T wave inversion and ST segment depression in normally conducted beats in patients treated with ventricular demand pacing.
Changes of T waves and ST segments in normally conducted beats are frequently seen in patients treated with ventricular demand pacing. The alteration in the sequence of ventricular activation is accompanied by inversion of T waves and sometimes a depression of ST segments in several leads. These changes have a close resemblance to those often seen in ischaemic heart disease. Some of the clinical implications are illustrated in four case stories. The slow regression of changes after cessation of pacing is particularly emphasised. The time required for complete disappearance of changes was directly related to the duration of ventricular pacing. In contrast to this finding a quickly developed, though temporary, regression was observed during exercise. The development of repolarisation changes requires a certain duration and extent of pacing. Therefore changes are not present in all ventricular paced patients. Consequently, recording of the spontaneous rhythm is proposed as a routine in the pacemaker clinic. The recordings might prove valuable for future comparison in case of suspected myocardial disease.
D000368:Aged; D001919:Bradycardia / Q000628:therapy; D002304:Cardiac Pacing, Artificial; D003327:Coronary Disease / Q000175:diagnosis; D003951:Diagnostic Errors; D004562:Electrocardiography; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis