Background: In patients with mild to moderate left ventricular dysfunction (LVD) (35% £ LVEF
£ 50%) who present with syncope, demonstration of tachy and/or brady-arrhythmia has
prognostic value. In this group of patients electrophysiological study (EPS) is often necessary.
Methods: A total of 53 consecutive patients with mild to moderate LVD and history of
undetermined syncope underwent EPS. Sinus node function, His-Purkinje system conduction
and ventricular electrical stability were evaluated.
Results: Twenty eight patients (52.8%) had induction of sustained monomorphic ventricular
tachycardia (VT) and five (9.4%) patients had a sustained ventricular arrhythmia other than
monomorphic VT (ventricular flutter, ventricular fibrillation, and polymorphic VT) induced
during EPS. Abnormal sinus node function and/or His-Purkinje system conduction was
found in five (9.4%) patients. Age, gender, history of myocardial infarction, type of underlying
heart disease and history of revascularization were not predictors of VT induction. Wide QRS
morphology independently, and lower left ventricular ejection fraction and presence of
pathologic q wave in precordial leads dependently, could increase risk of VT induction.
Conclusions: The EPS can determine which patient with syncope and mild to moderate LVD
is likely to benefit from placing an ICD for prevention of sudden cardiac death. Pathologic
precordial q wave, wide QRS morphology and lower left ventricular ejection fraction could be
predictors of VT induction during EPS. Wide QRS morphology has an independent effect in
this category