RESUMO
The clinical and electrocardiographic data of 35 cases with CAVB were analyzed. They could be divided into two groups: chronic (28 cases) and transcient(7 cases). The primary diseases of the patients in the chronic group were coronary heart disease(CHD) in 11 cases, a condition of unknown cause in 12, and miscellaneous diseases in 5.The clinical and ECG manifestations of the 12 cases with unknown cause were suggestive that the disorder was most likely to be primary degeneration of conduction bundles(PDCB). PDCB differed from CHD by the following:(1) In PDCB, there was neither history of chest pain nor factors vulnerable to CHD being found. No ischemic changes cound be found on the ECG of PDCB cases.(2) The duration of CAVB was longer in PDCB cases (mostly over 3 years) than in CHD cases (all under 2 years).(3) The onset of CAVB occurred at a younger age in PDCB(an average of 50.6 years) than in CHD(an average of 66.3 years).The difference between the two was significant(P