Stable" Ventricular Tachycardia Is Not a Benign Rhythm : Insights From the Antiarrhythmics Versus Implantable Defibrillators (AVID) Registry (original) (raw)
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Progress in Cardiovascular Diseases, 1996
The choice of initial therapy for patients with malignant ventricular tachyarrhythmias is examined based on clinical efficacy, patient safety, and cost, Antiarrhythmic drug therapy can be administered using a guided or empiric approach. Guided type-I antiarrhythmic drug therapy has been associated with high arrhythmia recurrence rates (> 40% at 1 year) and moderate sudden death rates {10% at 1 year}. Sotalol is associated with lower arrhythmia recurrence rates (20% at 1 year} that increase to 50% at 4 years. ~-blocking agents have a limited role as stand-alone therapy in this condition. Empiric amiodarone therapy has sudden death-free survival rates of 82% at 2 years but has significantly poorer results in patients with ejection fractions _<40%. In contrast, implantable cardioverter-defibrillator (ICD) therapy has reported sudden death recurrence rates of 1% to 2% per year, with a cumulative index of 10% at 5 years. Total survival rate of ICD recipients ranges from 85% to 92% at 2 years. In patients with good left ventricular function, it approaches 90% at 5 years, whereas it is between 50% to 60% in patients with severe left ventricular dysfunction. Data from device memory indicate an absolute reduction in mortality rates with ICD intervention.
Insights From the Antiarrhythmics Versus Implantable Defibrillators (AVID) Registry
2010
Background—Sustained ventricular tachycardia (VT) can be unstable, can be associated with serious symptoms, or can be stable and relatively free of symptoms. Patients with unstable VT are at high risk for sudden death and are best treated with an implantable defibrillator. The prognosis of patients with stable VT is controversial, and it is unknown whether implantable cardioverter-defibrillator therapy is beneficial.
Failure of an Implantable Cardioverter Defibrillator to Terminate Ventricular Tachycardia: Why?
Pacing and Clinical Electrophysiology, 2010
A 69-year-old man with a history of coronary artery bypass grafting for severe three-vessel coronary artery disease underwent the implantation of a cardioverter defibrillator with cardiac resynchronization (CRT-D) for reduced left ventricular ejection fraction (LVEF) (EF 25%) associated with clinical signs of heart failure (New York Heart Association class III) in December 2005. A three-chamber implantable cardioverter defibrillator (ICD) (Insync Sentry 7298, Medtronic Inc., Minneapolis, MN, USA) was implanted and the improvement of heart failure occurred during the following months despite the development of permanent atrial fibrillation in October 2006. The device was programmed with a ventricular tachycardia (VT) zone of 171-188 beats/min (350-320 ms) and a ventricular fibrillation (VF) zone of 188-500 beats/min (320-120 ms). The counter for VT detection was set at 16 intervals and for VF at 12/16. In the VT zone, the programmed therapy consisted in two antitachycardia pacing protocols (burst and ramp +; three sequences each) followed by cardioversion with 35 J. In the VF zone, therapy consisted of defibrillation at 35 J. Criteria for supraventricular tachycardia discrimination were activated because of persistent atrial fibrillation; pacing mode was VVIR 70-120 beats/min; sequential biventricular pacing was programmed with left ventricular preexcitation of 20 ms. The patient was not taking any antiarryhthmic medication except for β-blockers.
Journal of the American College of Cardiology, 2000
This retrospective study was performed to provide data on ventricular tachycardias (VT) with a cycle length longer than the initially programmed tachycardia detection interval (TDI) in patients with implantable cardioverter defibrillators (ICDs). BACKGROUND It has been clinical practice to program a safety margin of 30 to 60 ms between the slowest spontaneous or inducible VT and the TDI. METHODS Baseline characteristics of 659 consecutive patients with ICDs were prospectively; follow-up information was retrospectively collected. RESULTS During a mean follow-up of 31 Ϯ 23 months, 377 patients (57.2%) had at least one recurrent VT or ventricular fibrillation; 47 patients (7.1%) suffered 61 VTs above the TDI. The risk of a VT above the TDI ranged between 2.7% and 3.5% per year during the first four years after ICD implantation. The difference between the cycle length of the slowest VT before ICD implantation, spontaneous or induced, and the first VT above TDI was 108 Ϯ 58 ms. Fifty-four VTs (88.5%) above the TDI were associated with significant clinical symptoms (angina or palpitation 63.9%, heart failure 6.6% and syncope 8.2%). Six patients (9.8%) had to be resuscitated. Kaplan-Meyer analysis identified New York Heart Association class II or III (p ϭ 0.021), ejection fraction Ͻ 0.40 (p ϭ 0.027), spontaneous (p Ͻ 0.001) or inducible (p Ͻ 0.001) monomorphic VTs and the use of class III antiarrhythmic drugs (amiodarone, p Ͻ 0.001; sotalol, p ϭ 0.004) as risk predictors of VTs above the TDI. The risk of recurrent VTs above TDI was 11.8%, 12.5% and 26.6% during the first, second and third year after first VT above TDI, respectively. CONCLUSIONS The risk of VTs above the TDI is significantly increased in some patients, and many VTs above TDI cause significant clinical symptoms. A larger safety margin between spontaneous or inducible VTs and the TDI seems to be necessary in selected patients. This is in conflict with an increased risk of inadequate episodes and demands highly specific and sensitive detection algorithms in these patients.