Discordant effects of carotid sinus massage and intravenous adenosine in atypical (fast-slow) atrioventricular nodal reentrant tachycardia.
The precise mechanism underlying supraventricular tachycardia with a long R-P interval is often difficult to assess noninvasively. Carotid sinus massage has been used traditionally to produce transient AV nodal conduction delay at the bedside, and may be of diagnostic or therapeutic benefit. More recently, adenosine has also been shown to be useful in this situation. We report the case of a patient with an incessant long R-P tachycardia in whom the response to CSM was misleading while the response to adenosine was diagnostic. The electrophysiologic responses to both maneuvers are displayed, and a mechanism for the discordant responses is proposed.
Milchak
M A
MA
Department of Medicine, Dartmouth-Hitchcock Medical Center, Hanover, New Hampshire 03756.
Greenberg
M L
ML
D000241:Adenosine / Q000008:administration & dosage; D000368:Aged; D002346:Carotid Sinus; D004594:Electrophysiology; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008405:Massage; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis / Q000503:physiopathology*; D013617:Tachycardia, Supraventricular / Q000503:physiopathology*
D000241:Adenosine