Beta-Blocker-Related Atrioventricular Conduction Disorders-A Single Tertiary Referral Center Experience.

Background and Objectives: Drug-related bradyarrhythmia is a well-documented major adverse event among beta-blocker users and a potential cause for hospitalization or additional interventions. Whether beta-blocker use is associated with specific bradyarrhythmia presentations, and how this relates to other predisposing factors, is not well known. We aim to evaluate the association between beta-blocker use and the type of atrioventricular (AV) conduction disorder in patients with symptomatic bradycardia. Materials and Methods: We conducted a retrospective cohort study on 596 patients with a primary diagnosis of symptomatic bradyarrhythmia admitted to a single tertiary referral center. Of the cases analyzed, 253 patients were on beta-blocker treatment at presentation and 343 had no bradycardic treatment. We analyzed demographics, clinical and paraclinical parameters in relation to the identified AV conduction disorder. A multivariate regression analysis was performed to explore factors associated with beta-blocker use. Results: Of the 596 patients (mean age 73.9 ± 8.8 years, 49.2% male), 261 (43.8%) had a third-degree AV block, 92 (15.4%) had a second-degree AV block, 128 (21.5%) had slow atrial fibrillation, 93 (15.6%) had sick sinus syndrome and 21 (3.5%) had sinus bradycardia/sinus pauses. Beta-blocker use was associated with the female gender (p < 0.001), emergency admission (p < 0.001), dilated cardiomyopathy (p = 0.003), the lower left ventricular ejection fraction (p = 0.02), mitral stenosis (p = 0.009), chronic kidney disease (p = 0.02), higher potassium levels (p = 0.04) and QRS duration > 120 ms (p = 0.02). Slow atrial fibrillation (OR = 4.2, p < 0.001), sick sinus syndrome (OR = 2.8, p = 0.001) and sinus bradycardia/pauses (OR = 32.9, p < 0.001) were more likely to be associated with beta-blocker use compared to the most common presentation (third-degree AV block), after adjusting for other patient characteristics. Conclusions: Beta-blocker use is more likely to be associated with slow atrial fibrillation, sick sinus syndrome and sinus bradycardia/pauses, compared to a second- or third-degree AV block, after adjusting for other patient factors such as gender, admission type, ECG, comorbidities, cardiac function and lab testing.

Coronary artery bypass graft surgery versus percutaneous coronary intervention in unprotected left main coronary artery disease: A systematic review.

Critical lesion of the unprotected left main coronary disease carries a tremendous mortality burden, often associated with a diabetes status or multivessel disease, with coronary artery bypass grafting being the standard treatment for over 40 years. Percutaneous coronary intervention with drug eluting stents should be taken into consideration and could be a better option for patients with low SYNTAX score as validated by the recently published studies. This review summarizes the major randomized clinical trials and meta-analyses concerning the debate regarding percutaneous coronary intervention with drug eluting stents versus coronary artery bypass grafting for unprotected left main coronary disease, along with the latest European and American revascularization guidelines and tries to shed light on this matter. The most results advocate that there is no convincing difference in survival rate for both therapies, especially in patients with isolated left main disease but with fewer major ischemic events for coronary artery bypass grafting when compared with percutaneous coronary intervention in multivessel coronary artery disease, at the rate of a higher stroke incidence. The gaps in evidence are also highlighted, especially the lack of randomized clinical trials with new generation drug eluting stents versus coronary artery bypass grafting or those regarding the best revascularization strategy for an acute coronary syndrome when unprotected left main coronary disease is involved.