The cause of recurrent syncope is often difficult to determine if the diagnosis is not evident from initial clinical and laboratory investigations.<sup>9 Kapoor W.N., Hammill S.C., Gersh B.J. Diagnosis and natural history of syncope and the role of electrophysiologic testing Am J Cardiol 1989 ;  63 : 730-734  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 10 Kapoor W.N., Karpf M., Weiand S. , e al. A prospective evaluation and follow-up of patients with syncope N Engl J Med 1983 ;  309 : 197-204  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 16 Morady F., Shen E., Schwartz A. , e al. Long term follow-up of patients with recurrent unexplained syncope evaluated by electrophysiologic testing J Am Coll Cardiol 1983 ;  2 : 1053-1059  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 20 Sra J.S., Anderson A.J., Sheikh S.H. , e al. Unexplained syncope evaluated by electrophysiologic studies and head-up tilt testing Ann Intern Med 1991 ;  114 : 1013-1019

Cliccare qui per andare alla sezione Riferimenti</sup> A cause is not determined after a standardized diagnostic evaluation in 38% to 47% of patients.<sup>4 Day S.C., Cook E.F., Funkenstein H. , e al. Evaluation and outcome of emergency room patients with transient loss of consciousness Am J Med 1982 ;  73 : 15-23  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 8 Kapoor W.N. Evaluation and outcome of patients with syncope Medicine 1990 ;  69 : 160-175

Cliccare qui per andare alla sezione Riferimenti, 10 Kapoor W.N., Karpf M., Weiand S. , e al. A prospective evaluation and follow-up of patients with syncope N Engl J Med 1983 ;  309 : 197-204  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 15 Martin G.J., Adams S.L., Martin H.G. , e al. Prospective evaluation of syncope Ann Emerg Med 1984 ;  13 : 499-504  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Although patients with negative investigations for syncope are said to have a good prognosis,<sup>2 Bass E.B., Elson J.J., Fogors R.N. , e al. Long-term prognosis of patients undergoing electrophysiologic studies for syncope of unknown origin Am J Cardiol 1988 ;  62 : 1186-1191  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 6 Denniss A.R., Ross D.L., Richards D.A. , e al. Electrophysiologic studies in patients with unexplained syncope Int J Cardiol 1992 ;  35 : 211-217

Cliccare qui per andare alla sezione Riferimenti, 7 Doherty J.U., Pembrook-Rogers D., Grogan E.W. , e al. Electrophysiologic evaluation and follow-up characteristics of patients with recurrent unexplained syncope and presyncope Am J Cardiol 1985 ;  55 : 703-708  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 13 Kushner J.A., Kou W.H., Kadish A.H. , e al. Natural history of patients with unexplained syncope and a nondiagnostic electrophysiologic study J Am Coll Cardiol 1989 ;  14 : 391-396  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> they continue to suffer from recurrent syncope (19% to 43% over an 18- to 36-month follow-up period) with significant morbidity and a small risk of arrhythmic death.<sup>2 Bass E.B., Elson J.J., Fogors R.N. , e al. Long-term prognosis of patients undergoing electrophysiologic studies for syncope of unknown origin Am J Cardiol 1988 ;  62 : 1186-1191  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 6 Denniss A.R., Ross D.L., Richards D.A. , e al. Electrophysiologic studies in patients with unexplained syncope Int J Cardiol 1992 ;  35 : 211-217

Cliccare qui per andare alla sezione Riferimenti, 7 Doherty J.U., Pembrook-Rogers D., Grogan E.W. , e al. Electrophysiologic evaluation and follow-up characteristics of patients with recurrent unexplained syncope and presyncope Am J Cardiol 1985 ;  55 : 703-708  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 13 Kushner J.A., Kou W.H., Kadish A.H. , e al. Natural history of patients with unexplained syncope and a nondiagnostic electrophysiologic study J Am Coll Cardiol 1989 ;  14 : 391-396  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 17 Muller T., Roy D., Talajic M. , e al. Electrophysiologic evaluation and outcome of patients with syncope of unknown origin Eur Heart J 1991 ;  12 : 139-143

Cliccare qui per andare alla sezione Riferimenti, 20 Sra J.S., Anderson A.J., Sheikh S.H. , e al. Unexplained syncope evaluated by electrophysiologic studies and head-up tilt testing Ann Intern Med 1991 ;  114 : 1013-1019

Cliccare qui per andare alla sezione Riferimenti</sup> Many of these patients are unable to drive and can suffer serious injuries associated with recurrent syncope. Little is known regarding the cause of syncope in patients with negative investigations who continue to lose consciousness.