The R-R interval is the same as the P-P interval plus whatever change there is in the PR interval. In typical AV Wenckebach phenomenon, the PR intervals increase with decreasing increments and the R-R ...

This is a narrow complex tachycardia with a rate of 124 beats/min. The QRS morphology and axis are normal. The QTc is prolonged, at 529 ms (normal, 390-450 ms for men). The underlying P waves appear ...