Prognosis and Natural History of Drug-Related Bradycardia

다국어 초록 (Multilingual Abstract)

Background and Objectives: The prognosis and natural history of bradycardia related to drugs such as betablockers
and non-dihydropyridine calcium channel blockers are not well known. Subjects and Methods: We
retrospectively analyzed 38 consecutive patients (age 69±11, 21 women) with drug-related bradycardia (DRB)
between March 2005 and September 2007. A drug-associated etiology for the bradycardia was established based
on the medical history and patient response to drug discontinuation. The mean follow-up duration was 18±8
months. Results: The initial electrocardiogram (ECG) showed sinus bradycardia (heart rate ≤40/min) in 13
patients, sinus bradycardia with junctional escape beats in 18 patients, and third-degree atrioventricular (AV) block
in seven patients. Drug discontinuation was followed by resolution of bradycardia in 60% of patients (n=23).
Among them, five (17.8%) patients resumed taking the culprit medication after discharge and none developed
bradycardia again. Bradycardia persisted in 10 (26.3%) patients despite drug withdrawal, and a permanent pacemaker
was implanted in seven of them. Third-degree AV block, QRS width, and bradycardia requiring temporary
transvenous pacing were significantly associated with the bradycardia caused by drugs. Conclusion: Beta-blockers
were the most common drugs associated with DRB. However, in one quarter of the cases the DRB was not associated
with drugs; in these patients permanent pacemaker implantation should be considered.

다국어 초록 (Multilingual Abstract)

Background and Objectives: The prognosis and natural history of bradycardia related to drugs such as betablockers
and non-dihydropyridine calcium channel blockers are not well known. Subjects and Methods: We
retrospectively analyzed 38 consecutive patients (age 69±11, 21 women) with drug-related bradycardia (DRB)
between March 2005 and September 2007. A drug-associated etiology for the bradycardia was established based
on the medical history and patient response to drug discontinuation. The mean follow-up duration was 18±8
months. Results: The initial electrocardiogram (ECG) showed sinus bradycardia (heart rate ≤40/min) in 13
patients, sinus bradycardia with junctional escape beats in 18 patients, and third-degree atrioventricular (AV) block
in seven patients. Drug discontinuation was followed by resolution of bradycardia in 60% of patients (n=23).
Among them, five (17.8%) patients resumed taking the culprit medication after discharge and none developed
bradycardia again. Bradycardia persisted in 10 (26.3%) patients despite drug withdrawal, and a permanent pacemaker
was implanted in seven of them. Third-degree AV block, QRS width, and bradycardia requiring temporary
transvenous pacing were significantly associated with the bradycardia caused by drugs. Conclusion: Beta-blockers
were the most common drugs associated with DRB. However, in one quarter of the cases the DRB was not associated
with drugs; in these patients permanent pacemaker implantation should be considered.

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