Not just alternating ectopics.
Alexander A
AA
Sirker
Francis D
FD
Murgatroyd
D000368:Aged; D004417:Dyspnea / Q000209:etiology; D004562:Electrocardiography; D006801:Humans; D008297:Male; D017180:Tachycardia, Ventricular / Q000175:diagnosis*