Results of the pilot part of the cardiac drug overdoses hospital registry (storm): focus on drug-induced bradycardia

Aim. Analysis of the relevance of drug-induced bradycardia (DIB) as a medical and social problem, its main regularities and determination of the need for further study of this issue.

Materials and Methods. The register study was performed on 01 Jan 2017-30 Jun 2018  (18 months) at the clinical base of the Ryazan Regional Clinical Cardiology Dispensary. Inclusion criteria were: 1) bradycardia/bradyarrhythmia syndrome with intake of at least one drug with a bradycardic effect (BCE), 2) signing Informed consent to the processing of personal and clinical data. No additional interventions were performed in the diagnosis or treatment of patients within the registry.

Results. During 18 months, 191 patients (age 77.0 [69.0;82.0] years, 26.7% of men) were hospitalized with a verified diagnosis of DIB, which accounted for 52.6% of all cases of hospitalization for drug overdose. During the analyzed period, there was an increase in both the total number of drug overdoses (1.7 times, p<0.001) and overdoses of drugs with BCE (1.8 times, p<0.001). Main clinical manifestations of DIB: reduced heart rate (<50 beats/min – 80.0%, <40 beats/min – 51.1%), sinoatrial (30.4%) and atrioventricular blocks (1^st degree – 8.2%, 2^nd degree – 10.4%, 3^rd degree – 14.1%), syncope (32.6%) and cardiac pauses >3 s (7.4%). Almost all (94.8%) the patients were hospitalized by ambulance, 40.7% – to the intensive care unit; 17.8% required pacemaker implantation; hospital mortality was 5.2%. More than half (54.5%) of hospitalized patients took ≥2 drugs with BCE, 15.7% – ≥3 and 3.14% – ≥4 (both in monotherapy and as a part of a combination): beta-blockers – 68.4%, antiarrhythmic preparations – 38.9%, digoxin – 25.8%, non-dihydropyridine calcium antagonists – 10.5%, I1-imidazoline receptor agonist – 9.5%, and other drugs with BCE – 7.4%. To analyze the cause of DIB, we used clinical data of 135 patients (age 77.0 [69.0;82.0] years, 20.7% of men), who could indicate the exact dose of a taken drug with BCE. Among them, the absolute exceedance of the recommended dose of drugs with BCE was found in 14.1% of cases, while in 85.9% of cases summation/potentiation effect of several drugs with ВСЕ was observed, with intake of each in a therapeutic dose.

Conclusion. The study confirmed high medical and social significance of the problem of DIB, which requires attention of practitioners, pharmacologists and clinical pharmacologists, health care providers, and also continuation of its study.