50，000 per year of life saved). It is current status that ICD is the only effective way in prevention of SCD. Catheter ablation of ventricular arrhythmias is useful in a small number of highly selected patients.

    None of the currently available antiarrhythmic drugs has been proved to be useful for prevention of SCD. In turn， many antiarrhythmics (particularly class Ic drugs) may increase rather than decrease mortality rate. Class III antiarrhythmics including amiodarone do not reduce mortality rate and cannot be used to replace ICD for prevention of SCD. Interestingly， several drugs without significant direct electrophysiologic actions on myocardial excitable tissue， such as beta-blocker， angiotensin converting enzyme inhibitor， lipid-lowering agent， thrombolytic and antithrombotic agent， spironolactone， and magnesium， may decrease total mortality rate， including SCD rate. These pharmacologic and non-pharmacologic treatments may be used in conjunction with ICD therapy but cannot be used to replace its role in either primary or secondary prevention of SCD. Above all， risk stratification for SCD still remains one of the major challenges confronting every clinician.