The development of advanced atrioventricular block (AVB) in patients on bradycardic and/or antiarrhythmic therapy (drug-related AVB) represents a clinical challenge, raising the question of whether the AVB is directly caused by these agents (drug-induced AVB) or if the offending drugs exacerbate an underlying conduction system disease. Traditionally, β-blockers, non-dihydropyridine calcium channel blockers, class Ic/III antiarrhythmics, and digoxin have been considered reversible causes of advanced AVB. However, recent evidence shows a weak cause-and-effect relationship between these drugs and AVB in the elderly, along with high recurrence rates of AVB despite initial resolution after drug discontinuation. This may also apply to patients on high doses of these medications, drug combinations, or with additional reversible factors such as hyperkalemia. Despite these considerations, the European Guidelines do not suggest permanent pacing for AVB due to transient causes that are correctable, including bradycardic/antiarrhythmic drug therapy. On the other hand, the American Guidelines recommend permanent pacing for selected patients with symptomatic second- or third-degree AVB on stable, necessary antiarrhythmic or β-blocker treatment, without waiting for drug washout or reversibility. Notably, an accumulating body of evidence indicates that true drug-induced AVB is rare, while recurrence rates are high. Therefore, early permanent pacing should be recommended, especially for frail elderly patients. Moreover, in patients with drug-related AVB and atrial tachyarrhythmias, adopting an early permanent pacing approach seems prudent when bradycardic and/or antiarrhythmic treatment is necessary. Finally, delays in permanent pacing are not justified when temporary pacing is needed, given the increased associated risks in such cases.

Introduction: Electrophysiology (EP) procedures are nowadays the gold-standard method for tachyarrhythmia treatment with impressive success rates, but also with a considerable risk of complications, mainly vascular. A systematic review and meta-analysis was performed to evaluate the safety of ultrasound (US)-guided femoral vein access in EP procedures compared to the traditional anatomic landmark-guided method. Methods: We searched Pubmed (MEDLINE), Embase, Web of Science, and Cochrane electronic databases for relevant entries, dated from January 1st, 2000 to June 30th, 2021. Only observational studies and randomized controlled trials were included in this analysis. Data extraction included study details, patient characteristics, procedure details, and all types of vascular complications. Complications were classified as major if any intervention, prolongation of hospitalization, or readmission was required. Results: 9 studies (1 randomized controlled trial and 8 observational), with 7,858 participants (3,743 in the US-guided group, 4,115 in the control group), were included in the meta-analysis. Overall vascular complication rates were significantly decreased in the US-guided group compared to the control group (1.2 versus 3.2%, RR = 0.38, 95% CI, 0.27 - 0.53), in all EP procedures. Sub-group analysis of AF ablation procedures yielded similar results (RR 0.41, 95% CI, 0.29 - 0.58, p < 0.00001). The event reduction effect was significant for both major and minor vascular complications. Conclusion: US-guided vascular access in EP procedures is associated with significantly reduced vascular complications, compared to the standard anatomic landmark-guided approach, regardless of procedure complexity.