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Widening of the QRS Complex During Atrial Pacing: What is the Mechanism?
Author(s) -
MORADY FRED
Publication year - 2002
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1046/j.1540-8167.2002.00627.x
Subject(s) - medicine , citation , qrs complex , cardiology , library science , computer science
An electrophysiologic procedure was performed in a 50-year-old man with a 20-year history of paroxysmal tachycardia. During sinus rhythm, the atrial-His (AH) interval was 70 msec, the His-ventricular (HV) interval was 45 msec, and the QRS width was 80 msec. During atrial pacing at a cycle length of 290 msec, there was widening of the QRS complex (Fig. 1). The transition from a narrow to wide QRS complex is shown at a more rapid paper speed in Figure 2. Upon cessation of pacing, sinus rhythm was present. What accounts for widening of the QRS complex during atrial pacing?