The work discusses the results obtained in studying intermittent disorders of electrical activation of the atria by recording intracavitary "local" electrograms and additionally augmented ECG from the body surface of 42 patients with noncoronarogenic heart lesions. In 18 patients the intermittent changes in the atrial complex were due to impaired function of the sinus node and disturbance of sinoatrial conduction. In 12 patients functional block of the atrial conduction pathways was revealed, in 8 of them the rhythm was not changed, whereas in 4 the block was attended by Wenckebach's phenomenon. For correct diagnosis it is advisable to record "local" atrial electrograms or P wave of an additionally augmented ECG from the body surface.