<prompt> A 14-year-old boy was brought in a collapsed state with history of 2 episodes of vomiting and had feeble pulse and cold, clammy limbs. ECG is given Figure. What is the diagnosis?HypokalemiaHyperkalemiaHypocalcemiaHypomagnesemia  <response>: Ans: b HyperkalemiaRef: Nelson Textbook of Pediatrics, 20th edition, Page 360ECG shows classical sine wave pattern associated with hyperkalemia.Electrolyte abnormalityECG findingsHypokalemia 2.5 meqLProlonged PR IntervalReduction in T wave amplitude flattening inversion ST depression Appearance of U waveHyperkalemia Mild 5.5 to 6.6 meqLPeaked T waves Prolonged PR segmentModerate 6.5 to 8 meqLLoss of P wave Prolonged QRS complex ST segment elevation Ectopic beast and escape rhythmSevere 8.0 meqLProgressive widening of QRS complex Sine wave Ventricular fibrillation AsystoleHypocalcemiaProlonged QTc segment secondary to lengthening of ST segmentHypomagnesemiaST segment depression Tall, peaked T wavesFlat T waves or depression in the precordiumU wavesLoss of voltagePR prolongationWidened QRS complex 