ECG changes during lithium therapy. A prospective study.

The influence of long-term lithium treatment on the ECG was investigated in 53 consecutive patients. An ECG was recorded prior to and 4 and 12 months after institution of lithium therapy. The most frequently observed change during treatment was flattening or inversion of the T wave. Heart rate decreased and P-Q interval increased slightly during therapy. There was no change in the S-T segment or the Q-T interval corrected for heart rate. Our data indicate that well monitored lithium treatment of patients with serum lithium concentrations of about 0.6 mmol/l does not cause serious ECG abnormalities. In the absence of symptoms or signs of heart disease, routine monitoring of ECG is not necessary during lithium treatment.