Prognosis and Natural History of Drug-Related Bradycardia

Abstract

Background and ObjectivesThe prognosis and natural history of bradycardia related to drugs such as beta-blockers and non-dihydropyridine calcium channel blockers are not well known.Subjects and MethodsWe 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.ResultsThe 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.ConclusionBeta-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.

Trends of Temporary Pacemaker Implant and Underlying Disease Substrate

“…Among the drug‐related bradycardias (DRBs), the BBs were the most common drugs (34%), and SAND was the major bradyarrhythmia (60%), especially in the patients receiving BBs and non‐DHP CCBs, which was consistent with recent studies on the incidence of DRBs (77–82% in SAND vs 18–23% in AVCD) 14,15 …”

Drug-related Atrioventricular Block: Is It a Benign Condition?

“…In our study, we couldn't find any relationship between QRS duration or ventricular rate (as signs of supranodal or infra -nodal disease) [7][8][9] and AV block in drug users; in other word, ECG finding of supra or infra nodal block is not a predictor of permanent pacemaker requirement in patients who consumes drug and are on AV block. Another study that assessed the prognosis of bradycardia related to drugs, evaluated 38 patients with symptomatic bradycardia during beta blocker or calcium channel blocker consumption, and showed that in 10 of 38 cases, bradycardia were not caused by drugs, but were revealed by drugs [10]. Interestingly, in this study, if we omit cases with AV block from that 31 patients who came with symptomatic sinus bradycardia, 27(87%) patients with bradycardia will be resolved by discontinuation of drugs [10].…”

“…Another study that assessed the prognosis of bradycardia related to drugs, evaluated 38 patients with symptomatic bradycardia during beta blocker or calcium channel blocker consumption, and showed that in 10 of 38 cases, bradycardia were not caused by drugs, but were revealed by drugs [10]. Interestingly, in this study, if we omit cases with AV block from that 31 patients who came with symptomatic sinus bradycardia, 27(87%) patients with bradycardia will be resolved by discontinuation of drugs [10]. Comparing these studies, one can argue when a patient referred due to symptomatic bradycardia on beta blocker or calcium channel blockers, if the bradycardia is caused by the second or third degree AV block, it is less probably that the drug induces and if it is caused by sinus bradycardia it is most probably that the drug induces and will regress by discontinuation of drug.…”

Beta-Blocker Use and Risk of Symptomatic Bradyarrhythmias: A Hospital-Based Case-Control Study

“…Similar ECG diagnosis was reported in the above mentioned DRB study that sinus bradycardia and sinus bradycardia with junctional escape beats were most frequently observed. [35] Notably, our study did not report any in-hospital death as a result of symptomatic bradyarrhythmias. The contributing factors towards the irreversibility of bradyarrhythmias were beyond the scope of our study.…”

“…Only 15% of patients who had second or third degree AV block during therapy with β-blockers, verapamil, or diltiazem was "truly caused by drugs". [34] A study by Lee, et al [35] found that β-blockers were the most common drugs associated with drug-related bradycardia (DRB). In this study, drug discontinuation was followed by resolution of bradycardia in 60% of patients.…”