier Inc. Source

Katritsis D.,Athens Euroclinic | Merchant F.M.,Massachusetts General Hospital | Mela T.,Massachusetts General Hospital | Singh J.P.,Massachusetts General Hospital | And 2 more authors.
Journal of the American College of Cardiology | Year: 2010

Indications for catheter ablation of atrial fibrillation (AF) have expanded to include increasingly complex cases, such as long-standing persistent AF and structural heart disease. Although pulmonary vein isolation remains essential for most ablation procedures, the role of substrate modification has taken on increasing importance. Despite the various ablation strategies available, single-procedure efficacy remains suboptimal among patients with structural heart disease or long-standing persistent AF, where recurrence rates may exceed 50% after a single procedure. These high rates of AF recurrence support the notion that currently available procedural end points are ineffective in identifying which patients are most likely to benefit from substrate modification and defining when that substrate has been sufficiently modified such that additional ablation is unnecessary. In order to improve outcomes, the next generation of procedural end points should seek to define specific properties of the underlying atrial electrical substrate and characterize the impact of catheter ablation on those electrophysiologic properties. The use of substrate-driven end points would be a major step in the process of moving from empiric ablation lesions to a customized ablation strategy based on atrial physiology. In this article, we review current approaches to catheter ablation of AF and discuss specific procedural end points as they pertain to each ablation strategy. We also provide a paradigm for the future development of novel substrate-driven procedural end points. © 2010 American College of Cardiology Foundation. Source

Katritsis D.G.,Athens Euroclinic
Europace | Year: 2010

We report on a patient in whom right-sided ablation at the inferior part of the triangle of Koch was unsuccessful whereas ablation from the left septum was not possible due to ventriculoatrial (VA) block during radiofrequency (RF)-induced junctional rhythm. Successful ablation from the left septum was accomplished only after positioning of a trans-aortic catheter for recording of a left His bundle potential. © The Author 2010. Source

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