Heart rate of a tachycardia is the simplest of all  . . . but   neglected parameter by physicians.  They are often seen spending  hours together for decoding  arrhythmia , splitting their brain for locating P waves ,  VA conduction, Fusion beats etc .Finally  most end up  either administering  Amiodarone a broad spectrum anti arrhythmic agent or a DC shock  without arriving at a correct diagnosis.

Here is an unusual algorithm  for arriving at a diagnosis in all tachy-arrhythmais  based only on heart rate and the width of  the qrs complex with acceptable accuracy.

(Click over the table for high resolution image )