Heart block: histological and clinical features.

The clinical types of A-V-block and the localization of the underlying lesion to the conduction pathway have been examined in 25 patients. On the evidence of the post mortem studies the lesions were of the following types: 1) Necrosis or fibrosis of ischaemic origin: 13 cases; 2) lesions of inflammatory character: 5 cases; 3) nonspecific lesions; 6 cases; 4) malignant infiltration: one case. Correlations between the site of lesion and the clinical type and pattern of block could be demonstrated in a large proportion of the cases. The characteristic features of the individual types of block and their localization are discussed and a review of the literature is given.