The classical indications for ECG include diagnosis of arrhythmia, diagnosis of conduction disorders of the heart impulse and differentiation of various forms of ischaemic heart disease. ECG represents a valuable method of diagnosis even in some other heart diseases. Typical changes of ECG curve, however, accompany even diseases of non-cardiac origin. These findings are of even higher value, as they accompany a series of conditions, which, in the long run, result in serious health damage or imminent life risk. The authors present a collection of ECG findings in selected acute primarily non-cardiac conditions, which may be encountered in the general practitioner consulting room and the early diagnosis may significantly influence prognosis of the patient. The authors outline and comment on basic ECG signs in selected diseases.

        Key words: ECG diagnostics - Acute non-cardiac diseases