"Supraventricular tachycardia" refers to a rapid heart rate that originates above the ventricles (lower chambers of the heart). It means that the heart beats faster than normal, but the problem lies in the upper part of the heart. Full definition
PhD at the Veterinary College of the University of Turin on «Diagnosis and treatment of supraventricular tachycardia in dogs» (robertosantillimedvet.it)
On 5 March 2010 Dr Roberto Santilli has received the title of Doctor of Philosophy in Veterinary Clinical Sciences at the University of Turin after following a program of three years from 1 November 2005 to 31 October 2008 and had discussed the thesis «Diagnosis and treatment of supraventricular tachycardia in dogs». (robertosantillimedvet.it)
On the extreme side, a common arrhythmia called supraventricular tachycardia can cause fainting or dizzy spells. (health.com)