Atrial reciprocal rhythm.
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012849:Sinoatrial Node / Q000503:physiopathology