J waves are seen in

(Hypothermia) (1319-H) (1389-H17th)ECG-Changes:Hypothermia- Associated with a distinctive convex 'hump' at the J point (Osborn wave)Hypocalcemia- Prolongation of the Q-T interval (ST-segment portion)Hypercalcemia- Abbreviation of the ST segment and shortening of the QT interval.Hypokalemia- Decreased amplitude and broadening of T-wave, prominent U waves, premature ventricular contractions and depressed ST segmentsHyperkalemia- Peaked T waves of increased amplitude, widening of the QRS, and biphasic QRS-T complexes- Severe hyperkalemia causes cardiac arrest with a slow sinusoidal type of mechanism ("sino-wave" pattern) followed by asystole.* "CVA-T-wave" pattern seen in subarachnoid haemorrhage.