[Long-term course of conduction disorders in 97 patients with an HV interval superior or equal to 70 milliseconds]

The natural history of disorders of conduction is imperfectly known. The presence of an HV interval of 70 milliseconds or more, which is regarded as pathological, usually results in pacemaker implantation. In this study the course of symptoms and disorders of conduction was investigated in 97 patients with an HV interval of 70 ms or more, and therefore equipped with a pacemaker, followed up for a mean period of 26.5 +/- 19.5 months. Among these 97 patients, 65 had presented with one or several syncopes, 14 had experienced feelings of faintness and 18 were asymptomatic. Among patients with symptoms, these totally disappeared in 63 and became milder in the remaining 12 patients. Complete and permanent AV block was observed in 11 patients. The actuarial incidence of complete permanent AV block was about 5 p. 100 per annum until 4 years. The only predictive parameter for such a course was the occurrence of a second degree type 2 or a third degree paroxysmal block prior to pacemaker implantation (significantly associated with the absence of symptoms).