The Role of Electrophysiology Study in Risk Stratification of Sudden Cardiac Death

Patients with ischemic heart disease and left ventricular systolic dysfunction are at high risk of sudden cardiac death. However, most of these high-risk patients will never develop potential fatal ventricular arrhythmias. Thus, modalities that stratify patients according to their risk of sudden cardiac death are needed. The electrophysiology study has, for decades, been used to prognosticate on patients' risk of sudden cardiac death. Recent data from the Multicenter Unsustained Tachycardia Trial (MUSTT) and Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) demonstrate that in patients with ischemic heart disease and left ventricular systolic dysfunction, an electrophysiology study can help identify patients who are at high risk of sudden cardiac death. However, in these patient populations, the prognostic ability of an electrophysiology study is only modest and the negative predictive value is poor. In the future, combining the results of noninvasive modalities with invasive electrophysiology testing may improve our prognostic ability. Furthermore, expanding the role of the electrophysiology study to include therapeutic ablations may alter a patient's future risk of sudden cardiac death.