2010 ECG Changes Hyperkalemia

This figure shows electrocardiogram (or ECG) changes in hyperkalemia. On the left is a vertical line marked from 0 to 16 by increments of 4. The numbers represent milliequivalents per liter. To the right of the 4 marker, the ECG shows a normal rhythm. To the right of the 6 indicator, the ECG shows tenting. The presence of this peaked T wave may be the first indicator of hyperkalemia. As serum potassium rises, the ECG may progressively develop flattened or absent P waves, a prolonged PR interval, widened QRS complex, deepened S waves, and merging of S and T waves. To the right of the 8 marker, the ECG shows the flattening of P waves and a prolonged PR interval, indicative of first-degree heart block. To the right of the 10 indicator, the ECG shows complete heart block. The P wave is flat, and the QRS complex is widened. To the right of the 14 indicator, there is no discernible waveform on the ECG, as occurs with ventricular fibrillation. This figure is copyright 2015 by the American Heart Association.