<prompt> In hyperkalamia-Serum level 5.5 meqLSerum level 6.5 meqlT. wave inversionPeaking of p wave  <response>: Hyperkalemia is defined as a plasma potassium level of 5.5 mM, Early ECG changes of hyperkalemia, typically seen at a serum potassium level of 5.5-6.5 mEqL, include the following: Tall, peaked T waves with a narrow base, best seen in precordial leads Shoened QT interval ST-segment depression At a serum potassium level of 6.5-8.0 mEqL, the ECG typically shows the following: Peaked T waves Prolonged PR interval Decreased or disappearing P wave Widening of the QRS Amplified R wave At a serum potassium level higher than 8.0 mEqL, the ECG shows the following: reference : harrisons principles of internal medicine,19E, page 308,310 Absence of P wave Progressive QRS widening Intraventricularfascicularbundle branch blocks Ref Davidson 23rd edition pg 364 