the ability of the pd2i cardiac analyzer to predict risk of ventricular tachyarrhythmic events

Conditions: Tachycardia, Ventricular; Cardiac Sudden Death

Summary: this is a prospective study to evaluating the ability of the pd2i cardiac analyzer to predict the risk of serious heart rhythm abnormalities in high-risk patients that do not already have an implantable cardioverter defibrillator.

the annual incidence of sudden cardiac death in the united states has recently been estimated at 450,000. most of these patients die from ventricular tachyarrhythmias. currently, there is a limited ability to predict reliably which patients are at risk for these events. implantable cardioverter defibrillators (icds) are highly effective at treating the arrhythmias that cause sudden death. multiple clinical trials demonstrating the efficacy of icds for the primary prevention of sudden death have been completed, leading to a relaxation of the selection criteria for their use, and therefore a potentially large expansion in the pool of patients eligible for these devices. this has major economic implications for the health care system, and has led to a need for better prospective identification of patients who are or are not at high risk for sudden death. the existence of beat-to-beat changes in heart rate, termed heart rate variability hrv), has long been recognized by physiologists. however, over the past 15 years, it has been determined that hrv is not a random phenomenon but can be influenced by the brain through the autonomic nervous system. promising work in the analysis of hrv may provide a means of predicting which patients are at risk for sudden death. hrv analysis utilizes mathematical modeling of ecg data to gain insight into the subtle variations in heartbeat patterns which occur from beat-to-beat. the development of a system that could better identify the patients at risk of arrhythmic events would have a significant impact on clinical and economical fields. this study will test software developed by vicor technologies that can potentially identify patients at risk of arrhythmic events. it works as a generic digital-electrocardiogram (ecg) device, as it would normally be used by technical personnel in the routine care of outpatients.

Eligibility criteria:
inclusion criteria: * age \>18 years * left ventricular ejection fraction (lvef) \<35% * prior myocardial infarction * symptomatic congestive heart failure * referred for ep testing and/or prophylactic icd implantation exclusion criteria: * currently has implanted pacemaker or icd * current atrial fibrillation/flutter or atrial fibrillation/flutter requiring cardioversion within the previous 6 months * cardiac surgery or percutaneous revascularization, mi, unstable angina, or cva within the previous 30 days * antiarrhythmic drug therapy other than a beta-blocker within the previous 6 months * previous episode of sustained vt/vf or cardiac arrest, except in the setting of acute myocardial infarction or other reversible cause * life expectancy of less than one year from any non-cardiac cause * expected cardiac transplantation within 6 months

Keywords: ventricular tachycardia cardiac sudden death ventricular fibrillation heart rate variability