Reciprocal beats initiated by artificial pacemaker.
In conclusion, the underlying mechanism for this rhythm disturbance in our patient is the re-entry phenomenon,  which is dependent upon a localized unidirectional block in the A-V junction. The predisposing factors, including digoxin and Inderal which tend to prolong A-V conduction, are considered for the mechanism of the production of the reciprocal beats in our case. Upon temporary withdrawal of digoxin and Inderal, the re-entry phenomenon has disappeared.
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000503:physiopathology; D006801:Humans; D010138:Pacemaker, Artificial / Q000009:adverse effects*