Left ventricular electrical delay can differentiate between ventricular and supraventricular tachycardia in cardiac resynchronization devices Alexander H. Maass, MD, PhD, Hessel F. Groenveld, MD, PhD, Bart A. Mulder, MD, PhD, Michiel Rienstra, MD, PhD, Yuri Blaauw, MD, PhD From the University of Groningen, University Medical Center Groningen, Heart Center, Department of Cardiology, Groningen, The NetherlandsAddress for correspondence: Alexander H. Maass, MD, PhD, University of Groningen, University Medical Center Groningen, Heart Center, Department of Cardiology, P.O. Box 30.001, 9700 RB Groningen, The Netherlands Telephone +31 50 3612355, Fax +31 50 3614391 E-mail: a.h.maass@umcg.nl Disclosures: none Funding: none Keywords: ICD, discriminator, inappropriate therapy, morphology, intracardiac signals.