Drug-induced bradycardia as a medical and social problem: data from the Cardiac Drug Overdoses Hospital Registry (STORM)

Aim.To analyze hospitalizations due to drug-induced bradyarrhythmia (DIB) over a 5-year period (2014-2018), its clinical characteristics, causes and outcomes. Material and methods. The analysis included all hospitalizations due to DIB at the Ryazan Regional Vascular Center in 2017 and 2018 and retrospectively in 2014. Results.A total of 325 cases of DIB were included in the analysis (age 76,0 [68.0; 82.0] years; men — 26,1%). The proportion of DIB as a hospitalization cause in 2017 increased by 4,3 times compared to 2014 (p<0,001), in 2018 compared to 2014 — by 6,3 times (p<0,001) and compared to 2017 — by 46,2% (p=0,001). We recorded the following manifestations of DIB: bradycardia (<40 bpm — 51,4%), atrioventricular (31,7%) and sinoatrial (29,2%) block, syncope (36,0%), Frederick’s syndrome (8,6%), pauses >3 s (5,9%). Management in intensive care was required in 42,2% of patients, temporary cardiac pacing — in 7,7%, permanent pacemaker — in 6,2%. Mortality rate was 6,2%. Before hospitalization, patients took beta-blockers (65,1%), antiarrhythmic agents (39,6%), cardiac glycosides (23,0%), ^-imidazoline receptor agonist moxonidine (13,5%, its prescription rate increased 8,9 times over 5 years, p=0,004), nondihydropyridine calcium channel blockers (7,9%), and other drugs (15,4%). In 60,1% of patients, ≥2 drugs with bradycardic action were used, in 22,0% — ≥3, in 8,1% — ≥4, in 10,6% — with an excessive single/daily dose. Conclusion.The medical and social significance of DIB have been demonstrated. DIB due to exceeding the recommended dose was associated with independent try of patients to manage the deterioration. In other cases, DIB was due to the summation/ potentiation of several drugs’ action, the comorbidities contributing to the development of bradyarrhythmia and/or changes in pharmacokinetic properties of drugs.