Prognosis and Natural History of Drug-Related Atrioventricular Block

Drug related AV (atrioventricular) block is an important but poorly defined common clinical problem. Little is known about the natural history and prognosis of patients with drug-related AV block. This study was undertaken to assess the prognosis and natural history of drug related AV block (DRB). Out of 44 consecutive patients with drug related second or third degree AV block, 61 % of patients had resolution AV block within 48 hours of withdrawal of the drug. However, 40 % of them developed a recurrence of AV block despite discontinuation of the culprit drug. Electrocardiographic finding of AV nodal or infranodal block was not a predictor of permanent pacemaker requirement in patients with drug related AV block. Beta-blockers were the most common drugs associated with DRB. Conclusion: Sixty-four percent of patients with DRB had persistent or recurrent indication for permanent pacemaker implantation (PM) in 12 months of follow-up, despite the withdrawal of the culprit drug. DRB is not a benign condition and it needs close follow-up. Drug related AV block is often revealed by, rather than actually caused by the drugs.