Long-term outcome of patients with unexplained syncope treated with an electrophysiologic-guided approach in the implantable cardioverter-defibrillator era

OBJECTIVES We evaluated the long-term outcome of patients with coronary art ery disease and unexplained syncope who were treated with an electrophysiol ogic (EP)-guided approach. BACKGROUND Electrophysiologic studies are frequently performed to evaluate unexplained syncope in patients with coronary artery disease. Patients with this profile who have inducible ventricular tachycardia are considered at high risk for sudden death and increased overall mortality, and therefore a re often treated with an implantable cardioverter-defibrillator (ICD). The impact of this EP-guided strategy is unknown because there are no data comp aring the Long-term outcome of ICD recipients with that of noninducible pat ients. METHODS We evaluated 67 consecutive patients with coronary artery disease a nd unexplained syncope. All patients were treated with an EP-guided approac h that included ICD implantation in patients with inducible ventricular tac hycardia. RESULTS Electrophysiologic testing suggested a plausible diagnosis in 32 (4 8%) of these patients. Inducible monomorphic ventricular tachycardia was th e most common abnormality. Despite frequent appropriate therapy with ICDs, the total mortality for patients with inducible monomorphic ventricular tac hycardia was significantly higher than for noninducible patients. The respe ctive one- and tare-year survival rates were 94% and 84% in noninducible pa tients and 77% and 45% in inducible patients (p = 0.02). CONCLUSIONS Electrophysiologic testing suggests an etiology for unexplained syncope in approximately 50% of patients and risk stratifies these patient s with regard to long-term outcome. Patients who receive an ICD for the man agement of inducible ventricular tachycardia have a high incidence of spont aneous ventricular arrhythmias requiring ICD therapy. However, despite ICD implantation and frequent appropriate delivery of ICD therapies, patients w ith inducible ventricular tachycardia have a significantly worse prognosis than do those who are noninducible. (J Am Coll Cardiol 1999;34: 1082-9) (C) 1999 by the American College of Cardiology.