A-V block and A-V dissociation in electrocardiographic surveys of middle school students.
(1) ECG surveys were performed on 12,523 middle school students. The incidence of A-V block was 0.04% (0.37% in males and 0.43% in females). The incidence of A-V dissociation was 0.11% (0.09% in males and0.13% in females). (2) There was no case of Mobitz type II or complete A-V block in this survey. (3) Sixty-four school students were picked at random from the students with A-V block who had been diagnosed by ECG surveys during the last there years and were given the Master's two-step test. The following four types of response were recognized; Type 1, Type 2, Type 3A, B, C, and Type 4. (4) Elevation of ASLO and antistreptkinase (ASK) were found in 6.4% and 13.5%, respectively. The serum cold agglutinin titer was elevated in four of the 12 students tested. (5) Most students with A-V block or A-V dissociation had no past history of severe disease or no major complaints.