Assessment of Prescribing and Monitoring Habits for Patients Taking an Antiarrhythmic and Concomitant QTc-Prolonging Antibiotic

Empirical Antimicrobial Therapy and QTc Interval Prolongation in Emergency Medicine

BACKGROUND

QTc prolongation is common though dangerous clinical condition associated with increased risk of life-threatening arrhythmia torsades de pointes. The goal of this short communication is to evaluate the principal causes of risk of QTc prolongation that are observed in an emergency department and discuss the differences between drug- and non-drug-associated factors.

METHODS

The retrospective analysis is carried out on 130 patients that presented a QTc prolongation (>480 ms for males and >470 for female, respectively) admitted to the emergency department of a single Italian hospital. Patients with pacemaker (22) were excluded from this study. For each patient a minimum of 3 ECGs (12 leads) was recorded. Attention is paid to electrolytes disturbances and pharmacotherapy, with a particular emphasis on the use of antibiotics.

RESULTS

Mean age of the patients was 79.6 years (SD=11.3), and females and males were almost equally present (46.6 % F, 53.7 % M). The average QTc value is 492.2 ms (493.3 ms F, 492.8 M). The patients were divided into those with electrolytes disturbances (24.0 %), antimicrobial therapy (35.2%), both antimicrobial therapy and electrolytes disturbances (24.1 %), and other causes of QTc prolongation (16.7 %).

CONCLUSION

This analysis shows the relevance of the empirical therapy established at the admission, in particular for infective diseases, as an important risk factor for the prolongation of QTc. Other factors that can increase the risk are electrolytes alterations, advanced age, cardiovascular diseases, and drug-drug interaction.