[Potential risks of the Valsalva maneuver during reciprocating tachycardia in patients with WPW: a case report].

A 42-year-old man with cardiac preexcitation syndrome due to a left postero-septal anomalous pathway, showed an atrio-ventricular reciprocating tachycardia. During a Valsalva manouvre the arrhythmia changed into atrial fibrillation with ventricular rate and consequent hemodynamic worsening. The authors discuss the possible untoward effect of this manouvre in patients with anomalous a-v conduction pathways. They suggest that Valsalva manouvre should not be used outside of the hospital in patients with accessory pathways defined ¿at risk¿ on the basis of the electrophysiologic study.