16-48: Does drug discontinuation in patients treated with temporary pacemaker reduce permanent pacemaker implantation?

Purpose: The presence of symptomatic third-degree or advanced second-degree atrioventricular (AV) block is a class I indication for permanent pacemaker (PPM) implantation. In patients with concomitant use of AV-blocking drugs, the need for PPM is generally based on the response to drug discontinuation. The objective of our study is to identify predictors for PPM implantation after AV-blocking drugs discontinuation in patients with temporary pacemaker (TPM). Methods: 187 consecutive patients who received a TPM between October 2011 and April 2014 were included retrospectively in our study. AV blocking drugs included digoxin and antiarrhythmic agents classes II-IV. In order to evaluate the impact of these drugs on AV block in each patient, the authors developed a score which included both the number of drugs used and its dose (the latter expressed as a percentage of its maximum recommended dose in clinical practice); the higher the score, the higher the impact of the drugs on AV block in each patient. Results: We included 50 patients with TPM in whom AV-blocking drugs were discontinued (median age of 81.5 [interquartile range 11.3] years, 50.0% males). Among patients discharged without PPM (n = 15, 30.0%), 2 required PPM on follow-up (632 [703] days). Patients who needed PPM on follow-up had lower score (27.8 [55.6] vs 167 [100], p = 0.042) and were under fewer AV-blocking drugs (1.0 [0] vs 2.0 [1.0], p = 0,001). Age (p = 0.566), QRS length (p = 0.866), previous syncope (p = 0.200) and the type of AV-blocking drug (amiodarone [p = 1.000], digoxin [p = 0.371], beta-blockers [p = 1.000] and calcium channel antagonists [p = 1.000]) were not associated with the need for PPM on follow-up. Conclusions: The majority of the patients with TPM had a persistent need for pacing despite AV blocking drugs cessation, which suggests that these drugs may expose a preexistent fragility of the conduction system. However, the lower the dose and number of these drugs, the higher the likelihood of the AV block being secondary to underlying weaknesses. Our score might help in decision making for PPM implantation in patients admitted for drug-induced AV block.