Primary prevention of sudden death with implantable defibrillator therapy in patients with cardiac disease - Can we afford to do it? (Can we afford not to?)

The ICD represents an important advance in the prevention of SCD, and there is great temptation to extend the indications for its use beyond what has been demonstrated. Compared with conventional antiarrhythmic drugs or best medical care, the ICD reduces mortality rates in certain patients at risk for SCD, those with ischemic LV dysfunction, and spontaneous18-20 or inducible life-threatening arrhythmias28,30 with the magnitude of benefit related to the severity of LV dysfunction.24,27 However, patients with ischemic LV dysfunction and an abnormal signal-averaged ECG undergoing CABG do not benefit from prophylactic ICD therapy.29 Thus, caution is required in extending the results of past trials to "similar" populations. Although widespread use of ICD therapy for primary prevention of SCD is understandable, this approach is not without risk in terms of complications related to the initial implantation and subsequent revisions, alterations in quality of life and cost. Although it is reasonable and often necessary to extrapolate the findings of past studies, it is prudent to consider a reasonable probability of success, including assessment of SCD risk versus the risk of competing modes of death. Ongoing studies will help to define the role of the ICD for the primary prevention of SCD, and the enrollment of patients in these trials is encouraged. In the absence of a definitive answer, it seems prudent to maximize therapies previously demonstrated to be beneficial in reducing the risk of death and SCD and limit prophylactic ICD use to patients most likely to benefit.