Red Flags in Syncope: Clues for the Diagnosis of Idiopathic Ventricular Fibrillation

  • Bernard Belhassen
    Requests for reprints should be addressed to Bernard Belhassen, MD, Heart Institute, Hadassah Medical Center, Kyriat Hadassah, PO Box 12000, 92210 Jerusalem, Israel.
    Heart Institute, Hadassah Medical Center, Jerusalem and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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  • Oholi Tovia-Brodie
    Jesselson Integrated Heart Center, Shaare Zedek Medical Center, Jerusalem, and Faculty of Health Sciences, Ben Gurion University of the Negev, Beer-Sheva, Israel
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      Idiopathic ventricular fibrillation is responsible for ≈5%-7% of aborted cardiac arrest, mainly striking subjects in their forties. Syncope caused by short-coupled rapid polymorphic ventricular tachycardia is frequently noted in a patient's past history. However, a diagnosis of neurally mediated syncope, the most frequent cause of syncope in the young, is often erroneously made. Clinical clues suggest that syncope has an arrhythmic rather than a neurally mediated origin. In addition, the presence of premature ventricular contractions on an electrocardiogram recorded shortly after a syncopal event has utmost importance in establishing the cause of syncope. Although such extrasystoles are frequently benign, especially when associated with a long coupling interval, they also may suggest a malignant origin when closely coupled to the preceding complex with short coupling intervals (usually <350 ms). These arrhythmias mainly originate from the Purkinje system (usually the right ventricle in men and the left ventricle in women) and favorably respond to quinidine as well as to ablation therapy targeting Purkinje-fibers ectopic activity.


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