Catheter Ablation Improves ICDs
The last issue of the New England Journal of Medicine in 2007 includes a report from Harvard researchers about benefits of radiofrequency ablation for a select group of patients with ventricular arrhythmia who had ICDs implanted.
The authors sought to develop an approach to treat patients with ventricular arrhythmia that would better control the incidence of both tachycardia and fibrillation events. That would then reduce the burden on ICDs as means to control disease and the painful side effects. The main outcome of interest in their study was survival free of the occurrence of ICD shocks and pacing.
Study authors recruited 128 patients who had a heart attack from either ventricular fibrillation or tachycardia to receive ICDs, half of the group also underwent radiofrequency catheter ablation. None of the patients were treated with medication for antiarrhythmias. The team noted that substrate-based catheter ablation, an advanced cardiac-mapping system, allows for ablation in this population. Techniques for ablation previously available were not amenable for use in a broad patient set.
Patients who underwent ablation had a decrease in ICD activity (either pacing or shocks) on the order of two-thirds compared to the group that only received device implantation. 31 percent of patients with ICDs only had device discharges compared to nine percent in the group that also had ablation.
Over time, patients who underwent ablation had a 65 percent reduction in ICD discharges compared to the ICD only group. Moreover, there was no significant difference noted in the mortality in the two different treatment groups, though it was nine percent in the ablation group compared to 17 percent in the ICD only group. This finding may become statistically significant in a larger study.
Patients with ventricular arrhythmias are at an increased risk of cardiac death, as indicated in previously published studies. Standard treatment of such includes placement of ICDs. The intent of these devices is to control arrhythmias rather than cure that condition.
One consequence of ICD implantation is device output of electrical discharge, which is painful for patients. This is an unfortunate side effect of a treatment that is necessary to control potentially lethal abnormal changes to rhythms. The addition of ablatio, in a narrowly defined patient population, may prove to be an improved means to control disease.
January 4, 2008 Related topics: Standards, Quality, Safety, Errors, Cardiology