SHOULD A NEGATIVE ELECTROPHYSIOL0GY STUDY INFLUENCE THE DECISION TO IMPLANT A DEFIBRILLATOR IN PATIENTS PRESENT WITH A CLINICAL VENTRICULAR ARRHYTHMIA?
V. Eipper, D.J. Guy*, G. Tanswell, D.L. Ross.
Department of Cardiology, Westmead Hospital, Sydney, New South Wales.
Electrophysiology studies (EPS) are performed in patients who present with ventricular tachycardia (VT) or ventricular fibrillation (VF) to ensure that an accurate diagnosis, to test the conduction system, to determine the types of arrhythmia inducible, the response to antitachycardia pacing and feasibility for ablation. We examined presenting arrhythmia, EPS result and first recorded event in 161 patients (sustained monomorphic VT (CL>200ms) n = 128, VF n = 33) with implanted defibrillators (ICDs). Mean follow-up was 32+/-24 months. The patients were 60+/-13 years old, 122 with ischaemic heart disease (IHD), 8 with cardiomyopathy, 10 with no structural heart disease (NSD) and 21 with other cardiac abnormalities such as valve disease or congenital heart disease. At EPS (right ventricular pacing, 400ms drive train 4 extras, 3 repetitions) 130 had VT induced, 21 had VF and 10 had no inducible arrhythmia. This final group with no inducible arrhythmia was examined.
Results: EPS was negative in 10 (6%) of the patients. The mean follow-up of this group is 29+/-20 months. Seven of the patients had underlying CAD, 2 presented with VF in a structurally normal heart and 1 had a cardiomyopathy. The presenting arrhythmia was VF in 5 and VT in 5. Of these 10 patients, 3 have had events. Patient 1 (presented with VT, underlying IHD) had VT 3 months post-ICD, patient 2 (presented with VF, NSF) had VF at 3 months post-ICD, patient 3 (presented with VF, underlying IHD) had VT at 5 months post-ICD.
Conclusion: EPS is a worthwhile diagnostic test in patients presenting with VT or VF. Having no arrhythmia induced does not guarantee an event free survival. All patients presenting with sustained ventricular arrhythmias, in the absence of an acute cause, should be considered for ICD implantation.
