<unk>  <unk> V) refers to the physiological phenomenon of beat-to-beat fluctuations in<unk><unk>  of electrocardiograms. Increased<unk> V appears to be a marker of arrhythmic and cardiovascular death; it may also play a role for noninvasive assessment of sympathetic nervous system activity. Other terms used include: "QT<unk> ", "beat-to-beat<unk>  of ventricular repolarization (BRV)" Beat-to-beat measurement of<unk><unk>  using two-dimensional signal warping (2DSW).
QT interval variability
Junctional rhythm
T wave alternans
Pacemaker current
High frequency QRS
VA conduction
Heart rate variability
Instantaneous wave-free ratio