Abstract and Introduction
Abstract
ICD Programming for Shock Reduction
Background Shock therapy delivery by implantable cardioverter-defibrillators (ICD) can be painful and may have adverse consequences. Reducing shock burden for patients with ICDs would be beneficial.
Methods PROVIDE was a prospective, randomized study of primary prevention ICD patients. Patients in the experimental group received a combination of programmed parameters with higher detection rates, longer detection intervals, empiric antitachycardia pacing (ATP), and optimized supraventricular tachycardia (SVT) discriminators, while those in the control group were programmed with conventional parameters. Shock therapy and arrhythmic syncope were compared.
Results Of 1,670 patients enrolled (846 in the experimental group, 824 in the control group) and monitored over a follow-up of 530 ± 241 days, 202 patients received shock therapy for any cause (82 in the experimental group and 120 in the control group). The median time to first shock was significantly prolonged (13.1 vs 7.8 months, hazard ratio [HR]: 0.62, 95% confidence interval [CI]: 0.47 to 0.82, P = 0.0005) and the 2-year shock rate significantly reduced (12.4% vs 19.4%, P < 0.001) in the experimental group compared to the control group. There was no increase in arrhythmic syncope (HR: 1.64, 95% CI: 0.69 to 3.90, P = 0.26), while the overall mortality was reduced (HR: 0.7, 95% CI: 0.50 to 0.98, P = 0.036) in the experimental group compared to the control group.
Conclusion A combination of programmed parameters utilizing higher detection rate, longer detection intervals, empiric ATP, and optimized SVT discriminators reduced ICD therapies without increasing arrhythmic syncope and was associated with reduction in all-cause mortality among ICD patients.
Introduction
Implantable cardioverter-defibrillators (ICD) improve survival in patients with reduced left ventricular systolic function by terminating life-threatening ventricular arrhythmias. Although effective at treating ventricular tachycardia (VT) and ventricular fibrillation (VF), shock therapy can be painful, and repetitive shocks have the potential to impact quality of life and decrease overall survival. As a result, a variety of programming strategies aimed at reducing unnecessary shocks and thereby reducing overall shock burden have been proposed. These approaches, selected from a large array of possible programmable parameters, are designed not only to reduce inappropriate shocks, but also to avoid shocks for nonsustained ventricular arrhythmias.
The Programming Implantable Cardioverter Defibrillators in Patients with Primary Prevention Indication to Prolong Time to First Shock (PROVIDE) study was designed to test the hypothesis that a combination of higher detection rates, prolonged detection intervals, optimized SVT discriminators, and empiric ATP therapy compared to conventional parameters will prolong time to first shock without increasing incidence of arrhythmia-related syncope in patients receiving an ICD for primary prevention of sudden cardiac death.