<prompt> Tall T waves are seen in:HyperkalemiaHypocalcemiaHypercalcemiaHypokalemia  <response>: Explanation: ECG changes in Hyperkalaemia Tall T wavesEarliest sign Prolonged PR interval Widened QRS interval Flattened P waves Arrythmias including bradycardia,ventricular tachycardia or fibrillation Sinus arrest or nodal rhythm with possible asystole ECG changesin Hypokalaemia Flattened T waves ST segment depression Prolonged QT interval Tall U waves Atrial arrythmias Ventricular tachycardia or ventricular fibrillation 