If the leader falters what is the locus of the focus?
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis*; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D009420:Nervous System / Q000503:physiopathology