Ventricular tachycardia (VT) refers to runs of more than 3 VPCs in sequence. As above for VPCs, QRS complexes are wide and bizarre, and there is lack of association with P waves (A-V dissociation). VT may markedly reduce cardiac output (through dyssynergy of contraction and high heart rate). Etiology is as for premature ventricular contractions (see above). VT is treated as described above under premature ventricular contractions. Again, the presence of clinical signs, the presence of an underlying heart disease known to be associated with sudden death, and high heart rate are likely the most important criteria for treatment. Slow VT (VT rate from 80 – 140 bpm in dogs) frequently has minimal hemodynamic consequences and therefore warrants observation but not necessarily anti-arrhythmic therapy.