Prognosis and natural history of drug-related bradycardia.
OBJECTIVE
The prognosis and natural history of bradycardia related to drugs such as beta-blockers and non-dihydropyridine calcium channel blockers are not well known.


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.


CONCLUSIONS
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.
Lee
Jang Hoon
JH
Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea.
Ryu
Hyeon Min
HM
Bae
Myung Hwan
MH
Kwon
Yong Seop
YS
Lee
Ju Hwan
JH
Park
Yongwhi
Y
Heo
Jung-Ho
JH
Lee
Young Soo
YS
Yang
Dong Heon
DH
Park
Hun Sik
HS
Cho
Yongkeun
Y
Chae
Shung Chull
SC
Kim
Yoon-Nyun
YN
Jun
Jae-Eun
JE
Park
Wee-Hyun
WH