SUPRAVENTRICULAR TACHYCARDIA

ËÅѡࡳ±ì¡ÒÃÇÔ¹Ô¨©Ñ R-R interval is usually regular (may be irregular in the presence of AV block) QRS rate is usually increased (may be normal or decreased in the presence of AV block) P waves     - most commonly are not visible     - less commonly follow each QRS with a short R-P interval and inverted P wave in leads II, III and AVF ("retrograde" P wave)     - less commonly precede each QRS with a normal PR interval     - least commonly are unrelated to QRS (AV dissociation) ¡ÒÃÇÔ¹Ô¨©ÑÂá¡âä Ventricular tachycardia Sinus tachycardia