Arrhythmias with a 1:1 atrial to ventricular ratio could originate from either the atria, the ventricle, or have a component of a reentrant loop within both chambers.
In these cases, it is important to evaluate the timing between the atrial and ventricular signals, the regularity as well as the appearance of the QRS complex. For these rhythms we will first compare the time from the atrial signals to the ventricular signal (AV time) to the time from the ventricular signals to the atrial signals (VA time).
