Aims and Objective:
To study the correlation of ECG changes in hypokalemic periodic palsy with serum potassium level.
Material and Method:
Thirty five cases of clinically diagnosed hypokalemic periodic palsy were included in this study admitted to medicine wards of VSS Medical College Hospital, Burla during the period of February 2004 to June 2004. Correlation between electrocardiographic changes i.e PR – interval , QRS – duration, QTc – interval, ST- Segment depression, flattening of T-wave and presence of U-wave and AV block with corresponding serum potassium level was studied.

Secondary causes of hypokalemia were excluded in this study.

Observation:
ECG Changes of 35 cases are tabulated below with serum potassium level
Se. K+ level in mEq/L Total Cases Prolonged PR interval Presence of U-wave
Mild (3.1 – 3.5) 1 0 1
Moderate (2.6-3) 14 1 14
Severe (<2.5) 20 05 20

There were one (2.9%) cases of mild, 14(40%) cases of moderate and 20(57.1%) cases of severe hypokalemia. At the time of admission all 35 (100%) cases showed flattering of T-wave with presence of U-wave in ECG and prolonged QTc – interval in 32(91.4%) cases. ST –depression was found only 20 (57.1%) cases. Out of 10 cases of AV – block, 6(17.1%) cases had first degree AV-block with prolonged PR interval and 4(11.4%) cases had second degree AV – block.

Out of 10 cases of AV- block 9 (90%) cases had AV-block with serum potassium level 2.5 mEq/L and 1(10%) case had AV block with serum potassium 2.8 mEq/L.

Conclusion:
Various types of ECG changes occur in moderate to sever hypokalemia and do not specify level of hypokalemia. However AV – block was present in majority cases of severe hypokalemia and presence of AV – block with other features of hypokalemic ECG changes preclude immediate potassium supplementation before the availability of serum potassium level reports.