“Quinidine Syncope” without Lengthening of Q-Tc Interval in the Presence of Left Bundle Branch Block

Idiosyncratic and proarrhythmic reactions to antiarrhythmic drugs are a well-recognized phenomenon and appear to correlate poorly with Q-T prolongation or with the serum concentration of the drug. It therefore becomes difficult to identify patients clinically with an underlying electrophysiologic su...

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Veröffentlicht in:Chest 1988-07, Vol.94 (1), p.111-114
Hauptverfasser: Fields, Constance D., Ezri, Marilyn D., Denes, Pablo
Format: Artikel
Sprache:eng
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Zusammenfassung:Idiosyncratic and proarrhythmic reactions to antiarrhythmic drugs are a well-recognized phenomenon and appear to correlate poorly with Q-T prolongation or with the serum concentration of the drug. It therefore becomes difficult to identify patients clinically with an underlying electrophysiologic substrate for ventricular tachycardia which was made manifest by an antiarrhythmic drug, or to determine whether the drug is causing an idiosyncratic reaction (the classic “long Q-T syndrome”). We recently studied a patient with ischemic heart disease and a prolonged corrected Q-T interval (Q-Tc) due to chronic left bundle-branch block. She developed “quinidine syncope,” and the Q-Tc was unchanged despite stopping administration of the drug; however, electrophysiologic studies demonstrated reproducibly inducible “torsade de pointes” while the patient was being rechallenged with quinidine, while no inducible arrhythmia was seen during control studies. We conclude that electrophysiologic studies are of clinical value in the clarification of possible drug-induced arrhythmias.
ISSN:0012-3692
1931-3543
DOI:10.1378/chest.94.1.111