Third degree of atrioventricular block: a rare geriatric complication that may cause sudden death. Remarks on two clinical cases.

Two clinical cases are reported that have in common the electrocardiographic detection of a third degree atrioventricular block (AVB), which occurred in the first case in a man of 78 years, hospitalized in our unit after an accidental fall with an ensuing head trauma, and in the second case, in a woman of 67 years, after cataract surgery on her left eye. The complete or third degree AVB is a bradyarrhythmia characterized by the absence of paroxystic or permanent atrioventricular conduction. Several studies conducted on subjects between the ages of 60 and 85 pointed out that the incidence of AVB-type bradyarrhythmias of a degree greater than the first is extremely rare, i.e., it is close to zero. It is, however, necessary to make an early diagnosis of the AVB, as in many cases it may complicate the patient's clinical progress and may often lead to sudden death. Clinical and experimental observations have shown that electrocardiographic alterations and arrhythmias are frequent complications of cerebral accidents such as head traumas, or of ophthalmic surgery. It is therefore necessary, especially in elderly patients in whom bradyarrhythmias are characterized by the presence of widespread histological alterations of the conduction system, to perform a 24-h monitoring of all adverse events that may lead to an AVB.