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Effects of Encainide on the Function of Implanted Pacemakers
Author(s) -
SALEL ANTONE F.,
SEAGREN SHIRLEY C.,
POOL PETER E.
Publication year - 1989
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1989.tb06147.x
Subject(s) - medicine , discontinuation , placebo , dosing , ambulatory , cardiology , anesthesia , ambulatory ecg , qrs complex , alternative medicine , pathology
The effect of encainide on chronic pacing thresholds was evaluated in 10 pafients, age 64–89, who were exposed to weekly increased encainide dosing (25 mg TID, 50 mg TID, 75 mg TID). Median pacing threshold (mujoules) increased modestly at each period compared to placebo and returned rapidly to baseline after discontinuation.No patient experienced a pacing‐related ciinicai event. One patient had a large threshold increase (566%), but no failure to capture on 24‐hour ECG, and one patient whose threshold increased minimally had clinically insignificant capture failure, the longest event being 3 beats. No other failure to capture was noted. Thus, encainide, like a number of other antiarrhythmic drugs, appears to affect pacing thresholds. At the highest dose of 225 mg/day (75 mg TID, which exceeds the generally recommended dose of 50 mg TID), but not at lower doses, some patients may experience loss of capture that does not appear related to the change in threshold energy required. Increases in the duration of the paced QRS induced by encainide did not predict increases in threshold. Therefore, when higher doses of encainide are required in patients with pacemakers, clinical observation and ambulatory electrocardiographic monitoring should be carried out.