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The ECG Lead I Paradox in Cardiac Resynchronization Therapy
Author(s) -
VAN GELDER BERRY M.,
BRACKE FRANK A.
Publication year - 2008
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.2008.01221.x
Subject(s) - medicine , cardiac resynchronization therapy , qrs complex , lead (geology) , cardiology , coronary sinus , basal (medicine) , ventricular pacing , cardiac pacing , heart failure , ejection fraction , geomorphology , insulin , geology
Background: In cardiac resynchronization therapy (CRT), the morphology of the QRS complex plays an important role in the determination of the pacing site and effectiveness of stimulation.Patients and Methods: Review of the electrocardiograms (ECGs) of 737 patients with a CRT device showed a negative QRS complex in lead I during right ventricular (RV) pacing and a positive QRS complex during left ventricular (LV) pacing in four patients. The RV lead was positioned in the high RV septum and the coronary sinus leads in a posterior or postero‐lateral basal level. Reversed ECG lead or pacemaker lead connection, anodal RV stimulation, and scar tissue‐related depolarization abnormalities were excluded as possible causes.Conclusion: Pacing from the high RV septum may rarely lead to a negative QRS complex and basal positions of the LV lead to a positive QRS complex in lead I during LV pacing. The lead I paradox becomes obvious when both phenomena, that are not interrelated, are present in the same patient.