Ventricular pacemaker with 1:1 retrograde ventriculoatrial (V-A)<unk>  to the atria (arrows).<unk> , also named Ventriculoatrial<unk>  and sometimes referred to as Retrograde<unk> , is the<unk>  backward phenomena in the heart, where the<unk>  comes from the ventricles or from the AV node into and through the atria. Retrograde<unk>  results in many different symptoms, primarily those symptoms result from the delayed, nonphysiologic timing of atrial contraction in relation to ventricular contraction.
VA conduction
QRS complex
Delta wave
Purkinje images
J wave
Plateau potentials
P wave 
Pacemaker current